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Sample records for acceptable tensile properties

  1. Tensile properties of textile composites

    NASA Technical Reports Server (NTRS)

    Avva, V. Sarma; Sadler, Robert L.; Lyon, Malcolm

    1992-01-01

    The importance of textile composite materials in aerospace structural applications has been gaining momentum in recent years. With a view to better understand the suitability of these materials in aerospace applications, an experimental program was undertaken to assess the mechanical properties of these materials. Specifically, the braided textile preforms were infiltrated with suitable polymeric matrices leading to the fabrication of composite test coupons. Evaluation of the tensile properties and the analyses of the results in the form of strength moduli, Poisson's ratio, etc., for the braided composites are presented. Based on our past experience with the textile coupons, the fabrication techniques have been modified (by incorporating glass microballoons in the matrix and/or by stabilizing the braid angle along the length of the specimen with axial fibers) to achieve enhanced mechanical properties of the textile composites. This paper outlines the preliminary experimental results obtained from testing these composites.

  2. Tensile Properties of GRCop-84

    NASA Technical Reports Server (NTRS)

    Ellis, David L.; Loewenthal, William S.; Yun, Hee-Man

    2012-01-01

    This is a chapter in the final report on GRCop-84 for the Reusable Launch Vehicle (RLV) Second Generation/Project Constellation Program. It contains information on the tensile properties of GRCop-84. GRCop-84 (Cu-8 at.% Cr-4 at.% Nb) was produced by extrusion and Hot Isostatic Pressing (HIPing). Some of the extrusions were rolled to plate and sheet while other extrusions were drawn into tubing. The material was further subjected to various heat treatments corresponding to annealing, anticipated typical brazing conditions, an end-of-life condition and various elevated temperature exposures to attempt to improve creep resistance. As anticipated, cold work increased strength while decreasing ductility. Annealing at 600 C (1112 F) and higher temperatures was effective. An exposure for 100 h at 500 C (932 F) resulted in an increase in strength rather than the anticipated decrease. High temperature simulated-braze cycles and thermal exposures lowered the strength of GRCop-84, but the deceases were small compared to precipitation strengthened copper alloys. It was observed that the excess Cr could form large precipitates that lower the reduction in area though it appears a minimum amount is required. Overall, GRCop-84 exhibits good stability of its tensile properties, which makes it an excellent candidate for rocket engine liners and many other high temperature applications.

  3. Tensile properties of impact ices

    NASA Technical Reports Server (NTRS)

    Chu, M. L.; Scavuzzo, R. J.; Kellackey, C. J.

    1992-01-01

    A special test apparatus was developed to measure the tensile strength of impact ices perpendicular to the direction of growth. The apparatus consists of a split tube carefully machined to minimize the effect of the joint on impact ice strength. The tube is supported in the wind tunnel by two carefully aligned bearings. During accretion the tube is turned slowly in the icing cloud to form a uniform coating of ice on the split tube specimen. The two halves of the split tube are secured firmly by a longitudinal bolt to prevent relative motion between the two halves during ice accretion and handling. Tensile test strength results for a variety of icing conditions were obtained. Both glaze and rime ice conditions were investigated. In general, the tensile strength of impact ice was significantly less than refrigerator ice. Based on the limited data taken, the median strength of rime ice was less than glaze ice. However, the mean values were similar.

  4. Tensile properties of nanoclay reinforced epoxy composites

    NASA Astrophysics Data System (ADS)

    Ku, H.; Trada, Mohan

    2013-08-01

    Kinetic epoxy resin was filled with nanoclay to increase tensile properties of the composite for civil and structural. This project manufactured samples with different percentages by weight of nanoclay in the composites in steps of 1 wt %, which were then post-cured in an oven. The samples were then subjected to tensile tests. The results showed that the composite with 3 wt % of nanoclay produced the highest yield and tensile strengths. However, the Young's modulus increased with increasing nanoparticulate loading. It is hoped that the discussion and results in this work would not only contribute towards the further development of nanoclay reinforced epoxy composites with enhanced material properties, but also provide useful information for the studies of fracture toughness, tensile properties and flexural properties of other composites.

  5. Effects of bathing solution on tensile properties of the cornea.

    PubMed

    Hatami-Marbini, Hamed; Rahimi, Abdolrasol

    2014-03-01

    The cornea is a transparent tissue with the major functions of protecting the inner contents of the eye and refracting incoming light. The biomechanical properties of the cornea strongly depend on the microstructure and composition of the stromal layer, a hydrated bio-gel. The uniaxial strip testing is a convenient and well-accepted experimental technique for characterizing corneal material parameters. It is known that the water content of specimens in this method depends on the osmolality of the bathing solution. The present study was designed to investigate the effects of different bathing solutions on uniaxial tensile material properties of the cornea. The tensile behavior of bovine corneal samples was measured in six different bathing solutions, i.e., hypertonic solution (12% NaCl solution), common preserving isotonic solutions (e.g., phosphate buffer saline, ophthalmic balanced salt solution, and 0.9% NaCl solution), hypotonic solution (distilled water), and neutral solution (mineral oil). It was observed that the bathing solution had significant influence on the tensile behavior of the corneal samples. In particular, the specimens tested in bathing solutions causing less swelling had significantly stiffer tensile properties. Furthermore, a simple mathematical model based on Voigt composite material model was developed to represent the measured solution-dependent tensile properties. The present study suggests that extra attention should be paid to corneal thickness (hydration) in uniaxial tensile experiments. It also provides important data on tensile properties of the cornea; such information could significantly contribute to improving the accuracy of numerical predictions of corneal biomechanics. PMID:24333541

  6. Tensile mechanical properties of human forearm tendons.

    PubMed

    Weber, J F; Agur, A M R; Fattah, A Y; Gordon, K D; Oliver, M L

    2015-09-01

    Previous studies of the mechanical properties of tendons in the upper limb have used embalmed specimens or sub-optimal methods of measurement. The aim of this study was to determine the biomechanical properties of all tendons from five fresh frozen cadaveric forearms using updated methodology. The cross-sectional area of tendons was accurately measured using a laser reflectance system. Tensile testing was done in a precision servo-hydraulic device with cryo-clamp fixation. We determined that the cross-sectional area of some tendons is variable and directly influences the calculated material properties; visual estimation of this is unreliable. Data trends illustrate that digital extensor tendons possess the greatest tensile strength and a higher Young's modulus than other tendon types. PMID:25940499

  7. Dynamic tensile properties of human placenta.

    PubMed

    Manoogian, Sarah J; Bisplinghoff, Jill A; McNally, Craig; Kemper, Andrew R; Santago, Anthony C; Duma, Stefan M

    2008-12-01

    Automobile crashes are the largest cause of injury death for pregnant females and the leading cause of traumatic fetal injury mortality in the United States. Computational models, useful tools to evaluate the risk of fetal loss in motor vehicle crashes, are based on a limited number of quasi-static material tests of the placenta. This study presents a total of 20 dynamic uniaxial tensile tests on the maternal side of the placenta and 10 dynamic uniaxial tensile tests on the chorion layer of the placenta. These tests were completed from 6 human placentas to determine material properties at a strain rate of 7.0 strains/s. The results show that the average peak strain at failure for both the maternal portion and the chorion layer of the placenta are similar with a value of 0.56 and 0.61, respectively. However, the average failure stress for the chorion layer, 167.8 kPa, is much higher than the average failure stress for the placenta with the chorionic plate removed, 18.6 kPa. This is due to differences in the structure and function of these layers in the placenta. In summary, dynamic loading data for the placenta have been determined for use in computational modeling of pregnant occupant kinematics in motor vehicle crashes. Moreover the computational model should utilize the material properties for the placenta without the chorion layer. PMID:18996533

  8. Tensile properties of the human glenoid labrum

    PubMed Central

    Smith, C D; Masouros, S D; Hill, A M; Wallace, A L; Amis, A A; Bull, A M J

    2008-01-01

    Human fresh-frozen cadaveric glenoid labrae from 16 donors were harvested and ten of these had no gross degeneration. These ten were divided into eight equal circumferential sections. Each section was cut to produce test-samples from the core layer with a cross-section of 1 × 1 mm. Tensile testing was performed within a controlled environment unit at 37 ± 1 °C and 100% relative humidity. Each test-sample was precycled to a quasi-static state to alleviate the effects of deep-freezing, prior to final testing. The tangent modulus was calculated for each test-sample before and after a 5-min period of stress relaxation and at yield. The mean elastic modulus and yield stress of the glenoid labrum were 22.8 ± 11.4 and 2.5 ± 2.1 MPa, respectively. The anterosuperior portion had a lower elastic modulus and lower yield stress than the inferior portion (both P < 0.02). The pre-stress relaxation tangent modulus was significantly lower than the post-stress relaxation tangent modulus for all portions of the labrum. The glenoid labrum has similar tensile material properties to articular cartilage. Its elastic modulus varies around its circumference. This suggests that the labrum may encounter different forces at different positions. PMID:18031481

  9. Tensile-property characterization of thermally aged cast stainless steels.

    SciTech Connect

    Michaud, W. F.; Toben, P. T.; Soppet, W. K.; Chopra, O. K.; Energy Technology

    1994-03-03

    The effect of thermal aging on tensile properties of cast stainless steels during service in light water reactors has been evaluated. Tensile data for several experimental and commercial heats of cast stainless steels are presented. Thermal aging increases the tensile strength of these steels. The high-C Mo-bearing CF-8M steels are more susceptible to thermal aging than the Mo-free CF-3 or CF-8 steels. A procedure and correlations are presented for predicting the change in tensile flow and yield stresses and engineering stress-vs.-strain curve of cast stainless steel as a function of time and temperature of service. The tensile properties of aged cast stainless steel are estimated from known material information, i.e., chemical composition and the initial tensile strength of the steel. The correlations described in this report may be used for assessing thermal embrittlement of cast stainless steel components.

  10. Tensile-property characterization of thermally aged cast stainless steels

    SciTech Connect

    Michaud, W.F.; Toben, P.T.; Soppet, W.K.; Chopra, O.K.

    1994-02-01

    The effect of thermal aging on tensile properties of cast stainless steels during service in light water reactors has been evaluated. Tensile data for several experimental and commercial heats of cast stainless steels are presented. Thermal aging increases the tensile strength of these steels. The high-C Mo-bearing CF-8M steels are more susceptible to thermal aging than the Mo-free CF-3 or CF-8 steels. A procedure and correlations are presented for predicting the change in tensile flow and yield stresses and engineering stress-vs.-strain curve of cast stainless steel as a function of time and temperature of service. The tensile properties of aged cast stainless steel are estimated from known material information, i.e., chemical composition and the initial tensile strength of the steel. The correlations described in this report may be used for assessing thermal embrittlement of cast stainless steel components.

  11. Tensile properties of the inferior glenohumeral ligament.

    PubMed

    Bigliani, L U; Pollock, R G; Soslowsky, L J; Flatow, E L; Pawluk, R J; Mow, V C

    1992-03-01

    The tensile properties of the inferior glenohumeral ligament have been determined in 16 freshly frozen cadaver shoulders. The inferior glenohumeral ligament was divided into three anatomical regions: a superior band, an anterior axillary pouch, and a posterior axillary pouch. This yielded 48 bone-ligament-bone specimens, which were tested to failure in uniaxial tension. The superior band was consistently the thickest region, averaging 2.79 mm. The thickness of the inferior glenohumeral ligament decreased from antero-superiorly to postero-inferiorly. The resting length of all three anatomical regions was not statistically different. Total specimen strain to failure for all bone-ligament-bone specimens averaged 27%. Variations occurred between the three regions, with the anterior pouch specimens failing at a higher strain (34%) than those from the superior band (24%) or the posterior pouch (23%). Strain to failure for the ligament midsubstance (11%) was found to be significantly less than that for the entire specimen (27%). Thus, larger strain must occur near the insertion sites of the inferior glenohumeral ligament. Stress at failure was found to be nearly identical for the three regions of the ligament, averaging 5.5 MPa. These values are lower than those reported for other soft tissues, such as the anterior cruciate ligament and patellar tendon. The anterior pouch was found to be less stiff than the other two regions, perhaps suggesting that it is composed of more highly crimped collagen fibers. Three failure sites were seen for the inferior glenohumeral ligament: the glenoid insertion (40%), the ligament substance (35%), and the humeral insertion (25%). In addition, significant capsular stretching occurred before failure, regardless of the failure mode. PMID:1740736

  12. Tensile properties of vanadium-base alloys with a tungsten/inert-gas weld zone

    SciTech Connect

    Loomis, B.A.; Konicek, C.F.; Nowicki, L.J.; Smith, D.L.

    1992-12-31

    The tensile properties of V-(0-20)Ti and V-(O-15)Cr-5Ti alloys after butt-joining by tungsten/inert-gas (TIG) welding were determined from tests at 25{degrees}C. Tensile tests were conducted on both annealed and cold-worked materials with a TIG weld zone. The tensile properties of these materials were strongly influenced by the microstructure in the heat-affected zone adjacent to the weld zone and by the intrinsic fracture toughness of the alloys. TIG weld zones in these vanadium-base alloys had tensile properties comparable to those of recrystallized alloys without a weld zone. Least affected by the TIG welding were tensile properties of the V-5Ti and V-5Cr-5Ti alloys. Although the tensile properties of the V-5Ti and V- 5Cr-5Ti alloys with a TIG weld zone were acceptable for structural material, these properties would be improved by optimization of the welding parameters for minimum grain size in the heat-affected zone.

  13. Tensile properties of amorphous diamond films

    SciTech Connect

    Lavan, D.A.; Hohlfelder, R.J.; Sullivan, J.P.; Friedmann, T.A.; Mitchell, M.A.; Ashby, C.I.

    1999-12-02

    The strength and modulus of amorphous diamond, a new material for surface micromachined MEMS and sensors, was tested in uniaxial tension by pulling laterally with a flat tipped diamond in a nanoindenter. Several sample designs were attempted. Of those, only the single layer specimen with a 1 by 2 {micro}m gage cross section and a fixed end rigidly attached to the substrate was successful. Tensile load was calculated by resolving the measured lateral and normal forces into the applied tensile force and frictional losses. Displacement was corrected for machine compliance using the differential stiffness method. Post-mortem examination of the samples was performed to document the failure mode. The load-displacement data from those samples that failed in the gage section was converted to stress-strain curves using carefully measured gage cross section dimensions. Mean fracture strength was found to be 8.5 {+-} 1.4 GPa and the modulus was 831 {+-} 94 GPa. Tensile results are compared to hardness and modulus measurements made using a nanoindenter.

  14. Tensile properties of palladium-silver alloys with absorbed hydrogen

    NASA Technical Reports Server (NTRS)

    Smith, R. J.; Otterson, D. A.

    1975-01-01

    The alloys 90Pd-10Ag, 80Pd-20Ag, 70Pd-30Ag, 60Pd-40Ag, and 50Pd-50Ag containing absorbed hydrogen were tested in tension. The results show the tensile properties to be independent of the phase transition. Also, hydrogen in the lattice does not necessarily cause embrittlement or poor elongation. The changes in the tensile properties appear dependent on the electron to atom site ratio.

  15. Tensile properties of the modified 13Cr martensitic stainless steels

    NASA Astrophysics Data System (ADS)

    Mabruri, Efendi; Anwar, Moch. Syaiful; Prifiharni, Siska; Romijarso, Toni B.; Adjiantoro, Bintang

    2016-04-01

    This paper reports the influence of Mo and Ni on the tensile properties of the modified 13Cr martensitic stainless steels in tempered condition. Four steels with different content of Mo and Ni were prepared by induction melting followed by hot forging, quenching and tempering. The experimental results showed that the addition of about 1% and 3% Mo has a beneficial effect to increase both the tensile strength and the elongation of the steels. On the contrary, the addition of about 3% Ni into the martensitic stainless steel results in decreasing of both the tensile strength and the elongation. Among the alloys investigated the 13Cr3Mo type steel exhibited largest tensile strength of 1348 MPa and largest elongation of 12%. The observation on the tensile fractured surfaces by using scanning electron microscope supported these findings.

  16. Tensile properties of as-cast iron-aluminide alloys

    SciTech Connect

    Viswanathan, S.; McKamey, C.G.; Maziasz, P.J.

    1995-01-01

    Room-temperature tensile properties of as-cast Fe{sub 3}Al-based FA-129 alloy were investigated. Tensile properties were obtained in the as-cast condition in air, oxygen, and water-vapor environments, and after homogenization at 700, 900, and 1200{degrees}C. Transmission electron microscopy (MM) was used to characterize ordered phases and dislocation structure, and optical metallography and scanning electron microscopy (SEM) were used to characterize the grain microstructure and fracture morphology. Tensile properties in the as-cast condition exhibited an environmental effect; tensile ductilities in oxygen atmosphere were greater than those obtained in laboratory air. Homogenized samples of FA-129 alloy exhibited almost twice the ductility found in the as-cast condition. Microstructural characterization of the homogenized samples and comparison of the as-cast and homogenized microstructures provided clues that helped to explain the poor ductility in the as-cast state.

  17. Tensile and fatigue properties of Inconel 718 at cryogenic temperatures

    NASA Technical Reports Server (NTRS)

    Malin, C. O.; Schmidt, E. H.

    1969-01-01

    Tests to determine the tensile and fatigue properties of Inconel 718 at cryogenic temperatures show that the alloy increases in strength at low temperatures, with very little change in toughness. The effect of surface finish and grain size on the fatigue properties was also determined.

  18. Maximizing Tensile Strain in Germanium Nanomembranes for Enhanced Optoelectronic Properties

    NASA Astrophysics Data System (ADS)

    Sanchez Perez, Jose Roberto

    Silicon, germanium, and their alloys, which provide the leading materials platform of microelectronics, are extremely inefficient light emitters because of their indirect fundamental energy band gap. This basic materials property has so far hindered the development of group-IV photonic-active devices, including light emitters and diode lasers, thereby significantly limiting our ability to integrate electronic and photonic functionalities at the chip level. Theoretical studies have predicted that tensile strain in Ge lowers the direct energy band gap relative to the indirect one, and that, with sufficient strain, Ge becomes direct-band gap, thus enabling facile interband light emission and the fabrication of Group IV lasers. It has, however, not been possible to impart sufficient strain to Ge to reach the direct-band gap goal, because bulk Ge fractures at much lower strains. Here it is shown that very thin sheets of Ge(001), called nanomembranes (NMs), can be used to overcome this materials limitation. Germanium nanomembranes (NMs) in the range of thicknesses from 20nm to 100nm were fabricated and then transferred and mounted to a flexible substrate [a polyimide (PI) sheet]. An apparatus was developed to stress the PI/NM combination and provide for in-situ Raman measurements of the strain as a function of applied stress. This arrangement allowed for the introduction of sufficient biaxial tensile strain (>1.7%) to transform Ge to a direct-band gap material, as determined by photoluminescence (PL) measurements and theory. Appropriate shifts in the emission spectrum and increases in PL intensities were observed. The advance in this work was nanomembrane fabrication technology; i.e., making thin enough Ge sheets to accept sufficiently high levels of strain without fracture. It was of interest to determine if the strain at which fracture ultimately does occur can be raised, by evaluating factors that initiate fracture. Attempts to assess the effect of free edges (enchant

  19. Tensile properties of austempered ductile iron under thermomechanical treatment

    SciTech Connect

    Achary, J.

    2000-02-01

    A new processing method was investigated for improving the strength and elongation of austempered ductile iron (ADI) by grain refinement of parent austenite using thermomechanical treatment. The material was deformed at the austenitization temperature by single and multipass rolling before the austempering treatment. The effects of the amount of deformation, austenitization temperature, austempering temperatures, reaustenitization, and secondary deformation on the tensile properties were studied. The properties obtained using the method were compared with those of the ASTM standards. The effect of deformation on the graphite shape was also studied. Tensile strength/yield strength/elongation values were found to increase with increasing austenite deformation up to 40% and then to start decreasing. Tensile strength/yield strength and elongation values of 1,700 MPa/1,300 MPa/5% and 1,350 MPa/920 MPa/15% can be achieved with this method in the ranges of variables studied.

  20. Electronic, mechanical and dielectric properties of silicane under tensile strain

    SciTech Connect

    Jamdagni, Pooja Sharma, Munish; Ahluwalia, P. K.; Kumar, Ashok; Thakur, Anil

    2015-05-15

    The electronic, mechanical and dielectric properties of fully hydrogenated silicene i.e. silicane in stable configuration are studied by means of density functional theory based calculations. The band gap of silicane monolayer can be flexibly reduced to zero when subjected to bi-axial tensile strain, leading to semi-conducting to metallic transition, whereas the static dielectric constant for in-plane polarization increases monotonically with increasing strain. Also the EEL function show the red shift in resonance peak with tensile strain. Our results offer useful insight for the application of silicane monolayer in nano-optical and electronics devices.

  1. Electronic, mechanical and dielectric properties of silicane under tensile strain

    NASA Astrophysics Data System (ADS)

    Jamdagni, Pooja; Kumar, Ashok; Sharma, Munish; Thakur, Anil; Ahluwalia, P. K.

    2015-05-01

    The electronic, mechanical and dielectric properties of fully hydrogenated silicene i.e. silicane in stable configuration are studied by means of density functional theory based calculations. The band gap of silicane monolayer can be flexibly reduced to zero when subjected to bi-axial tensile strain, leading to semi-conducting to metallic transition, whereas the static dielectric constant for in-plane polarization increases monotonically with increasing strain. Also the EEL function show the red shift in resonance peak with tensile strain. Our results offer useful insight for the application of silicane monolayer in nano-optical and electronics devices.

  2. Tensile properties of titanium electrolytically charged with hydrogen

    NASA Technical Reports Server (NTRS)

    Smith, R. J.; Otterson, D. A.

    1971-01-01

    Yield strength, ultimate tensile strength, and elongation were studied for annealed titanium electrolytically charged with hydrogen. The hydrogen was present as a surface hydride layer. These tensile properties were generally lower for uncharged titanium than for titanium with a continuous surface hydride; they were greater for uncharged titanium than for titanium with an assumed discontinuous surface hydride. We suggest that the interface between titanium and titanium hydride is weak. And the hydride does not necessarily impair strength and ductility of annealed titanium. The possibility that oxygen and/or nitrogen can embrittle titanium hydride is discussed.

  3. Surface, structural and tensile properties of proton beam irradiated zirconium

    NASA Astrophysics Data System (ADS)

    Rafique, Mohsin; Chae, San; Kim, Yong-Soo

    2016-02-01

    This paper reports the surface, structural and tensile properties of proton beam irradiated pure zirconium (99.8%). The Zr samples were irradiated by 3.5 MeV protons using MC-50 cyclotron accelerator at different doses ranging from 1 × 1013 to 1 × 1016 protons/cm2. Both un-irradiated and irradiated samples were characterized using Field Emission Scanning Electron Microscope (FESEM), X-ray Diffraction (XRD) and Universal Testing Machine (UTM). The average surface roughness of the specimens was determined by using Nanotech WSxM 5.0 develop 7.0 software. The FESEM results revealed the formation of bubbles, cracks and black spots on the samples' surface at different doses whereas the XRD results indicated the presence of residual stresses in the irradiated specimens. Williamson-Hall analysis of the diffraction peaks was carried out to investigate changes in crystallite size and lattice strain in the irradiated specimens. The tensile properties such as the yield stress, ultimate tensile stress and percentage elongation exhibited a decreasing trend after irradiation in general, however, an inconsistent behavior was observed in their dependence on proton dose. The changes in tensile properties of Zr were associated with the production of radiation-induced defects including bubbles, cracks, precipitates and simultaneous recovery by the thermal energy generated with the increase of irradiation dose.

  4. Tensile Properties of Contractile and Synthetic Vascular Smooth Muscle Cells

    NASA Astrophysics Data System (ADS)

    Miyazaki, Hiroshi; Hasegawa, Yoshitaka; Hayashi, Kozaburo

    Tensile properties of vascular smooth muscle cells (VSMCs) of synthetic and contractile phenotypes were determined using a newly developed tensile test system. Synthetic and contractile VSMCs were isolated from the rabbit thoracic aorta with an explant and an enzymatic digestion method, respectively. Each cell floated in Hanks' balanced salt solution of 37°C was attached to the fine tips of a pair of micropipettes with a cell adhesive and, then, stretched at the rate of 6µm/sec by moving one of the micropipettes with a linear actuator. Load applied to the cell was measured with a cantilever-type load cell; its elongation was determined from the distance between the micropipette tips using a video dimension analyzer. The synthetic and contractile VSMCs were not broken even at the tensile force of 2.4µN and 3.4µN, respectively. Their stiffness was significantly higher in contractile phenotype (0.17N/m) than in synthetic one (0.09N/m). The different tensile properties between synthetic and contractile cells are attributable to the differences in cytoskeletal structures and contractile apparatus.

  5. Tensile Properties of Hydrogels and of Snake Skin

    NASA Technical Reports Server (NTRS)

    Hinkley, Jeffrey A.; Savitzky, Alan H.; Rivera, Gabriel; Gehrke, Stevin H.

    2002-01-01

    Stimulus-responsive or 'smart' gels are of potential interest as sensors and actuators, in industrial separations, and as permeable delivery systems. In most applications, a certain degree of mechanical strength and toughness will be required, yet the large-strain behavior of gels has not been widely reported. Some exceptions include work on gelatin and other food gels, some characterization of soft gels applicable for in-vitro cell growth studies, and toughness determinations on commercial contact lens materials. In general, it can be anticipated that the gel stiffness will increase with increasing degree of crosslinking, but the tensile strength may go through a maximum. Gel properties can be tailored by varying not only the degree of crosslinking, but also the polymer concentration and the nature of the polymer backbone (e.g. its stiffness or solubility). Polypeptides provide an especially interesting case, where secondary structure affects trends in moduli and conformational transitions may accompany phase changes. A few papers on the tensile properties of responsive gels have begun to appear. The responsive hydrogel chosen for the present study, crosslinked hydroxypropylcellulose, shrinks over a rather narrow temperature range near 44 C. Some vertebrate skin is also subject to substantial strain. Among reptiles, the morphologies of the skin and scales show wide variations. Bauer et al. described the mechanical properties and histology of gecko skin; longitudinal tensile properties of snake skin were examined by Jayne with reference to locomotion. The present measurements focus on adaptations related to feeding, including the response of the skin to circumferential tension. Tensile properties will be related to interspecific and regional variation in skin structure and folding.

  6. Hoop Tensile Properties of Ceramic Matrix Composite Cylinders

    NASA Technical Reports Server (NTRS)

    Verrilli, Michael J.; DiCarlo, James A.; Yun, HeeMan; Barnett, Terry

    2004-01-01

    Tensile stress-strain properties in the hoop direction were obtained for 100-mm diameter SiC/SiC ceramic matrix composite cylinders using ring specimens machined form the cylinder ends. The cylinders were fabricated from 2D balanced SiC fabric with several material variants, including wall thickness (6,8, and 12 plies), SiC fiber type (Sylramic, Sylramic-iBN, Hi-Nicalon, and Hi-Nicalon S), fiber sizing type, and matrix type (full CVI SiC, and partial CVI SiC plus slurry cast + melt-infiltrated SiC-Si). Fiber ply splices existed in all the hoops. Tensile hoop measurements are made at room temperature and 1200 C using hydrostatic ring test facilities. The failure mode of the hoops, determined through microstructural examination, is presented. The hoop properties are compared with in-plane data measured on flat panels using same material variants, but containing no splices.

  7. Effect of helium on tensile properties of vanadium alloys

    SciTech Connect

    Chung, H.M.; Billone, M.C.; Smith, D.L.

    1997-08-01

    Tensile properties of V-4Cr-4Ti (Heat BL-47), 3Ti-1Si (BL-45), and V-5Ti (BL-46) alloys after irradiation in a conventional irradiation experiment and in the Dynamic Helium Charging Experiment (DHCE) were reported previously. This paper presents revised tensile properties of these alloys, with a focus on the effects of dynamically generated helium of ductility and work-hardening capability at <500{degrees}C. After conventional irradiation (negligible helium generation) at {approx}427{degrees}C, a 30-kg heat of V-4Cr-4Ti (BL-47) exhibited very low uniform elongation, manifesting a strong susceptibility to loss of work-hardening capability. In contrast, a 15-kg heat of V-3Ti-1Si (BL -45) exhibited relatively high uniform elongation ({approx}4%) during conventional irradiation at {approx}427{degrees}C, showing that the heat is resistant to loss of work-hardening capability.

  8. Tensile properties of modified 9 Cr-1 Mo steel

    SciTech Connect

    Sikka, V.K.; McDonald, R.E.; Booker, M.K.; Bodine, G.C.

    1982-02-01

    Tensile properties of commercial heats of modified 9 Cr-1 Mo alloy are presented for test temperatures in the range from room temperature to 760/sup 0/C. Data included the effects of melting practice, compositional differences, strain rate (8.0 to 0.00008/min), postweld heat treatment (1 through 112 h at 732/sup 0/C), tempering temperature (732 and 746/sup 0/C versus 760/sup 0/C), isothermal annealing (1038/sup 0/C for 1 h and 704/sup 0/C for 24 h followed by AC), and thermal aging (5000 and 11,600 h at 538, 593, and 649/sup 0/C). The average-to-minimum property range for the yield and ultimate tensile strengths was compared with the similar data range for standard 9 Cr-1 Mo alloy. Tensile data on commercial heats were used to set the room-temperature specified minimum values for the alloy. The conservativeness of the specified minimum values was checked against the data at several strain rates, data after postweld heat treatment at 732/sup 0/C up to 112 h, and data on thermally aged material.

  9. Tensile and impact properties of iron-aluminum alloys

    SciTech Connect

    Alexander, D.J.; Sikka, V.K.

    1993-12-31

    Tensile and impact tests have been conducted on specimens from a series of five heats of iron-aluminum alloys. These results have been compared to data for the iron aluminide alloy FA-129. The transition temperatures of all of the Fe{sub 3}Al-based alloys were similar, but the simple ternary alloy had a much higher upper-shelf energy. The reduced aluminum alloys [based on Fe-8Al (wt %)] had lower transition temperatures and higher upper-shelf energy levels than the Fe{sub 3}Al-type alloys. The reduced aluminum alloy with yttrium showed excellent tensile properties, with a room temperature total elongation of 40%, and a very high upper-shelf energy level. Despite the high tensile ductility at room temperature, the transition temperature of the yttrium-containing alloy was still about 150 C, compared to approximately 300 C for FA-129. In general, the microstructures were coarse and anisotropic. The fracture processes were dominated by second-phase particles.

  10. Tensile properties of as-cast iron-aluminide alloys

    SciTech Connect

    Viswanathan, S.; McKamey, C.G.; Maziasz, P.J.; Sikka, V.K.

    1993-07-01

    Room-temperature tensile properties of as-cast Fe{sub 3}Al, Fe{sub 3}Al with chromium, and Fe{sub 3}Al-based FA-129 alloy are investigated. Tensile properties were obtained in the as-cast condition and after homogenization at 700, 900, and 1,200{degrees}C. Transmission electron microscopy (TEM) was used to characterize ordered phases, and optical metallography and scanning electron microscopy (SEM) were used to characterize the microstructure and fracture morphology. The results indicate that the low ductility of as-cast Fe{sub 3}Al-based alloys may be related to the relatively large grain size in the cast condition, the low dislocation density in as-cast samples, and the presence of the DO{sub 3} ordered phase. Homogenized samples of FA-129 alloy exhibited almost twice the ductility of the as-cast the as-cast and homogenized microstructures may provide a clue to the poor ductility in the as-cast state.

  11. Tensile properties of as-cast iron-aluminide alloys

    SciTech Connect

    Viswanathan, S.: McKamey, C.G.; Maziasz, P.J.; Sikka, V.K.

    1993-07-01

    Room-temperature tensile properties of as-cast Fe{sub 3}Al, Fe{sub 3}Al with chromium, and Fe{sub 3}Al-based FA-129 alloy are investigated. Tensile properties were obtained in the as-cast condition and after homogenization at 700, 900, and 1200{degrees}C. Transmission electron microscopy (TEM) was used to characterize ordered phases, and optical metallography and scanning electron microscopy (SEM) were used to characterize the microstructure and fracture morphology. The results indicate that the low ductility of as-cast Fe{sub 3}Al-based alloys may be related to the relatively large grain size in the cast condition, the low dislocation density in as-cast samples, and the presence of the D0{sub 3} ordered phase. Homogenized samples of FA-129 alloy exhibited almost twice the ductility of the as-cast condition. Microstructural characterization of the homogenized samples and comparison of the as-cast and homogenized microstructures may provide a clue to the poor ductility in the as-cast state.

  12. Tensile Mechanical Properties of Swine Cortical Mandibular Bone

    PubMed Central

    Brosh, Tamar; Rozitsky, Doron; Geron, Silvia; Pilo, Raphael

    2014-01-01

    Temporary orthodontic mini implants serve as anchorage devices in orthodontic treatments. Often, they are inserted in the jaw bones, between the roots of the teeth. The stability of the mini implants within the bone is one of the major factors affecting their success and, consequently, that of the orthodontic treatment. Bone mechanical properties are important for implant stability. The aim of this study was to determine the tensile properties of the alveolar and basal mandible bones in a swine model. The diametral compression test was employed to study the properties in two orthogonal directions: mesio-distal and occluso-gingival. Small cylindrical cortical bone specimens (2.6 mm diameter, 1.5 mm thickness) were obtained from 7 mandibles using a trephine drill. The sites included different locations (anterior and posterior) and aspects (buccal and lingual) for a total of 16 specimens from each mandible. The load-displacement curves were continuously monitored while loading half of the specimens in the oclluso-gingival direction and half in the mesio-distal direction. The stiffness was calculated from the linear portion of the curve. The mesio-distal direction was 31% stiffer than the occluso-gingival direction. The basal bone was 40% stiffer than the alveolar bone. The posterior zone was 46% stiffer than the anterior zone. The lingual aspect was stiffer than the buccal aspect. Although bone specimens do not behave as brittle materials, the diametral compression test can be adequately used for determining tensile behavior when only small bone specimens can be obtained. In conclusion, to obtain maximal orthodontic mini implant stability, the force components on the implants should be oriented mostly in the mesio-distal direction. PMID:25463971

  13. Tensile properties of ADI material in water and gaseous environments

    SciTech Connect

    Rajnovic, Dragan; Balos, Sebastian; Sidjanin, Leposava; Eric Cekic, Olivera; Grbovic Novakovic, Jasmina

    2015-03-15

    Austempered ductile iron (ADI) is an advanced type of heat treated ductile iron, having comparable mechanical properties as forged steels. However, it was found that in contact with water the mechanical properties of austempered ductile irons decrease, especially their ductility. Despite considerable scientific attention, the cause of this phenomenon remains unclear. Some authors suggested that hydrogen or small atom chemisorption causes the weakening of the surface atomic bonds. To get additional reliable data of that phenomenon, in this paper, two different types of austempered ductile irons were tensile tested in various environments, such as: argon, helium, hydrogen gas and water. It was found that only the hydrogen gas and water gave a statistically significant decrease in mechanical properties, i.e. cause embrittlement. Furthermore, the fracture surface analysis revealed that the morphology of the embrittled zone near the specimen surface shares similarities to the fatigue micro-containing striation-like lines, which indicates that the morphology of the brittle zone may be caused by cyclic local-chemisorption, micro-embrittlement and local-fracture. - Highlights: • In contact with water and other liquids the ADI suddenly exhibits embrittlement. • The embrittlement is more pronounced in water than in the gaseous hydrogen. • The hydrogen chemisorption into ADI surface causes the formation of a brittle zone. • The ADI austempered at lower temperatures (300 °C) is more resistant to embrittlement.

  14. Mechanical properties of gold twinned nanocubes under different triaxial tensile rates

    NASA Astrophysics Data System (ADS)

    Yang, Zailin; Zhang, Guowei; Luo, Gang; Sun, Xiaoqing; Zhao, Jianwei

    2016-08-01

    The gold twinned nanocubes under different triaxial tensile rates are explored by molecular dynamics simulation. Hydrostatic stress and Mises stress are defined in order to understand triaxial stresses. Twin boundaries prevent dislocations between twin boundaries from developing and dislocation angles are inconspicuous, which causes little difference between triaxial stresses. The mechanical properties of the nanocubes under low and high tensile rates are different. The curves of nanocubes under high tensile rates are more abrupt than those under low tensile rates. When the tensile rate is extremely big, the loadings are out of the nanocubes and there are not deformation and fracture in the internal nanocubes.

  15. Tensile properties of a morphologically split supraspinatus tendon.

    PubMed

    Matsuhashi, Tomoya; Hooke, Alexander W; Zhao, Kristin D; Goto, Akira; Sperling, John W; Steinmann, Scott P; An, Kai-Nan

    2014-07-01

    The supraspinatus tendon consists morphologically of two sub-regions, anterior and posterior. The anterior sub-region is thick and tubular while the posterior is thin and strap-like. The purpose of this study was to compare the structural and mechanical properties of the anterior and posterior sub-regions of the supraspinatus tendon. The supraspinatus tendons from seven human cadaveric shoulders were morphologically divided into the anterior and posterior sub-regions. Length, width, and thickness were measured. A servo-hydraulic testing machine (MTS Systems Corporation, Minneapolis, MN) was used for tensile testing. The maximal load at failure, modulus of elasticity and ultimate tendon stress were calculated. Repeated measures were used for statistical comparisons. The mean anterior tendon cross-sectional area was 47.3 mm(2) and the posterior was 32.1 mm(2) . Failure occurred most often at the insertion site: anterior (5/7) and posterior (6/7). All parameters of the anterior sub-region were significantly greater than those of the posterior sub-region. The moduli of elasticity at the insertion site were 592.4 MPa in the anterior sub-region and 217.7 MPa in the posterior (P = 0.01). The ultimate failure loads were 779.2 N in the anterior sub-region and 335.6 N in the posterior (P = 0.003). The ultimate stresses were 22.1 MPa in the anterior sub-region and 11.6 MPa in the posterior (P = 0.008). We recognized that the anterior and posterior sub-regions of the SSP tendon have significantly different mechanical properties. In a future study, we need to evaluate how best to repair an SSP tendon considering these region-specific properties. PMID:24214830

  16. High temperature tensile properties of V-4Cr-4Ti

    SciTech Connect

    Zinkle, S.J.; Rowcliffe, A.F.; Stevens, C.O.

    1998-09-01

    Tensile tests have been performed on V-4Cr-4Ti at 750 and 800 C in order to extend the data base beyond the current limit of 700 C. From comparison with previous measurements, the yield strength is nearly constant and tensile elongations decrease slightly with increasing temperature between 300 and 800 C. The ultimate strength exhibits an apparent maximum near 600 C (attributable to dynamic strain aging) but adequate strength is maintained up to 800 C. The reduction in area measured on tensile specimens remained high ({approximately}80%) for test temperatures up to 800 C, in contrast to previous reported results.

  17. Effect of Root Moisture Content and Diameter on Root Tensile Properties

    PubMed Central

    Yang, Yuanjun; Chen, Lihua; Li, Ning; Zhang, Qiufen

    2016-01-01

    The stabilization of slopes by vegetation has been a topical issue for many years. Root mechanical characteristics significantly influence soil reinforcement; therefore it is necessary to research into the indicators of root tensile properties. In this study, we explored the influence of root moisture content on tensile resistance and strength with different root diameters and for different tree species. Betula platyphylla, Quercus mongolica, Pinus tabulaeformis, and Larix gmelinii, the most popular tree species used for slope stabilization in the rocky mountainous areas of northern China, were used in this study. A tensile test was conducted after root samples were grouped by diameter and moisture content. The results showedthat:1) root moisture content had a significant influence on tensile properties; 2) slightly loss of root moisture content could enhance tensile strength, but too much loss of water resulted in weaker capacity for root elongation, and consequently reduced tensile strength; 3) root diameter had a strong positive correlation with tensile resistance; and4) the roots of Betula platyphylla had the best tensile properties when both diameter and moisture content being controlled. These findings improve our understanding of root tensile properties with root size and moisture, and could be useful for slope stabilization using vegetation. PMID:27003872

  18. Effect of Root Moisture Content and Diameter on Root Tensile Properties.

    PubMed

    Yang, Yuanjun; Chen, Lihua; Li, Ning; Zhang, Qiufen

    2016-01-01

    The stabilization of slopes by vegetation has been a topical issue for many years. Root mechanical characteristics significantly influence soil reinforcement; therefore it is necessary to research into the indicators of root tensile properties. In this study, we explored the influence of root moisture content on tensile resistance and strength with different root diameters and for different tree species. Betula platyphylla, Quercus mongolica, Pinus tabulaeformis, and Larix gmelinii, the most popular tree species used for slope stabilization in the rocky mountainous areas of northern China, were used in this study. A tensile test was conducted after root samples were grouped by diameter and moisture content. The results showedthat:1) root moisture content had a significant influence on tensile properties; 2) slightly loss of root moisture content could enhance tensile strength, but too much loss of water resulted in weaker capacity for root elongation, and consequently reduced tensile strength; 3) root diameter had a strong positive correlation with tensile resistance; and4) the roots of Betula platyphylla had the best tensile properties when both diameter and moisture content being controlled. These findings improve our understanding of root tensile properties with root size and moisture, and could be useful for slope stabilization using vegetation. PMID:27003872

  19. Effect of Electron Beam Irradiation on the Tensile Properties of Carbon Nanotubes Sheets and Yarns

    NASA Technical Reports Server (NTRS)

    Williams, Tiffany S.; Miller, Sandi G.; Baker, James S.; McCorkle, Linda S.; Meador, Michael A.

    2013-01-01

    Carbon nanotube sheets and yarns were irradiated using electron beam (e-beam) energy to determine the effect of irradiation dose on the tensile properties. Results showed that a slight change in tensile strength occurred after irradiating as-received CNT sheets for 20 minutes, and a slight decrease in tensile strength as the irradiation time approached 90 minutes. On the other hand, the addition of small molecules to the CNT sheet surface had a greater effect on the tensile properties of e-beam irradiated CNT sheets. Some functionalized CNT sheets displayed up to a 57% increase in tensile strength following 90 minutes of e-beam exposure. In addition, as-received CNT yarns showed a significant increase in tensile strength as the irradiation time increased.

  20. Space environmental effects on graphite-epoxy compressive properties and epoxy tensile properties

    NASA Technical Reports Server (NTRS)

    Fox, Derek J.; Sykes, George F., Jr.; Herakovich, Carl T.

    1987-01-01

    This study characterizes the effects of electron radiation and temperature on a graphite-epoxy composite material. Compressive properties of the T300/934 material system were obtained at -250 F (-157 C), room temperature, and 250 F (121 C). Tensile specimens of the Fiberite 934 epoxy resin were fabricated and tested at room temperature and 250 F (121 C). Testing was conducted in the baseline (nonirradiated) and irradiated conditions. The radiation exposure was designed to simulate 30 year, worst-case exposure in geosynchronous Earth orbit. Mechanical properties tended to degrade at elevated temperature and improve at cryogenic temperature. Irradiation generally degraded properties at all temperatures.

  1. Test system accurately determines tensile properties of irradiated metals at cryogenic temperatures

    NASA Technical Reports Server (NTRS)

    Levine, P. J.; Skalka, R. J.; Vandergrift, E. F.

    1967-01-01

    Modified testing system determines tensile properties of irradiated brittle-type metals at cryogenic temperatures. The system includes a lightweight cryostat, split-screw grips, a universal joint, and a special temperature control system.

  2. Tensile properties of Fe-16 at. % Al alloys

    SciTech Connect

    Sikka, V.K.

    1995-02-01

    A newly developed melting method for Fe-16 at. % Al alloy (FAPY) is described. Tensile data on the air-induction-melted (AIM) and vacuum-induction-melted (VIM) heats of FAPY after identical processing are presented. Optical, scanning electron micrographs (SEM), and microprobe analysis were carried out to explain the lower room-temperature ductility and more scatter in the data for the AIM material as opposed to the VIM material.

  3. High-temperature tensile properties of fiber reinforced reaction bonded silicon nitride

    NASA Technical Reports Server (NTRS)

    Jablonski, David A.; Bhatt, Ramakrishna T.

    1990-01-01

    Measurements of tensile properties of unidirectional silicon carbide fiber-reinforced reaction-bonded silicon nitride (SiC/RBSN) composite specimens were carried out in air at 25, 1300, and 1500 C, using a new testing technique and a specially designed gripping system that minimizes bending moment and assures that failure always occurred in the gage section. The material was found to display metallike stress-strain behavior at all temperatures tested, and a noncatastrophic failure beyond the matrix fracture. The tensile properties were found to be temperature dependent, with the values of the ultimate tensile strength decreasing with temperature, from 543 MPa at 25 C to 169 at 1500 C.

  4. Microstructure and tensile properties of tungsten at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Shen, Tielong; Dai, Yong; Lee, Yongjoong

    2016-01-01

    In order to support the development of the 5 MW spallation target for the European Spallation Source, the effect of fabrication process on microstructure, ductile-to-brittle transition temperature (DBTT), tensile and fracture behaviour of powder-metallurgy pure tungsten materials has been investigated. A hot-rolled (HR) tungsten piece of 12 mm thickness and a hot-forged (HF) piece of about 80 mm thickness were used to simulate the thin and thick blocks in the target. The two tungsten pieces were characterized with metallography analysis, hardness measurement and tensile testing. The HR piece exhibits an anisotropic grain structure with an average size of about 330 × 140 × 40 μm in rolling, long transverse and short transverse (thickness) directions. The HF piece possesses a bimodal grain structure with about 310 × 170 × 70 μm grain size in deformed part and about 25 μm sized grains remained from sintering process. Hardness (HV0.2) of the HR piece is slightly greater than that of the HF one. The ductility of the HR tungsten specimens is greater than that of the HF tungsten. For the HF tungsten piece, specimens with small grains in gauge section manifest lower ductility but higher strength. The DBTT evaluated from the tensile results is 250-300 °C for the HR tungsten and about 350 °C for the HF tungsten.

  5. Effects of Effective Dendrite Size on Dynamic Tensile Properties of Ti-Based Amorphous Matrix Composites

    NASA Astrophysics Data System (ADS)

    Jeon, Changwoo; Park, Jaeyeong; Kim, Choongnyun Paul; Kim, Hyoung Seop; Lee, Sunghak

    2016-04-01

    In this study, dynamic tensile properties of dendrite-containing Ti-based amorphous matrix composites were examined, and effects of dendrite size on dynamic deformation were investigated. The composites contained 73 to 76 vol pct of dendrites whose effective sizes were varied from 63 to 103 μm. The dynamic tensile test results indicated that the ultimate tensile strength increased up to 1.25 GPa, whereas the elongation decreased to 1 pct, although the overall strength and elongation trends followed those of the quasi-static tensile test. According to the observation of dynamic tensile deformation behavior, very few deformation bands were observed beneath the fracture surface in the composite containing large dendrites. In the composite containing small dendrites, deformation bands initiated inside small dendrites propagated into adjacent dendrites through the amorphous matrix, and were crossly intersect perpendicularly in widely deformed areas, which beneficially worked for elongation as well as strength.

  6. Tensile Properties of Poly (N-vinyl caprolactam) Gels

    NASA Technical Reports Server (NTRS)

    Morgret, Leslie D.; Hinkley, Jeffrey A.

    2004-01-01

    N-vinyl caprolactam was copolymerized with ethylene glycol dimethacrylate using a free-radical initiator in alcohol/water solution. The resulting gels were thermally-responsive in water, undergoing an approximate fivefold reversible volume shrinkage between room temperature and ca. 50 C. Tensile testing showed that the stress-strain behavior was qualitatively different in the collapsed state above the temperature-induced transition. At the higher temperature, gels were stiffer, more ductile, and showed greater time dependence. Implications for the design of gel actuators are briefly discussed.

  7. Apparatus for measuring tensile and compressive properties of solid materials at cryogenic temperatures

    DOEpatents

    Gonczy, John D.; Markley, Finley W.; McCaw, William R.; Niemann, Ralph C.

    1992-01-01

    An apparatus for evaluating the tensile and compressive properties of material samples at very low or cryogenic temperatures employs a stationary frame and a dewar mounted below the frame. A pair of coaxial cylindrical tubes extend downward towards the bottom of the dewar. A compressive or tensile load is generated hydraulically and is transmitted by the inner tube to the material sample. The material sample is located near the bottom of the dewar in a liquid refrigerant bath. The apparatus employs a displacement measuring device, such as a linear variable differential transformer, to measure the deformation of the material sample relative to the amount of compressive or tensile force applied to the sample.

  8. Establishing Correlations for Predicting Tensile Properties Based on the Shear Punch Test and Vickers Microhardness data

    NASA Astrophysics Data System (ADS)

    Milot, Timothy S.

    A series of mechanical tests was performed on a matrix of pressure vessel alloys to establish correlations between shear punch tests (SPT), microhardness (Hv), and tensile data. The purpose is to estimate tensile properties from SPT and Hv data. Small specimen testing is central to characterization of irradiation-induced changes in alloys used for nuclear applications. SPT have the potential for estimating tensile yield and ultimate strengths, strain hardening and ductility data, by using TEM disks, for example. Additional insight into SPT was gained by performing finite element analysis (FEA) simulations.

  9. Correlation of tensile and shear strengths of metals with their friction properties

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Buckley, D. H.

    1982-01-01

    The relation between the theoretical tensile and the shear strengths and the friction properties of metals in contact with diamond, boron nitride, silicon carbide, manganese-zinc ferrite, and the metals themselves in vacuum was investigated. The relationship between the actual shear strength and the friction properties of the metal was also investigated. An estimate of the theoretical uniaxial tensile strength was obtained in terms of the equilibrium surface energy, interplanar spacing of the planes perpendicular to the tensile axis, and the Young's modulus of elasticity. An estimate of the theoretical shear strength for metals was obtained from the shear modulus, the repeat distance of atoms in the direction of shear of the metal and the interplanar spacing of the shear planes. The coefficient of friction for metals was found to be related to the theoretical tensile, theoretical shear, and actual shear strengths of metals. The higher the strength of the metal, the lower the coefficient of friction.

  10. Tensile and creep properties of reduced activation ferritic-martensitic steel for fusion energy application

    NASA Astrophysics Data System (ADS)

    Mathew, M. D.; Vanaja, J.; Laha, K.; Varaprasad Reddy, G.; Chandravathi, K. S.; Bhanu Sankara Rao, K.

    2011-10-01

    Tensile and creep properties of a reduced activation ferritic-martensitic (RAFM) steel for Indian Test Blanket Module (TBM) to be tested in ITER have been evaluated. The tensile strength was found to decrease with temperature; the rate of decrease being slower in the intermediate temperature range of 450-650 K. Tensile ductility of the steel decreased with increase in temperature up to 650 K, followed by a rapid increase beyond 650 K. Creep studies have been carried out at 773, 823 and 873 K over a stress range of 100-300 MPa. The variation of minimum creep rate with applied stress followed a power law, ɛ = Aσ n. The ' n' value decreased with increase in temperature. The creep rupture life was found to relate inversely with minimum creep rate through the Monkman-Grant relation, t r · ɛ = constant. The tensile and creep properties of the steel were comparable with those of Eurofer 97.

  11. Tensile Properties, Ferrite Contents, and Specimen Heating of Stainless Steels in Cryogenic Gas Tests

    NASA Astrophysics Data System (ADS)

    Ogata, T.; Yuri, T.; Ono, Y.

    2006-03-01

    We performed tensile tests at cryogenic temperatures below 77 K and in helium gas environment for SUS 304L and SUS 316L in order to obtain basic data of mechanical properties of the materials for liquid hydrogen tank service. We evaluate tensile curves, tensile properties, ferrite contents, mode of deformation and/or fracture, and specimen heating during the testing at 4 to 77 K. For both SUS 304L and 316L, tensile strength shows a small peak around 10 K, and specimen heating decreases above 30 K. The volume fraction of α-phase increases continuously up to 70 % with plastic strain, at approximately 15 % plastic strain for 304L and up to 35 % for 316L. There was almost no clear influence of testing temperature on strain-induced martensitic transformation at the cryogenic temperatures.

  12. Effect of irradiation on the tensile properties of niobium-base alloys

    SciTech Connect

    Grossbeck, M.L.; Heestand, R.L.; Atkin, S.D.

    1986-11-01

    The alloys Nb-1Zr and PWC-11 (Nb-1Zr-0.1C) were selected as prime candidate alloys for the SP-100 reactor. Since the mechanical properties of niobium alloys irradiated to end-of-life exposure levels of about 2 x 10SW neutrons/mS (E > 0.1 MeV) at temperatures above 1300 K were not available, an irradiation experiment (B-350) in EBR-II was conducted. Irradiation creep, impact properties, bending fatigue, and tensile properties were investigated; however, only tensile properties will be reported in this paper. The tensile properties were studied since they easily reveal the common irradiation phenomena of hardening and embrittlement. Most attention was directed to testing at the irradiation temperature. Further testing was conducted at lower temperatures in order to scope the behavior of the alloys in cooldown conditions.

  13. Preparation and tensile properties of DD5 single crystal castings

    NASA Astrophysics Data System (ADS)

    Liang, Xiang-feng; Zhao, Yu-tao; Jia, Zhi-hong; Zhang, Chi

    2016-06-01

    The preparation procedure of DD5 single crystal castings was optimized. The microstructure characteristics of DD5 single crystal superalloy were investigated by microstructure observation and segregation behavior examination. The results show that the grain orientation is optimized by constraining the spiral crystallizer in [001] orientation and spatial scale. Also, the γ' phase of inter-dendrites is larger and more irregular than that in dendrite arms. High temperature tensile tests of DD5 single crystal castings exhibit that the peak stress increases with increasing temperature, while the area reduction shows an opposite trend, when the temperature is below 800°C; meanwhile, when the temperature is between 800°C and 1000°C, the fracture stress of the alloy is the same as the peak stress. The fracture mode changes from shear to ductile with increasing temperature from 600°C and 1000°C.

  14. Characteristics of the tensile mechanical properties of fresh and dry forewings of beetles.

    PubMed

    Tuo, Wanyong; Chen, Jinxiang; Wu, Zhishen; Xie, Juan; Wang, Yong

    2016-08-01

    Based on a tensile experiment and observations by scanning electron microscopy (SEM), this study demonstrated the characteristics of the tensile mechanical properties of the fresh and dry forewings of two types of beetles. The results revealed obvious differences in the tensile fracture morphologies and characteristics of the tensile mechanical properties of fresh and dry forewings of Cybister tripunctatus Olivier and Allomyrina dichotoma. For fresh forewings of these two types of beetles, a viscous, flow-like, polymer matrix plastic deformation was observed on the fracture surfaces, with soft morphologies and many fibers being pulled out, whereas on the dry forewings, the tensile fracture surfaces were straightforward, and there were no features resembling those found on the fresh forewings. The fresh forewings exhibited a greater fracture strain than the dry forewings, which was caused by the relative slippage of hydroxyl inter-chain bonds due to the presence of water in the fibers and proteins in the fresh forewings. Our study is the first to demonstrate the phenomenon of sudden stress drops caused by the fracturing of the lower skin because the lower skin fractured before the forewings of A. dichotoma reached their ultimate tensile strength. We also investigated the reasons underlying this phenomenon. This research provides a much better understanding of the mechanical properties of beetle forewings and facilitates the correct selection of study objects for biomimetic materials and development of the corresponding applications. PMID:27157727

  15. Microstructure-Tensile Properties Correlation for the Ti-6Al-4V Titanium Alloy

    NASA Astrophysics Data System (ADS)

    Shi, Xiaohui; Zeng, Weidong; Sun, Yu; Han, Yuanfei; Zhao, Yongqing; Guo, Ping

    2015-04-01

    Finding the quantitative microstructure-tensile properties correlations is the key to achieve performance optimization for various materials. However, it is extremely difficult due to their non-linear and highly interactive interrelations. In the present investigation, the lamellar microstructure features-tensile properties correlations of the Ti-6Al-4V alloy are studied using an error back-propagation artificial neural network (ANN-BP) model. Forty-eight thermomechanical treatments were conducted to prepare the Ti-6Al-4V alloy with different lamellar microstructure features. In the proposed model, the input variables are microstructure features including the α platelet thickness, colony size, and β grain size, which were extracted using Image Pro Plus software. The output variables are the tensile properties, including ultimate tensile strength, yield strength, elongation, and reduction of area. Fourteen hidden-layer neurons which can make ANN-BP model present the most excellent performance were applied. The training results show that all the relative errors between the predicted and experimental values are within 6%, which means that the trained ANN-BP model is capable of providing precise prediction of the tensile properties for Ti-6Al-4V alloy. Based on the corresponding relations between the tensile properties predicted by ANN-BP model and the lamellar microstructure features, it can be found that the yield strength decreases with increasing α platelet thickness continuously. However, the α platelet thickness exerts influence on the elongation in a more complicated way. In addition, for a given α platelet thickness, the yield strength and the elongation both increase with decreasing β grain size and colony size. In general, the β grain size and colony size play a more important role in affecting the tensile properties of Ti-6Al-4V alloy than the α platelet thickness.

  16. 48 CFR 28.203-3 - Acceptance of real property.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Acceptance of real property. 28.203-3 Section 28.203-3 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION... Acceptance of real property. (a) Whenever a bond with a security interest in real property is submitted,...

  17. 48 CFR 28.203-3 - Acceptance of real property.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Acceptance of real property. 28.203-3 Section 28.203-3 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION... Acceptance of real property. (a) Whenever a bond with a security interest in real property is submitted,...

  18. Effect of Strain-Induced Martensite on Tensile Properties and Hydrogen Embrittlement of 304 Stainless Steel

    NASA Astrophysics Data System (ADS)

    Kim, Young Suk; Bak, Sang Hwan; Kim, Sung Soo

    2016-01-01

    Room temperature tensile tests have been conducted at different strain rates ranging from 2 × 10-6 to 1 × 10-2/s on hydrogen-free and hydrogen-charged 304 stainless steel (SS). Using a ferritescope and neutron diffraction, the amount of strain-induced martensite (SIM) has been in situ measured at the center region of the gage section of the tensile specimens or ex situ measured on the fractured tensile specimens. The ductility, tensile stress, hardness, and the amount of SIM increase with decreasing strain rate in hydrogen-free 304 SS and decrease in hydrogen-charged one. Specifically, SIM that forms during tensile tests is beneficial in increasing the ductility, strain hardening, and tensile stress of 304 SS, irrespective of the presence of hydrogen. A correlation of the tensile properties of hydrogen-free and hydrogen-charged 304 SS and the amount of SIM shows that hydrogen suppresses the formation of SIM in hydrogen-charged 304 SS, leading to a ductility loss and localized brittle fracture. Consequently, we demonstrate that hydrogen embrittlement of 304 SS is related to hydrogen-suppressed formation of SIM, corresponding to the disordered phase, according to our proposition. Compelling evidence is provided by the observations of the increased lattice expansion of martensite with decreasing strain rate in hydrogen-free 304 SS and its lattice contraction in hydrogen-charged one.

  19. Tensile properties influencing variables in eutectic Al-Si casting alloys

    SciTech Connect

    Hafiz, M.F. . Dept. of Mechanical Engineering); Kobayashi, Toshiro . Dept. of Production Systems Engineering)

    1994-09-15

    Efforts to identify and characterize the physical properties of aluminum castings alloys are envisaged to lead to a new guideline from which the mechanical behavior of these alloys can be accurately predicted. For aluminum-silicon (Al-Si) casting alloys the tensile properties of a specific composition are observed to vary depending on the production parameters. The difference in the tensile properties appears to be mainly due to the microstructural features concomitant with the imposed production parameters. The present study aims to identify, quantitatively, the tensile properties influencing variables in high purity eutectic Al-Si casting alloy produced under a variety of solidification cooling rate with different strontium (Sr) additions, as a modifying agent. The correlation between the fracture characteristics and the microstructures has also been investigated.

  20. Sample selection, preparation methods, and the apparent tensile properties of silkworm (B. mori) cocoon silk.

    PubMed

    Reed, Emily J; Bianchini, Lindsay L; Viney, Christopher

    2012-06-01

    Reported literature values of the tensile properties of natural silk cover a wide range. While much of this inconsistency is the result of variability that is intrinsic to silk, some is also a consequence of differences in the way that silk is prepared for tensile tests. Here we explore how measured mechanical properties of Bombyx mori cocoon silk are affected by two intrinsic factors (the location from which the silk is collected within the cocoon, and the color of the silk), and two extrinsic factors (the storage conditions prior to testing, and different styles of reeling the fiber). We find that extrinsic and therefore controllable factors can affect the properties more than the intrinsic ones studied. Our results suggest that enhanced inter-laboratory collaborations, that lead to standardized sample collection, handling, and storage protocols prior to mechanical testing, would help to decrease unnecessary (and complicating) variation in reported tensile properties. PMID:22057343

  1. The effect of structure on tensile properties of directionally solidified Zn-based alloys

    NASA Astrophysics Data System (ADS)

    Ares, A. E.; Schvezov, C. E.

    2011-03-01

    The main objective of this study was to measure thermal (cooling rates, temperature gradients and velocities of the liquidus and solidus isotherms), structural (grain size and primary and secondary dendritic arm spacings) and tensile parameters (maximum tensile strength (MTS), yield strength (YS) and ultimate tensile strength (UTS)) in zinc-aluminum (ZA) hypoeutectic (Zn-3 wt%Al) and hypereutectic (Zn-10 wt%Al, Zn-15 wt%Al, Zn-20 wt%Al, Zn-30 wt%Al, Zn-37 wt%Al and Zn-50 wt%Al) alloys directionally solidified, which present columnar, equiaxed and columnar-to-equiaxed transition (CET) structures. The different types of structures were analyzed with optical and Scanning Electron Microscopy (SEM). Correlations between temperature gradient, cooling rate, local solidification time, grain size and dendritic spacings and tensile tests parameters are presented and discussed. The results show the influence of concentration, microstructural arrangement and thermal conditions on the mechanical properties during the solidification process.

  2. Tensile and creep properties of titanium-vanadium, titanium-molybdenum, and titanium-niobium alloys

    NASA Technical Reports Server (NTRS)

    Gray, H. R.

    1975-01-01

    Tensile and creep properties of experimental beta-titanium alloys were determined. Titanium-vanadium alloys had substantially greater tensile and creep strength than the titanium-niobium and titanium-molybdenum alloys tested. Specific tensile strengths of several titanium-vanadium-aluminum-silicon alloys were equivalent or superior to those of commercial titanium alloys to temperatures of 650 C. The Ti-50V-3Al-1Si alloy had the best balance of tensile strength, creep strength, and metallurgical stability. Its 500 C creep strength was far superior to that of a widely used commercial titanium alloy, Ti-6Al-4V, and almost equivalent to that of newly developed commercial titanium alloys.

  3. Ball Indentation Studies on the Effect of Nitrogen on the Tensile Properties of 316LN SS

    NASA Astrophysics Data System (ADS)

    Mathew, M. D.; Ganesh Kumar, J.; Ganesan, V.; Laha, K.

    2015-12-01

    Type 316L(N) stainless steel (SS) containing 0.02-0.03 wt% carbon and 0.06-0.08 wt% nitrogen is used as the major structural material for the components of fast reactors. Research is underway to improve the high-temperature mechanical properties of 316LN SS by increasing the nitrogen content in the steel above the level of 0.08 wt%. In this investigation, ball indentation (BI) technique was used to evaluate the effect of nitrogen content on the tensile properties of 316LN SS. BI tests were conducted on four different heats of 316LN SS containing 0.07, 0.11, 0.14 and 0.22 wt% nitrogen in the temperature range 300-923 K. The tensile properties such as yield strength and ultimate tensile strength increased with increase in nitrogen content at all the investigated temperatures. These results were consistent with the corresponding uniaxial tensile test results. These studies showed that BI technique can be used to optimize the chemical composition during alloy development by evaluating tensile properties with minimum volume of material.

  4. Elevated-temperature tensile and creep properties of several ferritic stainless steels

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. D.

    1977-01-01

    The elevated-temperature mechanical properties of several ferritic stainless steels were determined. The alloys evaluated included Armco 18SR, GE 1541, and NASA-18T-A. Tensile and creep strength properties at 1073 and 1273 K and residual room temperature tensile properties after creep testing were measured. In addition, 1273 K tensile and creep tests and residual property testing were conducted with Armco 18SR and GE 1541 which were exposed for 200 hours to a severe oxidizing environment in automotive thermal reactors. Aside from the residual tensile properties for Armco 18SR, prior exposure did not affect the mechanical properties of either alloy. The 1273 K creep strength parallel to the sheet-rolling direction was similar for all three alloys. At 1073 K, NASA-18T-A had better creep strength than either Armco 18SR or GE 1541. NASA-18T-A possesses better residual properties after creep testing than either Armco 18SR or Ge 1541.

  5. 10 CFR 603.550 - Acceptability of intellectual property.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Acceptability of intellectual property. 603.550 Section 603.550 Energy DEPARTMENT OF ENERGY (CONTINUED) ASSISTANCE REGULATIONS TECHNOLOGY INVESTMENT AGREEMENTS Pre-Award Business Evaluation Cost Sharing § 603.550 Acceptability of intellectual property. (a) In most instances, the contracting officer...

  6. Tensile properties of V-(4-5)Cr-(4-5)Ti alloys

    SciTech Connect

    Chung, H.M.; Nowicki, L.; Busch, D.; Smith, D.L.

    1996-04-01

    The current focus of the U.S program of research on V-base alloys is on V-(4-5)Cr(4-5)Ti that contains 500-1000 wppm Si. in this paper, we present experimental results on baseline tensile properties of two laboratory-scale heats of this alloy and of a 500-kg production heat of V-4Cr-4Ti (heat 832665) that were measured at 23-700 C. Both the production- and laboratory scale heats of the reference alloy V-4Cr-4Ti exhibited excellent tensile properties at temperatures up to {approx}650{degrees}C.

  7. Influences of Welding Processes on Microstructure, Hardness, and Tensile Properties of AZ31B Magnesium Alloy

    NASA Astrophysics Data System (ADS)

    Padmanaban, G.; Balasubramanian, V.; Sarin Sundar, J. K.

    2010-03-01

    This article reports the influences of welding processes such as gas tungsten arc welding (GTAW), friction stir welding (FSW), and laser beam welding (LBW) on tensile properties of AZ31B magnesium alloy. The lowest hardness distribution profile (LHDP) is constructed across the weld section to identify the fracture path. From this investigation, it is found that LBW joints exhibited superior tensile properties compared to GTAW and FSW joints and this is mainly due to the formation of very fine grains in the fusion zone and absence of heat-affected zone (HAZ).

  8. Impact tensile properties and strength development mechanism of glass for reinforcement fiber

    NASA Astrophysics Data System (ADS)

    Kim, T.; Oshima, K.; Kawada, H.

    2013-07-01

    In this study, impact tensile properties of E-glass were investigated by fiber bundle testing under a high strain rate. The impact tests were performed employing two types of experiments. One is the tension-type split Hopkinson pressure bar system, and the other is the universal high-speed tensile-testing machine. As the results, it was found that not only the tensile strength but also the fracture strain of E-glass fiber improved with the strain rate. The absorbed strain energy of this material significantly increased. It was also found that the degree of the strain rate dependency of E-glass fibers on the tensile strength was varied according to fiber diameter. As for the strain rate dependency of the glass fiber under tensile loading condition, change of the small crack-propagation behaviour was considered to clarify the development of the fiber strength. The tensile fiber strength was estimated by employing the numerical simulation based on the slow crack-growth model (SCG). Through the parametric study against the coefficient of the crack propagation rate, the numerical estimation value was obtained for the various testing conditions. It was concluded that the slow crack-growth behaviour in the glass fiber was an essential for the increase in the strength of this material.

  9. Tensile Properties of Polymeric Matrix Composites Subjected to Cryogenic Environments

    NASA Technical Reports Server (NTRS)

    Whitley, Karen S.; Gates, Thomas S.

    2004-01-01

    Polymer matrix composites (PMC s) have seen limited use as structural materials in cryogenic environments. One reason for the limited use of PMC s in cryogenic structures is a design philosophy that typically requires a large, validated database of material properties in order to ensure a reliable and defect free structure. It is the intent of this paper to provide an initial set of mechanical properties developed from experimental data of an advanced PMC (IM7/PETI-5) exposed to cryogenic temperatures and mechanical loading. The application of this data is to assist in the materials down-select and design of cryogenic fuel tanks for future reusable space vehicles. The details of the material system, test program, and experimental methods will be outlined. Tension modulus and strength were measured at room temperature, -196 C, and -269 C on five different laminates. These properties were also tested after aging at -186 C with and without loading applied. Microcracking was observed in one laminate.

  10. Tensile and impact properties of General Atomics 832864 heat of V-4Cr-4Ti alloy

    SciTech Connect

    Tsai, H.; Nowicki, L.J.; Gazda, J.; Billone, M.C.; Smith, D.L.; Johnson, W.R.; Trester, P.

    1998-09-01

    A 1300-kg heat of V-4Cr-4Ti alloy was procured by General Atomics (GA) for the DIII-D radiative divertor program. To determine the mechanical properties of this alloy, tensile and Charpy tests were conducted on specimens prepared from pieces of 4.8-mm-thick as-rolled plates, a major product form for the DIII-D application. The tensile tests were conducted at three temperatures, 26, 280 and 380 C, the last two being the anticipated peak temperatures during DIII-D boronization and postvent bake-out, respectively. Results from these tests show that the tensile and impact properties of the 832864 heat are comparable to those of the other smaller V-(4-5)Cr-(4-5)Ti alloy heats previously developed by the US Fusion Materials Program and that scale-up of vanadium alloy production can be successfully achieved as long as reasonable process control is implemented.

  11. Tensile and Impact Properties of Thermoplastic Natural Rubber (TPNR) Filled with Carbon Nanotubes (MWNTs)

    NASA Astrophysics Data System (ADS)

    Tarawneh, Mou'ad. A.; Ahmad, Sahrim Hj.; Yahya, S. Y.; Rasid, Rozaidi; Hock, Yew Chin; Halim, Hazwani Binti

    2010-07-01

    This paper discusses the effect of multi-walled carbon nanotubes (MWNT) on the tensile and impact properties of thermoplastic natural rubber (TPNR) nanocomposite. The nanocomposite was prepared using melt blending method. MWNT were added to improve the mechanical properties of MWNTs/TPNR composites at different compositions which is 1, 3, 5, and 7 wt.%. The result of tensile test showed that tensile strength and Young's modulus increase in the presence of nanotubes and maximum value are obtained with 3 wt.% of MWNTs. On other hand, higher MWNTs concentration has caused the formation of aggregates. The elongation at break considerably decreased with increasing the percentage of MWNTs. The maximum impact strength is recorded with 5 wt.% of MWNTs. SEM micrograph has confirmed the homogenous dispersion of MWNTs in the TPNR matrix and promoted strong interfacial adhesion between MWNTs and the matrix which is improved mechanical significantly.

  12. The Tensile Properties of Advanced Nickel-Base Disk Superalloys During Quenching Heat Treatments

    NASA Technical Reports Server (NTRS)

    Gabb, Timothy P.; Gayda, John; Kantzos, Pete T.; Biles, Tiffany; Konkel, William

    2001-01-01

    There is a need to increase the temperature capabilities of superalloy turbine disks. This would allow full utilization of higher temperature combustor and airfoil concepts under development. One approach to meet this goal is to modify the processing and chemistry of advanced alloys, while preserving the ability to use rapid cooling supersolvus heat treatments to achieve coarse grain, fine gamma prime microstructures. An important step in this effort is to understand the key high temperature tensile properties of advanced alloys as they exist during supersolvus heat treatments. This could help in projecting cracking tendencies of disks during quenches from supersolvus heat treatments. The objective of this study was to examine the tensile properties of two advanced disk superalloys during simulated quenching heat treatments. Specimens were cooled from the solution heat treatment temperatures at controlled rates, interrupted, and immediately tensile tested at various temperatures. The responses and failure modes were compared and related to the quench cracking tendencies of disk forgings.

  13. Tensile properties of an ultrahigh-strength graphite fiber in an epoxy matrix

    NASA Technical Reports Server (NTRS)

    Chiao, T. T.; Hamstad, M. A.; Jessop, E. S.

    1974-01-01

    The fiber performance and reinforcement potential for fiber composites of a special PAN-based graphite fiber were evaluated by testing the fiber's tensile properties in an epoxy matrix. Representative strand samples were taken from 30 spools of single-end, 1500-filament fiber to make over 5000 fiber/epoxy strand specimens using the filament-winding process. Characteristics studied were fiber uniformity, strength and modulus distributions at room and liquid-nitrogen temperatures, stress-strain behavior, the effect of strain rate on fiber strength, and acoustic emission during tensile loading to failure. The fiber was found to have a 3570-MPa failure stress, a 1.7% failure strain, a 206-GPa modulus, and a density of 1.77 Mg/cu m at 23 C. Liquid-nitrogen temperature and various strain rates had no significant effect on fiber tensile properties.

  14. Mechanical shear and tensile properties of selected biomass stems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lignocellulosic biomass, such as big bluestem, corn stalk, intermediate wheat grass and switchgrass stem are abundant and dominant species in the Midwest region of US. There is a need to understand the mechanical properties for these crops for better handling and processing of the biomass feedstocks...

  15. Influence of crystallization conditions on the tensile properties of radiation crosslinked, vitamin E stabilized UHMWPE.

    PubMed

    George, A; Ngo, H D; Bellare, A

    2014-12-01

    Radiation crosslinking for ultra-high molecular weight polyethylene results in improved wear resistance but a reduction in mechanical properties. Incorporation of vitamin E has been known to decrease the rate of oxidative degradation occurring through radiation crosslinking and prevents the need for post-irradiation melting with subsequent loss of crystallinity. In this study, we aimed to determine the effect of thermal treatments prior to crosslinking on the morphology and tensile properties of vitamin-E-containing polyethylene. Vitamin-E-blended polyethylene was melted and subsequently quenched in ice water in order to induce high rate crystallization. A second group was additionally annealed at 126°C following quenching and all samples were irradiated using electron beam radiation to a dose of 100kGy. The morphology of control, quenched and quench-annealed polyethylene was characterized using small angle x-ray scattering and differential scanning calorimetry. Tensile properties of these polyethylenes were measured before and after radiation crosslinking with equilibrium swelling experiments performed to assess the crosslink density of irradiated samples. This study shows how the tensile properties of polyethylene can be enhanced by varying thermal treatments prior to crosslinking; and thus how it may be possible to offset the reduction in tensile properties afforded by the crosslinking process. PMID:25305634

  16. Intrinsic tensile properties of cocoon silk fibres can be estimated by removing flaws through repeated tensile tests.

    PubMed

    Rajkhowa, Rangam; Kaur, Jasjeet; Wang, Xungai; Batchelor, Warren

    2015-06-01

    Silk fibres from silkworm cocoons have lower strength than spider silk and have received less attention as a source of high-performance fibres. In this work, we have used an innovative procedure to eliminate the flaws gradually of a single fibre specimen by retesting the unbroken portion of the fibre, after each fracture test. This was done multiple times so that the final test may provide the intrinsic fibre strength. During each retest, the fibre specimen began to yield once the failure load of the preceding test was exceeded. For each fibre specimen, a composite curve was constructed from multiple tests. The composite curves and analysis show that strengths of mass-produced Muga and Eri cocoon silk fibres increased from 446 to 618 MPa and from 337 to 452 MPa, respectively. Similarly, their toughness increased from 84 to 136 MJ m(-3) and from 61 to 104 MJ m(-3), respectively. Composite plots produced significantly less inter-specimen variations compared to values from single tests. The fibres with reduced flaws as a result of retests in the tested section have a tensile strength and toughness comparable to naturally spun dragline spider silk with a reported strength of 574 MPa and toughness of 91-158 MJ m(-3), which is used as a benchmark for developing high-performance fibres. This retesting approach is likely to provide useful insights into discrete flaw distributions and intrinsic mechanical properties of other fatigue-resistant materials. PMID:25948613

  17. Intrinsic tensile properties of cocoon silk fibres can be estimated by removing flaws through repeated tensile tests

    PubMed Central

    Rajkhowa, Rangam; Kaur, Jasjeet; Wang, Xungai; Batchelor, Warren

    2015-01-01

    Silk fibres from silkworm cocoons have lower strength than spider silk and have received less attention as a source of high-performance fibres. In this work, we have used an innovative procedure to eliminate the flaws gradually of a single fibre specimen by retesting the unbroken portion of the fibre, after each fracture test. This was done multiple times so that the final test may provide the intrinsic fibre strength. During each retest, the fibre specimen began to yield once the failure load of the preceding test was exceeded. For each fibre specimen, a composite curve was constructed from multiple tests. The composite curves and analysis show that strengths of mass-produced Muga and Eri cocoon silk fibres increased from 446 to 618 MPa and from 337 to 452 MPa, respectively. Similarly, their toughness increased from 84 to 136 MJ m−3 and from 61 to 104 MJ m−3, respectively. Composite plots produced significantly less inter-specimen variations compared to values from single tests. The fibres with reduced flaws as a result of retests in the tested section have a tensile strength and toughness comparable to naturally spun dragline spider silk with a reported strength of 574 MPa and toughness of 91–158 MJ m−3, which is used as a benchmark for developing high-performance fibres. This retesting approach is likely to provide useful insights into discrete flaw distributions and intrinsic mechanical properties of other fatigue-resistant materials. PMID:25948613

  18. Tensile Properties of Al-Cu 206 Cast Alloys with Various Iron Contents

    NASA Astrophysics Data System (ADS)

    Liu, K.; Cao, X.; Chen, X.-G.

    2014-05-01

    The Al-Cu 206 cast alloys with varying alloy compositions ( i.e., different levels of Fe, Mn, and Si) were investigated to evaluate the effect of the iron-rich intermetallics on the tensile properties. It is found that the tensile strength decreases with increasing iron content, but its overall loss is less than 10 pct over the range of 0.15 to 0.5 pct Fe at 0.3 pct Mn and 0.3 pct Si. At similar iron contents, the tensile properties of the alloys with dominant Chinese script iron-rich intermetallics are generally higher than those with the dominant platelet phase. In the solution and artificial overaging condition (T7), the tensile strength of the 206 cast alloys with more than 0.15 pct Fe is satisfactory, but the elongation does not sufficiently meet the minimum requirement of ductility (>7 pct) for critical automotive applications. However, it was found that both the required ductility and tensile strength can be reached at high Fe levels of 0.3 to 0.5 pct for the alloys with well-controlled alloy chemistry and microstructure in the solution and natural aging condition (T4), reinforcing the motivation for developing recyclable high-iron Al-Cu 206 cast alloys.

  19. Effect of particle size and volume fraction on tensile properties of fly ash/polyurea composites

    NASA Astrophysics Data System (ADS)

    Qiao, Jing; Schaaf, Kristin; Amirkhizi, Alireza V.; Nemat-Nasser, Siavouche

    2010-04-01

    Fly ash, which consists of hollow particles with porous shells, was introduced into polyurea elastomer. A one-step method was chosen to fabricate pure polyurea and the polyurea matrix for the composites based on Isonate® 2143L (diisocyanate) and Versalink® P-1000 (diamine). Scanning electron microscopy was used to observe the fracture surfaces of the composites. Particle size and volume fraction were varied to study their effects on the tensile properties of the composites. The tensile properties of the pure polyurea and fly ash/polyurea (FA/PU) composites were tested using an Instron load frame with a 1 kN Interface model 1500ASK-200 load cell. Results showed that fly ash particles were distributed homogeneously in the polyurea matrix, and all of the composites displayed rubber-like tensile behavior similar to that of pure polyurea. The tensile strength of the composites was influenced by both the fly ash size and the volume fraction. Compared to the largest particle size or the highest volume fraction, an increase in tensile strength was achieved by reducing particle size and/or volume fraction. The strain at break of the composites also increased by using fine particles. In addition, the composites filled with 20% fly ash became softer. These samples showed lower plateau strength and larger strain at break than the other composites.

  20. Characteristics of thermoplastic sugar palm Starch/Agar blend: Thermal, tensile, and physical properties.

    PubMed

    Jumaidin, R; Sapuan, S M; Jawaid, M; Ishak, M R; Sahari, J

    2016-08-01

    The aim of this work is to study the behavior of biodegradable sugar palm starch (SPS) based thermoplastic containing agar in the range of 10-40wt%. The thermoplastics were melt-mixed and then hot pressed at 140°C for 10min. SEM investigation showed good miscibility between SPS and agar. FT-IR analysis confirmed that SPS and agar were compatible and inter-molecular hydrogen bonds existed between them. Incorporation of agar increased the thermoplastic starch tensile properties (Young's modulus and tensile strength). The thermal stability and moisture uptake increased with increasing agar content. The present work shows that starch-based thermoplastics with 30wt% agar content have the highest tensile strength. Higher content of agar (40wt%) resulted to more rough cleavage fracture and slight decrease in the tensile strength. In conclusion, the addition of agar improved the thermal and tensile properties of thermoplastic SPS which widened the potential application of this eco-friendly material. The most promising applications for this eco-friendly material are short-life products such as packaging, container, tray, etc. PMID:27177458

  1. Tensile properties of helical auxetic structures: A numerical study

    NASA Astrophysics Data System (ADS)

    Wright, J. R.; Sloan, M. R.; Evans, K. E.

    2010-08-01

    This paper discusses a helical auxetic structure which has a diverse range of practical applications. The mechanical properties of the system can be determined by particular combinations of geometry and component material properties; finite element analysis is used to investigate the static behavior of these structures under tension. Modeling criteria are determined and design issues are discussed. A description of the different strain-dependent mechanical phases is provided. It is shown that the stiffnesses of the component fibers and the initial helical wrap angle are critical design parameters, and that strain-dependent changes in cross-section must be taken into consideration: we observe that the structures exhibit nonlinear behavior due to nonzero component Poisson's ratios. Negative Poisson's ratios for the helical structures as low as -5 are shown. While we focus here on the structure as a yarn our findings are, in principle, scaleable.

  2. The Cryogenic Tensile Properties of an Extruded Aluminum-Beryllium Alloy

    NASA Technical Reports Server (NTRS)

    Gamwell, W. R.

    2002-01-01

    Basic mechanical properties; i.e., ultimate tensile strength, yield strength, percent elongation, and elastic modulus, were obtained for the aluminum-beryllium alloy, AlBeMet162, at cryogenic (-195.5 C (-320 F) and -252.8 C (-423 F)) temperatures. The material evaluated was purchased to the requirements of SAE-AMS7912, "Aluminum-Beryllium Alloy, Extrusions."

  3. Effect of dynamically charged helium on tensile properties of V-4Cr-4Ti

    SciTech Connect

    Chung, H.M.; Loomis, B.A.; Nowicki, L.; Smith, D.L.

    1995-04-01

    The objective of this work is to determine the effect of displacement damage and dynamically charged helium on tensile properties of V-4Cr-4Ti alloy irradiated to 18-31 dpa at 425-600{degree}C in the Dynamic Helium Charging Experiment (DHCE).

  4. Wear-Lines and Split-Lines of Human Patellar Cartilage: Relation to Tensile Biomechanical Properties

    PubMed Central

    Bae, Won C.; Wong, Van W.; Hwang, Jennifer; Antonacci, Jennifer M.; Nugent-Derfus, Gayle E.; Blewis, Megan E.; Temple-Wong, Michele M.; Sah, Robert L.

    2008-01-01

    Background Articular cartilage undergoes age-associated degeneration, resulting in both structural and functional biomechanical changes. At early stages of degeneration, wear-lines develop in the general direction of joint movement. With aging, cartilage exhibits a decrease in tensile modulus. The tensile modulus of cartilage has also been related to the orientation of the collagen network, as revealed by split-lines. Objective To determine the relative contribution of wear-line and split-line orientation on the tensile biomechanical properties of human patellar cartilage from different depths. Methods In human patellar cartilage, wear- and split-lines are aligned parallel to each other at the proximal facet, and perpendicular to each other at the medial facet. Using superficial, middle, and deep cartilage sections from these two sites, tensile samples were prepared in two orthogonal orientations. Thus, for each depth, there were four groups of samples, with their long axes were aligned either parallel or perpendicular to wear-line direction and also aligned parallel or perpendicular to split-line direction. Uniaxial tensile tests were performed to assess equilibrium and ramp moduli. Results Tensile equilibrium modulus varied with wear-line orientation (p<0.05) and depth (p<0.001), in an interactive manner (p<0.05), and tended to vary with split-line orientation (p=0.16). In the superficial layer, equilibrium and ramp modulus was higher when the samples were loaded parallel to wear-lines (p<0.05). Conclusion These results indicate that mild wear (i.e., wear-line formation) at the articular surface has deleterious functional effects on articular cartilage and represents an early aging associated degenerative change. The identification and recognition of functional biomechanical consequences of wear-lines is useful for planning and interpreting tensile biomechanical tests in human articular cartilage. PMID:18248747

  5. Dynamic tensile material properties of human pelvic cortical bone.

    PubMed

    Kemper, Andrew R; McNally, Craig; Duma, Stefan M

    2008-01-01

    IIn order for finite element models of the human body to predict pelvic injuries accurately, the appropriate material properties must be applied. Therefore, the purpose of this study was to quantify the dynamic material properties of human pelvic cortical bone in tension. In order to accomplish this, a total of 20 tension coupon specimens were obtained from four regions of four human cadaver pelves: anterior ilium wing, posterior ilium wing, superior pubic ramus, and ischium body. For the anterior and posterior regions of the ilium wing, samples were taken in two orientations to investigate any direction dependence. A high-rate servo-hydraulic Material Testing System (MTS) with a custom slack adaptor was used to apply tension loads to failure at a constant loading rate of 0.5 strains/s. The horizontally oriented anterior ilium specimens were found to have a significantly larger ultimate stress (p=0.02), ultimate strain (p>0.01), and modulus (p=0.02) than the vertically oriented anterior ilium specimens. There were no significant differences in ultimate stress (p=0.27), ultimate strain (p=0.85), or modulus (p=0.87) found between horizontally oriented and vertically oriented posterior ilium specimens. However, additional testing should be conducted at specimen orientation 45 degree from the orientations used in the current study to further investigate the effect of specimen orientation on the posterior portion of the ilium wing. There were no significant differences in ultimate stress (p=0.79), ultimate strain (p=0.31), or modulus (p=0.15) found between the superior pubic ramus and ischium body specimens. However, the statistical comparison between superior pubic ramus and ischium body specimens was considered weak due to the limited samples and large variation between subjects. PMID:19141951

  6. Tensile properties of reduced activation Fe-9Cr-2W steels after FFTF irradiation

    NASA Astrophysics Data System (ADS)

    Kurishita, H.; Kayano, H.; Narui, M.; Kimura, A.; Hamilton, M. L.; Gelles, D. S.

    1994-09-01

    In order to develop radiation resistant steels with reduced activation for fusion reactor applications, the effect of fast neutron irradiation was investigated on the tensile properties of five types of Fe-9Cr-2W martensitic steel with and without small additions of boron, yttrium and aluminum. Miniature tensile specimens of the steels were irradiated to 28 dpa at 663 K and 33-35 dpa at 703, 793 and 873 K in the Fast Flux Test Facility (FFTF) and were deformed at temperatures between 300 and 873 K. The yield and ultimate tensile stresses were not significantly affected by the irradiations, but the total elongation was considerably decreased by the irradiation at 663 K. The reduction in elongation depended strongly on the test temperature with a maximum at around 673 K. The addition of yttrium alone tended to increase the high temperature strength, while the simultaneous addition of yttrium and aluminum tended to decrease the total elongation.

  7. Effects of Plasma Nitriding on the Tensile Properties of Al-Mg-Si

    NASA Astrophysics Data System (ADS)

    Ghauri, I. M.; Ahmad, R.; Mubarik, F. E.; Afzal, Naveed; Ahmed, Sajjad; Ayub, R.

    2012-07-01

    Effects of plasma nitriding on the tensile behavior of Al-Mg-Si alloy were investigated in this study. The specimens were nitrided at 70 W input pulsed DC power at 1 mbar pressure of nitrogen for 4 h using glow discharge plasma. The formation of aluminum nitride layer on the specimen's surface was confirmed by the XRD analysis. Stress-strain curves of both un-nitrided and nitrided specimens were obtained using Universal Testing Machine. The comparison of these curves reveals that yield stress, ultimate tensile stress, percentage elongation, and stress relaxation rate decrease after plasma nitriding. The changes in the tensile properties after nitriding have been correlated with the changes in the microstructure of the specimens as observed using scanning electron microscope.

  8. Apparatus for measuring tensile and compressive properties of solid materials at cryogenic temperatures

    DOEpatents

    Gonczy, J.D.; Markley, F.W.; McCaw, W.R.; Niemann, R.C.

    1992-04-21

    An apparatus for evaluating the tensile and compressive properties of material samples at very low or cryogenic temperatures employs a stationary frame and a dewar mounted below the frame. A pair of coaxial cylindrical tubes extend downward towards the bottom of the dewar. A compressive or tensile load is generated hydraulically and is transmitted by the inner tube to the material sample. The material sample is located near the bottom of the dewar in a liquid refrigerant bath. The apparatus employs a displacement measuring device, such as a linear variable differential transformer, to measure the deformation of the material sample relative to the amount of compressive or tensile force applied to the sample. 7 figs.

  9. Annealing and Test Temperature Dependence of Tensile Properties of UNS N04400 Alloy

    NASA Astrophysics Data System (ADS)

    Afzal, Naveed; Ahmad, R.; Akhtar, Tanveer; Ayub, R.; Ghauri, I. M.

    2013-07-01

    Effects of annealing and test temperatures on the tensile behavior of UNS N04400 alloy have been examined. The specimens were annealed at 800, 1000, and 1200 °C for 4 h under vacuum in a muffle furnace. Stress-strain curves of the specimens were obtained in the temperature range 25-300 °C using a universal testing machine fitted with a thermostatic chamber. The results indicate that the yield strength (YS), ultimate tensile strength (UTS), and percentage elongation of the specimens decrease with increase of annealing temperature. By increasing the test temperature, the YS and UTS decrease, whereas the percentage elongation initially decreases with increase of test temperature from 25 to 100 °C and then increases with further increasing the temperature up to 300 °C. The changes in the tensile properties of the alloy are associated with the post-annealing microstructure and modes of fracture.

  10. Tensile property of H13 die steel with convex-shaped biomimetic surface

    NASA Astrophysics Data System (ADS)

    Zhang, Z. H.; Zhou, H.; Ren, L. Q.; Tong, X.; Shan, H. Y.; Cao, Y.

    2007-09-01

    The H13 steel specimens with non-smooth surface were fabricated by biomimetic method and laser technique, and the effect of these biomimetic surfaces on the tensile properties was investigated. The results indicated that the biomimetic surface has an advantageous effect on improving the tensile properties of H13 steel. As the area ratio occupied by non-smooth units on the biomimetic surface grows to 26.7%, the ultimate tensile strength (UTS) and 0.2% yield strength (YS) of materials linearly increase by about 8.4% and 17.2%, respectively. The elongation to fracture of materials reaches to the peak value of about 41.3% at the point of 17.1% area ratio, and further heightening the area ratio can result in a reduced ductility relative to this peak value. This improvement of tensile properties can be attributed to the combined effects of the microstructure characteristics within the unit zone and the unit-distribution features on the surface. Meanwhile, the regressed relation equations of UTS, YS and elongation regarding the area ratio were obtained via statistical theory. The tests of regression significance showed that the confidence of these equations achieved 99% above.

  11. Tensile properties of V-Cr-Ti alloys after exposure in hydrogen-containing environments

    SciTech Connect

    Natesan, K.; Soppett, W.K.

    1998-03-01

    A systematic study has been initiated to evaluate the performance of several V-Cr-Ti alloys after exposure to environments containing hydrogen at various partial pressures. The goal is to correlate the chemistry of the exposure environment with the hydrogen uptake in the samples and its influence on the microstructure and tensile properties of the alloys. At present, four heats of alloys (BL-63, BL-71, and T87, plus 44 from General Atomics) are being evaluated. Other variables of interest are the effect of initial grain size on hydrogen uptake and tensile properties, and the synergistic effects of oxygen and hydrogen on the tensile behavior of the alloys. Experiments conducted thus far on specimens of various V-Cr-Ti alloys exposed to pH{sub 2} levels of 0.01 and 3 {times} 10{sup {minus}6} torr showed negligible effect of H{sub 2} on either maximum engineering stress of uniform/total elongation. Further, preliminary tests on specimens annealed at different temperatures showed that grain size variation by a factor of {approx}2 had a negligible effect on tensile properties.

  12. Tensile Properties of the Deep Transverse Metatarsal Ligament in Hallux Valgus

    PubMed Central

    Abdalbary, Sahar Ahmed; Elshaarawy, Ehab A.A.; Khalid, Bahaa E.A.

    2016-01-01

    Abstract The deep transverse metatarsal ligament (DTML) connects the neighboring 2 metatarsal heads and is one of the stabilizers connecting the lateral sesamoid and second metatarsal head. In this study, we aimed to determine the tensile properties of the DTML in normal specimens and to compare these results with hallux valgus specimens. We hypothesized that the tensile properties of the DTML would be different between the 2 groups of specimens. The DTML in the first interspace was dissected from 12 fresh frozen human cadaveric specimens. Six cadavers had bilateral hallux valgus and the other 6 cadavers had normal feet. The initial length (L0) and cross-sectional area (A0) of the DTML were measured using a digital caliper, and tensile tests with load failure were performed using a material testing machine. There were significant between-groups differences in the initial length (L0) P = 0.009 and cross-sectional area (A0) of the DTML P = 0.007. There were also significant between-groups differences for maximum force (N) P = 0.004, maximum distance (mm) P = 0.005, maximum stress (N/mm2) P = 0.003, and maximum strain (%) P = 0.006. The DTML is an anatomical structure for which the tensile properties differ in hallux valgus. PMID:26937914

  13. Kenaf-glass fiber reinforced unsaturated polyester hybrid composites: Tensile properties

    NASA Astrophysics Data System (ADS)

    Zhafer, S. F.; Rozyanty, A. R.; Shahnaz, S. B. S.; Musa, L.; Zuliahani, A.

    2016-07-01

    The use of natural fibers in composite is rising in recent years due their lightweight, non-abrasive, combustible, non-toxic, low cost and biodegradable properties. However, in comparison with synthetic fibers, the mechanical properties of natural fibers are lower. Therefore, the inclusion of synthetic fibers could improve the mechanical performance of natural fiber based composites. In this study, kenaf bast fiber and glass fiber at different weight percentage loading were used as reinforcement to produce hybrid composites. Unsaturated polyester (UP) resin was used as matrix and hand lay-up process was performed to apply the UP resin on the hybrid kenaf bast/glass fiber composite. Effect of different fiber loading on tensile strength, tensile modulus and elongation at break of the hybrid composite was studied. It has been found that the highest value of tensile strength and modulus was achieved at 10 wt.% kenaf/10 wt.% glass fiber loading. It was concluded that addition of glass fiber has improved the tensile properties of kenaf bast fiber based UP composites.

  14. Tensile properties of vanadium alloys irradiated at 390{degrees}C in EBR-II

    SciTech Connect

    Chung, H.M.; Tsai, H.C.; Nowicki, L.J.

    1997-08-01

    Vanadium alloys were irradiated in Li-bonded stainless steel capsules to {approx}390{degrees}C in the EBR-II X-530 experiment. This report presents results of postirradiation tests of tensile properties of two large-scale (100 and 500 kg) heats of V-4Cr-Ti and laboratory (15-30 kg) heats of boron-doped V-4Cr-4Ti, V-8Cr-6Ti, V-5Ti, and V-3Ti-1Si alloys. Tensile specimens, divided into two groups, were irradiated in two different capsules under nominally similar conditions. The 500-kg heat (No. 832665) and the 100-kg heat (VX-8) of V-4Cr-4Ti irradiated in one of the subcapsules exhibited complete loss of work-hardening capability, which was manifested by very low uniform plastic strain. In contrast, the 100-kg heat of V-4Cr-4Ti irradiated in another subcapsule exhibited good tensile properties (uniform plastic strain 2.8-4.0%). A laboratory heat of V-3Ti-1Si irradiated in the latter subcapsule also exhibited good tensile properties. These results indicate that work-hardening capability at low irradiation temperatures varies significantly from heat to heat and is influenced by nominally small differences in irradiation conditions.

  15. Microstructures and tensile properties of as-cast iron-aluminide alloys

    SciTech Connect

    Viswanathan, S.; McKamey, C.G.; Maziasz, P.J.; Sikka, V.K.

    1994-09-01

    Room-temperature tensile properties of as-cast Fe{sub 3}Al, Fe{sub 3}Al with chromium, and Fe{sub 3}Al-based FA-129 alloy have been investigated. Tensile properties have been obtained in air in the as-cast condition for all three alloys. Samples of FA-129 alloy have also been tested in oxygen and water vapor environments, and after homogenization at 700, 900, and 1200C. Transmission electron microscopy has been used to characterize ordered phases and optical metallography and scanning electron microscopy have been used to characterize the microstructure and fracture morphology. Tensile properties in the as-cast condition exhibited an environmental effect; tensile ductilities in an oxygen atmosphere were greater than those obtained in laboratory air. Homogenized samples of FA-129 alloy exhibited almost twice the ductility of the as-cast condition. Results indicate that the low ductility of as-cast Fe{sub 3}Al-based alloys may be related to the relatively large grain size in the as-cast condition and the presence of the DO{sub 3} ordered phase. Microstructural characterization of the homogenized samples and comparison of the as-cast and homogenized microstructures may provide a clue to the poor ductility in the as-cast condition.

  16. Tensile and creep rupture properties of (16) uncoated and (2) coated engineering alloys at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Fritz, L. J.; Koster, W. P.

    1977-01-01

    Sixteen test materials were supplied by NASA-Lewis Research Center as wrought bar or cast remelt stock. The cast remelt stock was cast into test blanks with two such materials being also evaluated after Jocoat coating was applied. Mechanical properties evaluated included tensile, modulus of elasticity, Poisson's Ratio, creep properties and creep rupture strength. Tests were conducted at temperatures applicable to the service temperature of the various alloys. This range extended from room temperature to 1000 C.

  17. Report on thermal aging effects on tensile properties of ferritic-martensitic steels.

    SciTech Connect

    Li, M.; Soppet, W.K.; Rink, D.L.; Listwan, J.T.; Natesan, K.

    2012-05-10

    This report provides an update on the evaluation of thermal-aging induced degradation of tensile properties of advanced ferritic-martensitic steels. The report is the first deliverable (level 3) in FY11 (M3A11AN04030103), under the Work Package A-11AN040301, 'Advanced Alloy Testing' performed by Argonne National Laboratory, as part of Advanced Structural Materials Program for the Advanced Reactor Concepts. This work package supports the advanced structural materials development by providing tensile data on aged alloys and a mechanistic model, validated by experiments, with a predictive capability on long-term performance. The scope of work is to evaluate the effect of thermal aging on the tensile properties of advanced alloys such as ferritic-martensitic steels, mod.9Cr-1Mo, NF616, and advanced austenitic stainless steel, HT-UPS. The aging experiments have been conducted over a temperature of 550-750 C for various time periods to simulate the microstructural changes in the alloys as a function of time at temperature. In addition, a mechanistic model based on thermodynamics and kinetics has been used to address the changes in microstructure of the alloys as a function of time and temperature, which is developed in the companion work package at ANL. The focus of this project is advanced alloy testing and understanding the effects of long-term thermal aging on the tensile properties. Advanced materials examined in this project include ferritic-martensitic steels mod.9Cr-1Mo and NF616, and austenitic steel, HT-UPS. The report summarizes the tensile testing results of thermally-aged mod.9Cr-1Mo, NF616 H1 and NF616 H2 ferritic-martensitic steels. NF616 H1 and NF616 H2 experienced different thermal-mechanical treatments before thermal aging experiments. NF616 H1 was normalized and tempered, and NF616 H2 was normalized and tempered and cold-rolled. By examining these two heats, we evaluated the effects of thermal-mechanical treatments on material microstructures and

  18. Tensile properties of human knee joint cartilage: I. Influence of ionic conditions, weight bearing, and fibrillation on the tensile modulus.

    PubMed

    Akizuki, S; Mow, V C; Müller, F; Pita, J C; Howell, D S; Manicourt, D H

    1986-01-01

    The flow-independent (intrinsic) tensile modulus of the extracellular matrix of human knee joint cartilage has been measured for normal, fibrillated, and osteoarthritic (removed from total knee joint replacements) cartilage. The modulus was determined in our isometric tensile apparatus and measured at equilibrium. We found a linear equilibrium stress-strain behavior up to approximately 15% strain. The modulus was measured for tissues from the high and low weight-bearing areas of the joint surfaces, the medial femoral condyle and lateral patello femoral groove, and from different zones (surface, subsurface, middle, and middle-deep) within the tissue. For all specimens, the intrinsic tensile modulus was always less than 30 MPa. Tissues from low weight-bearing areas (LWA) are stiffer than those from high weight-bearing areas (HWA). The tensile modulus of the ECM correlates strongly with the collagen/proteoglycan ratio; it is higher for LWA than for HWA. Osteoarthritic cartilage from total knee replacement procedures has a tensile stiffness less than 2 MPa. PMID:3783297

  19. Effect of initial orientation on the tensile properties of commercially pure titanium

    NASA Astrophysics Data System (ADS)

    Sinha, Subhasis; Ghosh, Atasi; Gurao, N. P.

    2016-05-01

    Effect of crystallographic texture on uniaxial tensile deformation of commercially pure titanium was studied using in situ as well as post-mortem electron backscatter diffraction and elastoplastic self-consistent simulations. Correlation of mechanical properties and strain hardening response with deformation micromechanisms like different modes of slip and twinning was established. Tensile specimens were machined along rolling direction in the plane perpendicular to normal and transverse direction (sample A and C, respectively) as well as along transverse direction in the plane normal to rolling direction (sample B) to obtain different initial texture from cold rolled and annealed plate of commercially pure titanium. Sample B showed higher strength but lower strain hardening rate and ductility than the orientations A and C. It showed extension twinning with lateral thickening while the other samples showed coexistence of extension and contraction twinning. Schmid factor accounted for most of the observed twinning although some contraction twinning in sample A is attributed to the effect of internal stresses. A combination of in situ tensile test in a field emission gun scanning electron microscope with electron backscatter diffraction facility and elastoplastic self-consistent simulations aid in obtaining high-fidelity Voce hardening parameters for different slip and twinning systems in commercially pure titanium. The variation in tensile properties can be explained on the basis of propensity of twinning which tends to provide strain hardening at lower strain but contributes to failure at higher strain.

  20. Effect of ultrasonic treatment on tensile properties of PLA/LNR/NiZn ferrite nanocomposite

    SciTech Connect

    Shahdan, Dalila; Ahmad, Sahrim Hj.; Flaifel, Moayad Husein

    2013-11-27

    The influence of sonication treatment time on the morphological and mechanical properties of LNR/PLA composite impregnated with different filler loadings of NiZn ferrite nanoparticles was investigated. The nanocomposite was prepared using melt blending method with assistance of ultrasonic treatment of 0, 1 and 2 hrs. Structural characterization of the nanocomposites was examined using scanning electron microscopy (SEM) with their elemental composition being confirmed by energy dispersive X-ray spectroscopy (EDX). The tensile properties of LNR/PLA composite treated with different ultrasonication times have improved with increasing magnetic nanofiller signature in the nanocomposite. Further, the optimum sonication time of 1 hr was found to produce nanocomposite with maximum tensile properties.

  1. Tensile properties of monofilament and multifilament composites with different titanium matrices

    SciTech Connect

    Dudek, H.J.; Leucht, R.; Werner, A.

    1996-05-15

    In many cases the tensile properties of fibers coated with matrix can give first leads to the properties of multifilament composites with the same matrix material. In the present investigation the authors compare the tensile test results of the monofilament composites with those of multifilament composites of the same matrix material. For the matrix different titanium alloys and titanium aluminides are used and the matrix ductility is varied by the oxygen content. Their results demonstrate that beside the interface the matrix ductility mainly determines the properties of the mono- and multifilament composites. In the present investigation SiC-SCS-6 fibers (Textron Inc.) were coated with different titanium alloys and titanium aluminides using magnetron sputtering.

  2. Characterization of cure in model photocrosslinking acrylate systems: Relationships among tensile properties, Tg and ultraviolet dose

    SciTech Connect

    Rakas, M.A.

    1996-10-01

    The extent of cure of a thermosetting polymer is governed largely by polymerization kinetics and the difference between the polymerization temperature and the material`s ultimate glass transition temperature (Tg). For prepolymers which cure when exposed to ultraviolet (UV) radiation, other factors which strongly determine the extent of cure are the UV intensity and exposure time, and the interrelationship between the optical absorbance of the photoinitiator (PI) and the rate of formation of excited state PI radicals. Beers` Law can be used to understand the relationship between the PI`s molar absorptivity, its concentration, and adhesive film thickness. Many adhesives users are more concerned with bulk properties such as tensile modulus and Tg rather than a numerical measurement of degree of cure. Therefore, this research employed model acrylate formulations and determined changes in tensile properties and Tg as a function of film thickness and UV dose. These results enabled correlation of bulk and photoinitiator properties.

  3. Comparison of the Tensile, Creep, and Rupture Strength Properties of Stoichiometric SiC Fibers

    NASA Technical Reports Server (NTRS)

    Yun, H. M.; DiCarlo, J. A.

    1999-01-01

    Tensile strength, creep strength, and rupture strength properties were measured for the following types of polymer-derived stoichiometric SiC fibers: Hi-Nicalon Type S from Nippon Carbon, Tyranno SA from Ube, and Sylramic from Dow Corning. Also included in this study were an earlier version of the SA fiber plus two recent developmental versions of the Sylramic fiber. The tensile strength measurements were made at room temperature on as-received fibers and on fibers after high-temperature inert exposure. The creep-rupture property data were obtained at 1400 deg C in air as well as, argon. Some fiber types showed strong effects of environment on their strength properties. These results are compared and discussed in terms of underlying mechanisms and implications for ceramic composites.

  4. Structure and tensile properties evaluation of samples produced by Fused Deposition Modeling

    NASA Astrophysics Data System (ADS)

    Gajdoš, Ivan; Slota, Ján; Spišák, Emil; Jachowicz, Tomasz; Tor-Swiatek, Aneta

    2016-05-01

    This paper presents the result of a study evaluating the influence of alternative path generation strategy on structure and some mechanical properties of parts produced by Fused Deposition Modeling (FDM) technology. Several scientific investigations focused on resolving issues in FDM parts by modifying a path generation strategy to optimize its mechanical properties. In this study, an alternative strategy was proposed with the intention of minimizing internal voids and, thus, to improve mechanical properties. Polycarbonate samples made by this alternative path generation strategy were subjected to tensile strength test and metro-tomography structure evaluation. The results reveal that the structure observed on build models differs from a structure expected from path generation predicted by software Insight 9.1. This difference affected the tensile strength of samples.

  5. Tensile Properties and Deformation Characteristics of a Ni-Fe-Base Superalloy for Steam Boiler Applications

    NASA Astrophysics Data System (ADS)

    Zhong, Zhihong; Gu, Yuefeng; Yuan, Yong; Shi, Zhan

    2014-01-01

    Ni-Fe-base superalloys due to their good manufacturability and low cost are the proper candidates for boiler materials in advanced power plants. The major concerns with Ni-Fe-base superalloys are the insufficient mechanical properties at elevated temperatures. In this paper, tensile properties, deformation, and fracture characteristics of a Ni-Fe-base superalloy primarily strengthened by γ' precipitates have been investigated from room temperature to 1073 K (800 °C). The results showed a gradual decrease in the strength up to about 973 K (700 °C) followed by a rapid drop above this temperature and a ductility minimum at around 973 K (700 °C). The fracture surfaces were studied using scanning electron microscopy and the deformation mechanisms were determined by the observation of deformed microstructures using transmission electron microscopy. An attempt has been made to correlate the tensile properties and fracture characteristics at different temperatures with the observed deformation mechanisms.

  6. Tensile Properties and Structure of Several Superalloys after Long- Term Exposure to LiF and Vacuum at 1173 K

    NASA Astrophysics Data System (ADS)

    Whittenberger, J. D.

    1995-12-01

    The use of the solid- to- liquid phase transformation of LiF to store thermal energy is under consideration for a space- based solar dynamic system. Although advantageous in terms of its energy density, the melting point of this salt (1121K) is beyond the commonly accepted upper- use temperature of 1100 K for chromium- bearing superalloys in vacuum. However, one commercially available nickel- base superalloy (Hastelloy B- 2) is chromium free; unfortunately, because of its high molybdenum content, this alloy can form phases that cause high- temperature embrittlement. To test the suitability of Hastelloy B- 2, it has been exposed to molten LiF, its vapor and vacuum at 1173 K for 2500, 5000, and 10 h. For control, the chromium- containing cobalt- base Haynes alloy 188 and nickel- base Haynes alloy 230 were also exposed to LiF and vacuum at 1173 K for 5000 h. Neither LiF nor vacuum exposures had any significant effect on Hastelloy B- 2 in terms of microstructural surface damage or weight change. Measurement of the post exposure tensile properties of Hastelloy B- 2, nevertheless, revealed low tensile ductility at 1050 K. Such embrittlement and low strength at elevated temperatures appear to preclude the use of Hastelloy B- 2 as a containment material for LiF. Little evidence of significant attack by LiF was seen in either of the chromium- containing superalloys; however, considerable weight loss and near- surface microstructural damage occurred in both alloys exposed to vacuum. Although measurement of the post exposure room-temperature tensile properties of Haynes alloys 188 and 230 revealed no significant loss of strength or ductility, the severe degree of microstructural damage found in unshielded alloys exposed to vacuum indicates that chromium-bearing superalloys might also be unsuitable for prolonged containment of LiF in space above 1100 K. Keywords

  7. Dependence of electronic properties of germanium on the in-plane biaxial tensile strains

    NASA Astrophysics Data System (ADS)

    Yang, C. H.; Yu, Z. Y.; Liu, Y. M.; Lu, P. F.; Gao, T.; Li, M.; Manzoor, S.

    2013-10-01

    The hybrid HSE06 functional with the spin-orbit coupling effects is used to calculate the habituation of the electronic properties of Ge on the (0 0 1), (1 1 1), (1 0 1) in-plane biaxial tensile strains (IPBTSs). Our motivation is to explore the nature of electronic properties of tensile-strained Ge on different substrate orientations. The calculated results demonstrate that one of the most effective and practical approaches for transforming Ge into a direct transition semiconductor is to introduce (0 0 1) IPBTS to Ge. At 2.3% (0 0 1) IPBTS, Ge becomes a direct bandgap semiconductor with 0.53 eV band gap, in good agreement with the previous theoretical and experimental results. We find that the (1 1 1) and (1 0 1) IPBTSs are not efficient since the shear strain and inner displacement of atoms introduced by them quickly decrease the indirect gap of Ge. By investigating the dependence of valence band spin-orbit splitting on strain, we prove that the dependency relationship and the coupled ways between the valence-band states of tensile-strained Ge are closely related to the symmetry of strain tensor, i.e., the symmetry of the substrate orientation. The first- and second-order coefficients describing the dependence of indirect gap, direct gap, the valence band spin-orbit coupling splitting, and heavy-hole-light-hole splitting of Ge on IPBTSs have been obtained by the least squares polynomial fitting. These coefficients are significant to quantitatively modulate the electronic properties of Ge by tensile strain and design tensile-strained Ge devices by semiconductor epitaxial technique.

  8. Effect of Thermal Exposure on the Tensile Properties of Aluminum Alloys for Elevated Temperature Service

    NASA Technical Reports Server (NTRS)

    Edahl, Robert A., Jr.; Domack, Marcia

    2004-01-01

    Tensile properties were evaluated for four aluminum alloys that are candidates for airframe applications on high speed transport aircraft. These alloys included the Al-Cu-Mg-Ag alloys C415 and C416 and the Al-Cu-Li-Mg-Ag alloys RX818 and ML377. The Al-Cu-Mg alloys CM001, which was used on the Concorde SST, and 1143, which was modified from the alloy used on the TU144 Russian supersonic aircraft, were tested for comparison. The alloys were subjected to thermal exposure at 200 F, 225 F and 275 F for times up to 30,000 hours. Tensile tests were performed on thermally-exposed and as-received material at -65 F, room temperature, 200 F, 225 F and 275 F. All four candidate alloys showed significant tensile property improvements over CM001 and 1143. Room temperature yield strengths of the candidate alloys were at least 20% greater than for CM001 and 1143, for both the as-received and thermally-exposed conditions. The strength levels of alloy RX818 were the highest of all materials investigated, and were 5-10% higher than for ML377, C415 and C416 for the as-received condition and after 5,000 hours thermal exposure. RX818 was removed from this study after 5,000 hours exposure due to poor fracture toughness performance observed in a parallel study. After 30,000 hours exposure at 200 F and 225 F, the alloys C415, C416 and ML377 showed minor decreases in yield strength, tensile strength and elongation when compared to the as-received properties. Reductions in tensile strength from the as-received values were up to 25% for alloys C415, C416 and ML377 after 15,000 hours exposure at 275 F.

  9. Tensile and electrical properties of high-strength high-conductivity copper alloys

    SciTech Connect

    Zinkle, S.J.; Eatherly, W.S.

    1998-09-01

    Electrical conductivity and tensile properties have been measured on an extruded and annealed CuCrNb dispersion strengthened copper alloy which has been developed for demanding aerospace high heat flux applications. The properties of this alloy are somewhat inferior to GlidCop dispersion strengthened copper and prime-aged CuCrZr over the temperature range of 20--500 C. However, if the property degradation in CuCrZr due to joining operations and the anisotropic properties of GlidCop in the short transverse direction are taken into consideration, CuCrNb may be a suitable alternative material for high heat flux structural applications in fusion energy devices. The electrical conductivity and tensile properties of CuCrZr that was solution annealed and then simultaneously aged and diffusion bonded are also summarized. A severe reduction in tensile elongation is observed in the diffusion bonded joint, particularly if a thin copper shim is not placed in the diffusion bondline.

  10. Tensile and burning properties of clay/phenolic/GF composite and its application

    NASA Astrophysics Data System (ADS)

    Diharjo, Kuncoro; Armunanto, V. Bram; Kristiawan, S. Adi

    2016-03-01

    Composite material has been widely used in automotive due to its properties can be improved by combining with reinforcement, like fiber and particle to enhance mechanical properties and burning resistance. This study aims to investigate the tensile and burning properties of hybrid composite combining glass fiber and clay in phenolic resin. The clay was produced from roof tile rejected by tile industries in Sokka, Kebumen, Indonesia. The composite was made using a press mold method for different number of laminates and orientation of woven-roving-glass-fiber/ WRGF (0/90 and ±45), and the total volume fraction of fiber and clay is constant 40%. The specimens were tested using universal testing machine for tensile properties and burning tests apparatus for burning resistance (time to ignite/ TTI and burning rate/ BR). The enhancing of the Clay/Penolic/GF composite can be performed by the increasing of GF laminates, and the composite with 0/90 orientation of WRGF has higher tensile strength and modulus compared to that with ±45 orientation of WRGF. Both composite with 0/90 and ±45 orientation of WRGF have similar burning resistance (TTI and BR) and the composite containing 13 laminates of WR-GF shows the best burning resistance. According to these properties, this composite has good opportunity to be applied as car body panels or other structure in industries due to save weight and high burning resistance.

  11. Tensile Properties and Fracture Behavior of Different Carbon Nanotube-Grafted Polyacrylonitrile-Based Carbon Fibers

    NASA Astrophysics Data System (ADS)

    Naito, Kimiyoshi

    2014-11-01

    The tensile properties and fracture behavior of different carbon nanotube (CNT)-grafted polyacrylonitrile-based (T1000GB) single carbon fibers were investigated. Grafting of CNTs was achieved via chemical vapor deposition (CVD). When Fe(C5H5)2 (also applied via CVD) was used as the catalyst, the tensile strength and Weibull modulus of the carbon fibers were improved, possibly due to the growth of dense CNT networks on the carbon fibers, which may have led to a reduction in the number of strength-limiting defects. Separately, at lower concentrations of an Fe(NO3)3·9H2O catalyst in ethanol, which was applied via dipping, the tensile strength of CNT-grafted fibers was nearly identical to that of the as-received fibers, although the Weibull modulus was higher. For higher concentrations of the Fe(NO3)3·9H2O catalyst, however, the tensile strength and the Weibull modulus were lower than those for the as-received material. Although the density of the CNT network increased with the concentration of the Fe(NO3)3·9H2O catalyst in the ethanol solution, heating of the ethanolic Fe(NO3)3·9H2O catalyst solution generated nitric acid (HNO3) due to decomposition, which damaged the fiber surfaces, resulting in an increase in the number of flaws and consequently a reduction in the tensile strength. Therefore, the tensile strength and Weibull modulus of CNT-grafted carbon fibers vary due to the combination of these effects and as a function of the catalyst concentration.

  12. Tensile properties of SiC/aluminum filamentary composites - Thermal degradation effects

    NASA Technical Reports Server (NTRS)

    Skinner, A.; Koczak, M. J.; Lawley, A.

    1982-01-01

    Aluminium metal matrix composites with a low cost fiber, e.g. SiC, provide for an attractive combination of high elastic modulus and longitudinal strengths coupled with a low density. SiC (volume fraction 0.55)-aluminum (6061) systems have been studied in order to optimize fiber composite strength and processing parameters. A comparison of two SiC/aluminum composites produced by AVCO and DWA is provided. Fiber properties are shown to alter composite tensile properties and fracture morphology. The room temperature tensile strengths appear to be insensitive to thermal exposures at 500 C up to 150 h. The elastic modulus of the composites also appears to be stable up to 400 C, however variations in the loss modulus are apparent. The fracture morphology reflects the quality of the interfacial bond, fiber strengths and fiber processing.

  13. Transverse tensile and stress rupture properties of gamma/gamma prime-delta directionally solidified eutectic

    NASA Technical Reports Server (NTRS)

    Gray, H. H.

    1976-01-01

    Tensile and stress rupture properties were determined primarily at 760 C for specimens oriented at various angles (0 deg, 10 deg, 45 deg, and 90 deg) from the solidification direction of bars and/or slabs of the Ni-20Cb-6Cr-2.5A (gamma/gamma prime-delta) eutectic. Threaded-head specimens yielded longer rupture lives with significantly less scatter than did tapered-head specimens. Miniature specimens are suitable for determining traverse tensile and rupture properties of 1.2 centimeter diameter bar stock. The 300 hour rupture stress at 760 C for specimens oriented at 10 deg from the solidification direction was reduced from 740 to 460 MPa, and to 230 MPa for material oriented at either 45 deg or 90 deg.

  14. Effect of Hybrid Surface Modifications on Tensile Properties of Polyacrylonitrile- and Pitch-Based Carbon Fibers

    NASA Astrophysics Data System (ADS)

    Naito, Kimiyoshi

    2016-05-01

    Recent interest has emerged in techniques that modify the surfaces of carbon fibers, such as carbon nanotube (CNT) grafting or polymer coating. Hybridization of these surface modifications has the potential to generate highly tunable, high-performance materials. In this study, the mechanical properties of surface-modified polyacrylonitrile (PAN)-based and pitch-based carbon fibers were investigated. Single-filament tensile tests were performed for fibers modified by CNT grafting, dipped polyimide coating, high-temperature vapor deposition polymerized polyimide coating, grafting-dipping hybridization, and grafting-vapor deposition hybridization. The Weibull statistical distributions of the tensile strengths of the surface-modified PAN- and pitch-based carbon fibers were examined. All surface modifications, especially hybrid modifications, improved the tensile strengths and Weibull moduli of the carbon fibers. The results exhibited a linear relationship between the Weibull modulus and average tensile strength on a log-log scale for all surface-modified PAN- and pitch-based carbon fibers.

  15. High temperature tensile properties and fracture characteristics of bimodal 12Cr-ODS steel

    NASA Astrophysics Data System (ADS)

    Chauhan, Ankur; Litvinov, Dimitri; Aktaa, Jarir

    2016-01-01

    This article describes the tensile properties and fracture characteristics of a 12Cr oxide dispersion strengthened (ODS) ferritic steel with unique elongated bimodal grain size distribution. The tensile tests were carried out at four different temperatures, ranging from room temperature to 700 °C, at a nominal strain rate of 10-3 s-1. At room temperature the material exhibits a high tensile strength of 1294 MPa and high yield strength of 1200 MPa. At 700 °C, the material still exhibits relatively high tensile strength of 300 MPa. The total elongation-to-failure exceeds 18% over the whole temperature range and has a maximum value of 29% at 600 °C. This superior ductility is attributed to the material's bimodal grain size distribution. In comparison to other commercial, as well as experimental, ODS steels, the material shows an excellent compromise between strength and ductility. The fracture surface studies reveal a change in fracture behavior from a mixed mode fracture at room temperature to fully ductile fracture at 600 °C. At 700 °C, the fracture path changes from intragranular to intergranular fracture, which is associated with a reduced ductility.

  16. Tensile Properties of Polyimide Composites Incorporating Carbon Nanotubes-Grafted and Polyimide-Coated Carbon Fibers

    NASA Astrophysics Data System (ADS)

    Naito, Kimiyoshi

    2014-09-01

    The tensile properties and fracture behavior of polyimide composite bundles incorporating carbon nanotubes-grafted (CNT-grafted) and polyimide-coated (PI-coated) high-tensile-strength polyacrylonitrile (PAN)-based (T1000GB), and high-modulus pitch-based (K13D) carbon fibers were investigated. The CNT were grown on the surface of the carbon fibers by chemical vapor deposition. The pyromellitic dianhydride/4,4'-oxydianiline PI nanolayer coating was deposited on the surface of the carbon fiber by high-temperature vapor deposition polymerization. The results clearly demonstrate that CNT grafting and PI coating were effective for improving the Weibull modulus of T1000GB PAN-based and K13D pitch-based carbon fiber bundle composites. In addition, the average tensile strength of the PI-coated T1000GB carbon fiber bundle composites was also higher than that of the as-received carbon fiber bundle composites, while the average tensile strength of the CNT-grafted T1000GB, K13D, and the PI-coated K13D carbon fiber bundle composites was similar to that of the as-received carbon fiber bundle composites.

  17. Hydrogen Embrittlement Evaluation in Tensile Properties of Stainless Steels at Cryogenic Temperatures

    NASA Astrophysics Data System (ADS)

    Ogata, T.

    2008-03-01

    The advanced design of fuel-cell vehicles requires high-pressure low-temperature hydrogen systems, which in turn requires a high-pressure low-temperature mechanical properties database to address hydrogen embrittlement issues. A very simple and safe mechanical properties testing procedure to evaluate low temperature hydrogen embrittlement has been developed and is reported here. Tensile properties of stainless steel, SUS 304, 304L and 316L, obtained by this simple method are in good agreement with previous data obtained in a high pressure chamber. The effect of hydrogen changed also with the amount of strain-induced martensitic transformation in those steels at low temperatures.

  18. An Assessment of Variability in the Average Tensile Properties of a Melt-Infiltrated SiC/SiC Composite

    NASA Technical Reports Server (NTRS)

    Kalluri, Sreeramesh; Brewer, David N.; Calomino, Anthony M.

    2004-01-01

    Woven SiC/SiC Ceramic Matrix Composites (CMCs), manufactured by the slurry-cast, melt-infiltration process are under consideration as combustor liner materials in aircraft gas turbine engines. Tensile properties (elastic modulus, proportional limit strength, in-plane tensile strength and strain to failure) of the CMC, manufactured during two separate time periods (9/99 and 1/01) were determined at 816 and 1024 C by conducting tensile tests on specimens machined from the CMC plates. A total of 24 tensile tests were conducted for each temperature and CMC variant combination. In this study average tensile properties of the two cMC variants were statistically compared to evaluate significant differences, if any, within the CMC's properties.

  19. Influence of Biochemical Composition on Endplate Cartilage Tensile Properties in the Human Lumbar Spine

    PubMed Central

    Fields, Aaron J.; Rodriguez, David; Gary, Kaitlyn N.; Liebenberg, Ellen C.; Lotz, Jeffrey C.

    2014-01-01

    Endplate cartilage integrity is critical to spine health and is presumably impaired by deterioration in biochemical composition. Yet, quantitative relationships between endplate biochemical composition and biomechanical properties are unavailable. Using endplate cartilage harvested from human lumbar spines (six donors, ages 51–67 years) we showed that endplate biochemical composition has a significant influence on its equilibrium tensile properties and that the presence of endplate damage associates with a diminished composition–function relationship. We found that the equilibrium tensile modulus (5.9±5.7 MPa) correlated significantly with collagen content (559±147 μg/mg dry weight, r2=0.35) and with the collagen/GAG ratio (6.0±2.1, r2=0.58). Accounting for the damage status of the adjacent cartilage improved the latter correlation (r2=0.77) and indicated that samples with adjacent damage such as fissures and avulsions had a diminished modulus–collagen/GAG relationship (p=0.02). Quasi-linear viscoelastic relaxation properties (C, t1, and t2) did not correlate with biochemical composition. We conclude that reduced matrix quantity decreases the equilibrium tensile modulus of human endplate cartilage and that characteristics of biochemical composition that are independent of matrix quantity, that is, characteristics related to matrix quality, may also be important. PMID:24273192

  20. Tensile and tribological properties of high-crystallinity radiation crosslinked UHMWPE

    SciTech Connect

    Bistolfi, Alessandro; Turell, Mary Beth; Lee, Ying-Lung; Bellare, Anuj

    2009-09-02

    Osteolysis due to particulate wear debris associated with ultrahigh molecular weight polyethylene (UHMWPE) components of total joint replacement prostheses has been a major factor determining their in vivo lifetime. In recent years, radiation crosslinking has been employed to decrease wear rates in PE components, especially in acetabular cups of total hip replacement prostheses. A drawback of radiation crosslinking is that it leads to a crosslinked PE (or XPE) with lower mechanical properties compared with uncrosslinked PE. In contrast, high-crystallinity PEs are known to have several mechanical properties higher than conventional PE. In this study, we hypothesized that increasing the crystallinity of radiation crosslinked and remelted XPE would result in an increase in tensile properties without compromising wear resistance. High-pressure crystallization was performed on PE and XPE and analyzed for the resulting morphological alterations using differential scanning calorimeter, low voltage scanning electron microscopy, and ultrasmall angle X-ray scattering. Uniaxial tensile tests showed that high-pressure crystallization increased the tensile modulus and yield stress in both PE and XPE, decreased the ultimate strain and ultimate stress in PE but had no significant effect on ultimate strain or ultimate stress in XPE. Multidirectional wear tests demonstrated that high-pressure crystallization decreased the wear resistance of PE but had no effect on the wear resistance of XPE. In conclusion, this study shows that high-pressure crystallization can be effectively used to increase the crystallinity and modulus of XPE without compromising its superior wear resistance compared with PE.

  1. Tensile Properties and Swelling Behavior of Sealing Rubber Materials Exposed to High-Pressure Hydrogen Gas

    NASA Astrophysics Data System (ADS)

    Yamabe, Junichiro; Nishimura, Shin

    Rubber O-rings exposed to high-pressure hydrogen gas swell, and the volume increase induced by swelling influences tensile properties of the O-rings. Samples of nonfilled (NF), carbon black-filled (CB), and silica-filled (SC) sulfur-vulcanized acrylonitrile-butadiene rubber were exposed to hydrogen at 30 °C and pressures of up to 100 MPa, and the effect of hydrogen exposure on the volume increase, hydrogen content, and tensile properties was investigated. The residual hydrogen content, measured 35 minutes after decompression, increased with increasing hydrogen pressure in the range 0.7-100 MPa for all three samples. In contrast, the volumes of NF, CB, and SC barely changed at pressures below 10 MPa, whereas they increased at pressures above 10 MPa. This nonlinear volume increase is probably related to the free volume of the rubber structure. The volume increase of the CB and SC samples was smaller than that of the NF samples, possibly because of the superior tensile properties of CB and SC. As the volumes of the NF, CB, and SC samples increased, their tensile elastic moduli decreased as a result of a decrease in crosslink density and elongation by volume increase. Although the true fracture stress of NF was barely dependent on the volume of the specimen, those of CB and SC clearly decreased as the volume increased. The decrease in the true fracture stress of CB and SC was related to the volume increase by swelling, showing that the boundary structure between the filler and the rubber matrix was changed by the volume increase.

  2. A comparison of tensile properties of polyester composites reinforced with pineapple leaf fiber and pineapple peduncle fiber

    NASA Astrophysics Data System (ADS)

    Juraidi, J. M.; Shuhairul, N.; Syed Azuan, S. A.; Intan Saffinaz Anuar, Noor

    2013-12-01

    Pineapple fiber which is rich in cellulose, relatively inexpensive, and abundantly available has the potential for polymer reinforcement. This research presents a study of the tensile properties of pineapple leaf fiber and pineapple peduncle fiber reinforced polyester composites. Composites were fabricated using leaf fiber and peduncle fiber with varying fiber length and fiber loading. Both fibers were mixed with polyester composites the various fiber volume fractions of 4, 8 and 12% and with three different fiber lengths of 10, 20 and 30 mm. The composites panels were fabricated using hand lay-out technique. The tensile test was carried out in accordance to ASTM D638. The result showed that pineapple peduncle fiber with 4% fiber volume fraction and fiber length of 30 mm give highest tensile properties. From the overall results, pineapple peduncle fiber shown the higher tensile properties compared to pineapple leaf fiber. It is found that by increasing the fiber volume fraction the tensile properties has significantly decreased but by increasing the fiber length, the tensile properties will be increased proportionally. Minitab software is used to perform the two-way ANOVA analysis to measure the significant. From the analysis done, there is a significant effect of fiber volume fraction and fiber length on the tensile properties.

  3. A Novel Ni-Containing Powder Metallurgy Steel with Ultrahigh Impact, Fatigue, and Tensile Properties

    NASA Astrophysics Data System (ADS)

    Wu, Ming-Wei; Shu, Guo-Jiun; Chang, Shih-Ying; Lin, Bing-Hao

    2014-08-01

    The impact toughness of powder metallurgy (PM) steel is typically inferior, and it is further impaired when the microstructure is strengthened. To formulate a versatile PM steel with superior impact, fatigue, and tensile properties, the influences of various microstructures, including ferrite, pearlite, bainite, and Ni-rich areas, were identified. The correlations between impact toughness with other mechanical properties were also studied. The results demonstrated that ferrite provides more resistance to impact loading than Ni-rich martensite, followed by bainite and pearlite. However, Ni-rich martensite presents the highest transverse rupture strength (TRS), fatigue strength, tensile strength, and hardness, followed by bainite, pearlite, and ferrite. With 74 pct Ni-rich martensite and 14 pct bainite, Fe-3Cr-0.5Mo-4Ni-0.5C steel achieves the optimal combination of impact energy (39 J), TRS (2170 MPa), bending fatigue strength at 2 × 106 cycles (770 MPa), tensile strength (1323 MPa), and apparent hardness (38 HRC). The impact energy of Fe-3Cr-0.5Mo-4Ni-0.5C steel is twice as high as those of the ordinary high-strength PM steels. These findings demonstrate that a high-strength PM steel with high-toughness can be produced by optimized alloy design and microstructure.

  4. Influence of macrostructure on tensile properties of multipass SAW C-Mn steel deposits

    NASA Astrophysics Data System (ADS)

    Yongyuth, P.; Ghosh, P. K.; Gupta, P. C.; Patwardhan, A. K.; Prakash, Satya

    1993-06-01

    Blocks of 'all weld' metal were prepared by a multipass submerged arc process, using a C-Mn filler wire, at different welding currents and speeds by keeping the arc voltage constant. The variation in welding parameters was found to alter the macrostructure primarily by influencing its co-axial dendrite content. The chemical composition and hardness of the dendritic and the heat affected regions were affected little by the welding parameters. A dendrite content up to 37%, had no significant effect on the tensile properties. However an increase in it beyond 37% was found to enhance the UTS and YS and reduce percent elongation. The tensile strength was found to be a maximum in the L orientation and a minimum in the S direction. The use of post-weld heat treatment (PWHT) at 873 K caused spheroidization of cementite there by somewhat reducing the hardness and strength. The treatment while not affecting the basic dendritic morphology reduced the observed difference in tensile properties along the L, T and S directions. Implications of the data vis-a-vis industrial applications have been discussed.

  5. Low-energy electron effects on tensile modulus and infrared transmission properties of a polypyromellitimide film

    NASA Technical Reports Server (NTRS)

    Ferl, J. E.; Long, E. R., Jr.

    1981-01-01

    Infrared (IR) spectroscopy and tensile modulus testing were used to evaluate the importance of experimental procedure on changes in properties of pyromellitic dianhydride-p,p prime-oxydianiline film exposed to electron radiation. The radiation exposures were accelerated, approximate equivalents to the total dose expected for a 30 year mission in geosynchronous Earth orbit. The change in the tensile modulus depends more on the dose rate and the time interval between exposure and testing than on total dose. The IR data vary with both total dose and dose rate. A threshold dose rate exists below which reversible radiation effects on the IR spectra occur. Above the threshold dose rate, irreversible effects occur with the appearance of a new band. Post-irradiation and in situ IR absorption bands are significantly different. It is suggested that the electron radiation induced metastable, excites molecular states.

  6. Tensile properties of 21-6-9 stainless steel at elevated temperatures

    SciTech Connect

    Torres, S.G.; Henshall, G.A.

    1993-10-01

    Tensile properties of Type 21-6-9 austenitic stainless steel were measured at temperatures ranging from ambient to 1200C at a strain rate of 6.67 {times} 10{sup {minus}4} s{sup {minus}1}. Data show that yield stress decreases rapidly from room temperature to about 300C, followed by a nearly constant value in the `plateau` region from 300 to 600C. Beyond the ``plateau,`` there is more rapid drop in yield stress as temperature increases. Ultimate tensile stress shows a plateau between 300 and 700 C, which may be caused by solutes. 21-6-9 stainless steel has excellent ductility, with the elongation to failure ranging from 55 to 95%. It appears that there is a local minimum in the ductility at approximately 700C. Results are compared with earlier results of Kassner and co-workers.

  7. Relationship of microstructure and tensile properties for neutron-irradiated vanadium alloys

    SciTech Connect

    Loomis, B.A.; Smith, D.L.

    1990-01-01

    The microstructures in V-15Cr-5Ti, V-10Cr-5RTi, V-3Ti-1Si, V-15Ti-7.5Cr, and V-20Ti alloys were examined by transmission electron microscopy after neutron irradiation at 600{degree}C to 21--84 atom displacements per atom in the Materials Open Test Assembly of the Fast Flux Test Facility. The microstructures in these irradiated alloys were analyzed to determine the radiation-produced dislocation density, precipitate number density and size, and void number density and size. The results of these analyses were used to compute increases in yield stress and swelling of the irradiated alloys. The computed increase in yield stress was compared with the increase in yield stress determined from tensile tests on these irradiated alloys. This comparison made it possible to evaluate the influence of alloy composition on the evolution of radiation-damaged microstructures and the resulting tensile properties. 11 refs.

  8. Effects of Long-Term Thermal Exposure on Commercially Pure Titanium Grade 2 Elevated-Temperature Tensile Properties

    NASA Technical Reports Server (NTRS)

    Ellis, David L.

    2012-01-01

    Elevated-temperature tensile testing of commercially pure titanium (CP Ti) Grade 2 was conducted for as-received commercially produced sheet and following thermal exposure at 550 and 650 K (531 and 711 F) for times up to 5000 h. The tensile testing revealed some statistical differences between the 11 thermal treatments, but most thermal treatments were statistically equivalent. Previous data from room temperature tensile testing was combined with the new data to allow regression and development of mathematical models relating tensile properties to temperature and thermal exposure. The results indicate that thermal exposure temperature has a very small effect, whereas the thermal exposure duration has no statistically significant effects on the tensile properties. These results indicate that CP Ti Grade 2 will be thermally stable and suitable for long-duration space missions.

  9. Coating of carbon nanotube fibers: variation of tensile properties, failure behavior and adhesion strength

    NASA Astrophysics Data System (ADS)

    Mäder, Edith; Liu, Jian-Wen; Hiller, Janett; Lu, Weibang; Li, Qingwen; Zhandarov, Serge; Chou, Tsu-Wei

    2015-07-01

    An experimental study of the tensile properties of CNT fibers and their interphasial behavior in epoxy matrices is reported. One of the most promising applications of CNT fibers is their use as reinforcement in multifunctional composites. For this purpose, an increase of the tensile strength of the CNT fibers in unidirectional composites as well as strong interfacial adhesion strength is desirable. However, the mechanical performance of the CNT fiber composites manufactured so far is comparable to that of commercial fiber composites. The interfacial properties of CNT fiber/polymer composites have rarely been investigated and provided CNT fiber/epoxy interfacial shear strength of 14.4 MPa studied by the microbond test. In order to improve the mechanical performance of the CNT fibers, an epoxy compatible coating with nano-dispersed aqueous based polymeric film formers and low viscous epoxy resin, respectively, was applied. For impregnation of high homogeneity, low molecular weight epoxy film formers and polyurethane film formers were used. The aqueous based epoxy film formers were not crosslinked and able to interdiffuse with the matrix resin after impregnation. Due to good wetting of the individual CNT fibers by the film formers, the degree of activation of the fibers was improved leading to increased tensile strength and Young’s modulus. Cyclic tensile loading and simultaneous determination of electric resistance enabled to characterize the fiber’s durability in terms of elastic recovery and hysteresis. The pull-out tests and SEM study reveal different interfacial failure mechanisms in CNT fiber/epoxy systems for untreated and film former treated fibers, on the one hand, and epoxy resin treated ones, on the other hand. The epoxy resin penetrated between the CNT bundles in the reference or film former coated fiber, forming a relatively thick CNT/epoxy composite layer and thus shifting the fracture zone within the fiber. In contrast to this, shear sliding along

  10. Tensile Properties and Small-Angle Neutron Scattering Investigation of Stereoblock Elastomeric Polypropylene

    SciTech Connect

    Pople, John A

    2002-08-06

    Elastomeric polypropylene (ePP) produced from unbridged 2-arylindene metallocene catalysts was studied by uniaxial tensile and small-angle neutron scattering (SANS) techniques. The ePP can be separated into three fractions by successive boiling-solvent fractionation method to yield: a low-tacticity fraction soluble in ether (ES), an intermediate-tacticity fraction soluble in heptane (HS), and a high-tacticity fraction insoluble in heptane (HI). Tensile properties of ePP were compared to its solvent fractions, and the role of each solvent fraction residing within ePP was investigated by blending 5 weight % deuterated fraction with ePP. The tensile properties of each fraction vary considerably, exhibiting properties from a weak gum elastomer for ES, to a semi-crystalline thermoplastic for HI. The intermediate-tacticity HS fraction exhibits elastic properties similar to the parent elastomer (ePP). In the melt at 160 C, SANS shows that all deuterated fractions are homogeneously mixed with ePP in a one-phase system. At 25 C upon a slow cooling from the melt, the low-tacticity fraction is preferentially segregated in the amorphous domains induced by different crystallization temperatures and kinetics of the deuterated ES and high-tacticity components. The high-tacticity component within ePP (dHI-ePP) retains its plastic properties in the blend. Despite its low crystallinity ({le} 2%), the low-tacticity fraction can co-crystallize with the crystalline matrix. The dES-ePP shows little or no relaxation when held under strain and recovers readily upon the release of stress.

  11. Tensile properties of the medial patellofemoral ligament: The effect of specimen orientation

    PubMed Central

    Kim, Kwang E.; Hsu, Shan-Ling; Woo, Savio L-Y.

    2014-01-01

    For recurrent patellar dislocation, reconstruction of the medial patellofemoral ligament (MPFL) with replacement autografts has often been performed but with only little data on the tensile properties of the MPFL to guide graft selection. With its complex anatomy and geometry, these properties are difficult to obtain. In this study, we showed how the orientation of the femur-MPFL-patella complex (FMPC) during uniaxial tensile testing can have a significant effect on its structural properties. Twenty two FMPCs were isolated from porcine stifle joints and randomly assigned to two groups of 11 each. For the first group, the specimens were loaded to failure with the patella oriented 30 degrees away from the direction of the applied load to mimic its orientation in situ, called natural orientation. In the second group, the patella was aligned in the direction of the tensile load, called non-natural orientation. The stiffness for the natural orientation group was 65 ± 13 N/mm, 32% higher than that for the non-natural orientation group (50 ± 17 N/mm; p < 0.05). The ultimate loads were 438 ± 128 N and 386 ± 136 N, respectively (p > 0.05). Ten out of 11 specimens in the natural orientation group failed at the femoral attachment (the narrowest portion of the MPFL) compared to 6 out of 11 in the non-natural orientation group. Our findings suggest that the specimen orientation that mimics the in-situ loading conditions of the MPFL should be used to obtain more representative data for the structural properties of the FMPC. PMID:24332616

  12. Effects of H content on the tensile properties and fracture behavior of SA508-III steel

    NASA Astrophysics Data System (ADS)

    Liu, Jia-hua; Wang, Lei; Liu, Yang; Song, Xiu; Luo, Jiong; Yuan, Dan

    2015-08-01

    SA508-III steel was charged with different hydrogen (H) contents using a high-pressure thermal charging method to study the effects of H content on the tensile properties and evaluate the H embrittlement behavior of the steel. The results indicate that the ultimate tensile strength remains nearly unchanged with the addition of H. In contrast, the yielding strength slightly increases, and the elongation significantly decreases with increasing H content, especially at concentrations exceeding 5.6 × 10-6. On the basis of fractographic analysis, it is clear that the addition of H changes the fracture mode from microvoid coalescence to a mixture of river patterns and dimples. Carbides are strong traps for H; thus, the H atoms easily migrate in the form of Cottrell atmosphere toward the carbides following moving dislocations during tensile deformation. In addition, stress-induced H atoms accumulate at the interface between carbides and the matrix after necking under three-dimensional stress, which weakens the interfacial bonding force. Consequently, when the local H concentration reaches a critical value, microcracks occur at the interface, resulting in fracture.

  13. 42 CFR 35.65 - Acceptable personal property.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Acceptable personal property. 35.65 Section 35.65 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICAL CARE AND EXAMINATIONS HOSPITAL AND STATION MANAGEMENT Contributions for the Benefit of Patients § 35.65...

  14. 42 CFR 35.65 - Acceptable personal property.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Acceptable personal property. 35.65 Section 35.65 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICAL CARE AND EXAMINATIONS HOSPITAL AND STATION MANAGEMENT Contributions for the Benefit of Patients § 35.65...

  15. 42 CFR 35.65 - Acceptable personal property.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Acceptable personal property. 35.65 Section 35.65 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICAL CARE AND EXAMINATIONS HOSPITAL AND STATION MANAGEMENT Contributions for the Benefit of Patients § 35.65...

  16. Nonlinear and Anisotropic Tensile Properties of Graft Materials used in Soft Tissue Applications

    PubMed Central

    Yoder, Jonathon H; Elliott, Dawn M

    2010-01-01

    Background The mechanical properties of extracellular matrix grafts that are intended to augment or replace soft tissues should be comparable to the native tissue. Such grafts are often used in fiber-reinforced tissue applications that undergo multi-axial loading and therefore knowledge of the anisotropic and nonlinear properties are needed, including the moduli and Poisson's ratio in two orthogonal directions within the plane of the graft. The objective of this study was to measure the tensile mechanical properties of several marketed grafts: Alloderm, Restore, CuffPatch, and OrthADAPT. Methods The degree of anisotropy and nonlinearity within each graft was evaluated from uniaxial tensile tests and compared to their native tissue. Results The Alloderm graft was anisotropic in both the toe and linear-region of the stress-strain response, was highly nonlinear, and generally had low properties. The Restore and CuffPatch grafts had similar stress-strain responses, were largely isotropic, had a linear-region modulus of 18 MPa, and were nonlinear. OrthADAPT was anisotropic in the linear region (131 vs 47 MPa) and was highly nonlinear. The Poisson ratio for all grafts was between 0.4 and 0.7, except for the parallel orientation of Restore which was greater than 1.0. Interpretation Having an informed understanding of how the available grafts perform mechanically will allow for better assessment by the physician for which graft to apply depending upon its application. PMID:20129728

  17. Tensile properties of a boron/nitrogen-doped carbon nanotube–graphene hybrid structure

    PubMed Central

    Xia, Kang; Zhan, Haifei; Wei, Ye

    2014-01-01

    Summary Doping is an effective approach that allows for the intrinsic modification of the electrical and chemical properties of nanomaterials. Recently, a graphene and carbon nanotube hybrid structure (GNHS) has been reported, which extends the excellent properties of carbon-based materials to three dimensions. In this paper, we carried out a first-time investigation on the tensile properties of the hybrid structures with different dopants. It is found that with the presence of dopants, the hybrid structures usually exhibit lower yield strength, Young’s modulus, and earlier yielding compared to that of a pristine hybrid structure. For dopant concentrations below 2.5% no significant reduction of Young’s modulus or yield strength could be observed. For all considered samples, the failure is found to initiate at the region where the nanotubes and graphene sheets are connected. After failure, monatomic chains are normally observed around the failure region. Dangling graphene layers without the separation of a residual CNT wall are found to adhere to each other after failure with a distance of about 3.4 Å. This study provides a fundamental understanding of the tensile properties of the doped graphene–nanotube hybrid structures, which will benefit the design and also the applications of graphene-based hybrid materials. PMID:24778956

  18. Self-Healing Nanofiber-Reinforced Polymer Composites. 1. Tensile Testing and Recovery of Mechanical Properties.

    PubMed

    Lee, Min Wook; An, Seongpil; Jo, Hong Seok; Yoon, Sam S; Yarin, Alexander L

    2015-09-01

    The present work aims at development of self-healing materials capable of partially restoring their mechanical properties under the conditions of prolonged periodic loading and unloading, which is characteristic, for example, of aerospace applications. Composite materials used in these and many other applications frequently reveal multiple defects stemming from their original inhomogeneity, which facilitates microcracking and delamination at ply interfaces. Self-healing nanofiber mats may effectively prevent such damage without compromising material integrity. Two types of core-shell nanofibers were simultaneously electrospun onto the same substrate in order to form a mutually entangled mat. The first type of core-shell fibers consisted of resin monomer (dimethylsiloxane) within the core and polyacrylonitrile within the shell. The second type of core-shell nanofibers consisted of cure (dimethyl-methyl hydrogen-siloxane) within the core and polyacrylonitrile within the shell. These mutually entangled nanofiber mats were used for tensile testing, and they were also encased in polydimethylsiloxane to form composites that were also subsequently subjected to tensile testing. During tensile tests, the nanofibers can be damaged in stretching up to the plastic regime of deformation. Then, the resin monomer and cure was released from the cores and the polydimethylsiloxane resin was polymerized, which might be expected to result in the self-healing properties of these materials. To reveal and evaluate the self-healing properties of the polyacrylonitrile-resin-cure nanofiber mats and their composites, the results were compared to the tensile test results of the monolithic polyacrylonitrile nanofiber mats or composites formed by encasing polyacrylonitrile nanofibers in a polydimethylsiloxane matrix. The latter do not possess self-healing properties, and indeed, do not recover their mechanical characteristics, in contrast to the polyacrylonitrile-resin-cure nanofiber mats and

  19. Transverse-Weld Tensile Properties of a New Al-4Cu-2Si Alloy as Filler Metal

    NASA Astrophysics Data System (ADS)

    Sampath, K.

    2009-12-01

    AA2195, an Al-Cu-Li alloy in the T8P4 age-hardened condition, is a candidate aluminum armor for future combat vehicles, as this material offers higher static strength and ballistic protection than current aluminum armor alloys. However, certification of AA2195 alloy for armor applications requires initial qualification based on the ballistic performance of welded panels in the as-welded condition. Currently, combat vehicle manufacturers primarily use gas metal arc welding (GMAW) process to meet their fabrication needs. Unfortunately, a matching GMAW consumable electrode is currently not commercially available to allow effective joining of AA2195 alloy. This initial effort focused on an innovative, low-cost, low-risk approach to identify an alloy composition suitable for effective joining of AA2195 alloy, and evaluated transverse-weld tensile properties of groove butt joints produced using the identified alloy. Selected commercial off-the-shelf (COTS) aluminum alloy filler wires were twisted to form candidate twisted filler rods. Representative test weldments were produced using AA2195 alloy, candidate twisted filler rods and gas tungsten arc welding (GTAW) process. Selected GTA weldments produced using Al-4wt.%Cu-2wt.%Si alloy as filler metal consistently provided transverse-weld tensile properties in excess of 275 MPa (40 ksi) UTS and 8% El (over 25 mm gage length), thereby showing potential for acceptable ballistic performance of as-welded panels. Further developmental work is required to evaluate in detail GMAW consumable wire electrodes based on the Al-Cu-Si system containing 4.2-5.0 wt.% Cu and 1.6-2.0 wt.% Si.

  20. A novel in situ device based on a bionic piezoelectric actuator to study tensile and fatigue properties of bulk materials

    NASA Astrophysics Data System (ADS)

    Wang, Shupeng; Zhang, Zhihui; Ren, Luquan; Zhao, Hongwei; Liang, Yunhong; Zhu, Bing

    2014-06-01

    In this work, a miniaturized device based on a bionic piezoelectric actuator was developed to investigate the static tensile and dynamic fatigue properties of bulk materials. The device mainly consists of a bionic stepping piezoelectric actuator based on wedge block clamping, a pair of grippers, and a set of precise signal test system. Tensile and fatigue examinations share a set of driving system and a set of signal test system. In situ tensile and fatigue examinations under scanning electron microscope or metallographic microscope could be carried out due to the miniaturized dimensions of the device. The structure and working principle of the device were discussed and the effects of output difference between two piezoelectric stacks on the device were theoretically analyzed. The tensile and fatigue examinations on ordinary copper were carried out using this device and its feasibility was verified through the comparison tests with a commercial tensile examination instrument.

  1. A novel in situ device based on a bionic piezoelectric actuator to study tensile and fatigue properties of bulk materials.

    PubMed

    Wang, Shupeng; Zhang, Zhihui; Ren, Luquan; Zhao, Hongwei; Liang, Yunhong; Zhu, Bing

    2014-06-01

    In this work, a miniaturized device based on a bionic piezoelectric actuator was developed to investigate the static tensile and dynamic fatigue properties of bulk materials. The device mainly consists of a bionic stepping piezoelectric actuator based on wedge block clamping, a pair of grippers, and a set of precise signal test system. Tensile and fatigue examinations share a set of driving system and a set of signal test system. In situ tensile and fatigue examinations under scanning electron microscope or metallographic microscope could be carried out due to the miniaturized dimensions of the device. The structure and working principle of the device were discussed and the effects of output difference between two piezoelectric stacks on the device were theoretically analyzed. The tensile and fatigue examinations on ordinary copper were carried out using this device and its feasibility was verified through the comparison tests with a commercial tensile examination instrument. PMID:24985848

  2. A novel in situ device based on a bionic piezoelectric actuator to study tensile and fatigue properties of bulk materials

    SciTech Connect

    Wang, Shupeng; Zhang, Zhihui Ren, Luquan; Liang, Yunhong; Zhao, Hongwei; Zhu, Bing

    2014-06-15

    In this work, a miniaturized device based on a bionic piezoelectric actuator was developed to investigate the static tensile and dynamic fatigue properties of bulk materials. The device mainly consists of a bionic stepping piezoelectric actuator based on wedge block clamping, a pair of grippers, and a set of precise signal test system. Tensile and fatigue examinations share a set of driving system and a set of signal test system. In situ tensile and fatigue examinations under scanning electron microscope or metallographic microscope could be carried out due to the miniaturized dimensions of the device. The structure and working principle of the device were discussed and the effects of output difference between two piezoelectric stacks on the device were theoretically analyzed. The tensile and fatigue examinations on ordinary copper were carried out using this device and its feasibility was verified through the comparison tests with a commercial tensile examination instrument.

  3. Influences of post-weld heat treatment on tensile properties of friction stir-welded AA6061 aluminum alloy joints

    SciTech Connect

    Elangovan, K.; Balasubramanian, V.

    2008-09-15

    This paper reports on studies of the influences of various post-weld heat treatment procedures on tensile properties of friction stir-welded AA6061 aluminum alloy joints. Rolled plates of 6-mm thick AA6061 aluminum alloy were used to fabricate the joints. Solution treatment, an artificial aging treatment and a combination of both were given to the welded joints. Tensile properties such as yield strength, tensile strength, elongation and joint efficiency were evaluated. Microstructures of the welded joints were analyzed using optical microscopy and transmission electron microscopy. A simple artificial aging treatment was found to be more beneficial than other treatment methods to enhance the tensile properties of the friction stir-welded AA6061 aluminum alloy joints.

  4. The influence of composition gradients on tensile properties of weld metal

    SciTech Connect

    Choi, I.D.; Matlock, D.K.; Olson, D.L.

    1988-09-01

    In this study, the effects of weld metal microsegregation, as altered by post-weld heat treatments, on both low and high temperature tensile properties were investigated on an alloy system which exhibits significant segregation of the major alloying elements without complex transformations or precipitation. Monel alloy 400, which consists primarily of nickel and copper, was chosen as a model system. This system is a single phase FCC solid solution at all temperatures, and has a low distribution coefficient, k. On solidification, significant microsegregation occurs with copper segregating to the interdendritic boundaries.

  5. The influence of yarn treatment on the tensile properties of biocomposites

    NASA Astrophysics Data System (ADS)

    Širvaitienė, Anne; Jankauskaitė, Virginija; Bekampienė, Paulė; Sankauskaitė, Audronė

    2012-07-01

    The aim of this work was to investigate the influence of cotton and linen yarns treatments at different hierarchical levels on the biocomposite tensile properties. The biodegradable poly(lactic acid) (PLA) resin was used as the matrix polymer. The water based mercerization and low pressure plasma treatment were applied for chemical modification of yarns macro- and microfibrils. To improve fiber orientation of fibre bundles and single fibers the pretension of yarn was used. It was obtained that the most efficient is the complex yarns treatment, plasma treatment with subsequent pre-tension, where especially notable was the positive effect of low-pressure plasma.

  6. Tensile properties and deformation mechanisms of a 14Cr ODS ferritic steel

    NASA Astrophysics Data System (ADS)

    Steckmeyer, A.; Praud, M.; Fournier, B.; Malaplate, J.; Garnier, J.; Béchade, J. L.; Tournié, I.; Tancray, A.; Bougault, A.; Bonnaillie, P.

    2010-10-01

    The search for a new cladding material is part of the research studies carried out at CEA to develop a sodium-cooled fast reactor meeting the expectations of the Generation IV International Forum. In this study, the tensile properties of a ferritic oxide dispersion strengthened steel produced by hot extrusion at CEA have been evaluated. They prove the studied alloy to be as resistant as and more ductile than the other nano-reinforced alloys of literature. The effects of the strain rate and temperature on the total plastic strain of the material remind of diffusion phenomena. Intergranular damage and intergranular decohesion are clearly highlighted.

  7. Tensile properties of aluminized V-5Cr-5Ti alloy after exposure in air environment

    SciTech Connect

    Natesan, K.; Soppet, W.K.

    1997-08-01

    The objectives of this task are to (a) develop procedures to modify surface regions of V-Cr-Ti alloys in order to minimize oxygen uptake by the alloys when exposed to environments that contain oxygen, (b) evaluate the oxygen uptake of the surface-modified V-Cr-Ti alloys as a function of temperature an oxygen partial pressure in the exposure environment, (c) characterize the microstructures of oxide scales and oxygen trapped at the grain boundaries of the substrate alloys, and (d) evaluate the influence of oxygen uptake on the tensile properties of the modified alloys at room and elevated temperatures.

  8. Tensile properties of V-Cr-Ti alloys after exposure in hydrogen-containing environments

    SciTech Connect

    Natesan, K.; Soppet, W.K.

    1998-09-01

    A systematic study has been initiated at Argonne National Laboratory to evaluate the performance of several V-Cr-Ti alloys after exposure to environments containing hydrogen at various partial pressures. The goal is to correlate the chemistry of the exposure environment with hydrogen uptake in the samples and its influence on the microstructure and tensile properties of the alloys. At present, the principal effort has focused on the V-4Cr-4Ti alloy of heat identified as BL-71; however other alloys (V-5Cr-5Ti alloy of heats BL-63, and T87, plus V-4Cr-4Ti alloy from General Atomics [GA]) are also being evaluated. Other variables of interest are the effect of initial grain size on the tensile behavior of the alloys. Experiments conducted on specimens of various V-Cr-Ti alloys exposed to pH{sub 2} levels of 0.01 and 3 {times} 10{sup {minus}6} torr showed negligible effect of H{sub 2} on either maximum engineering stress or uniform and total elongation. However, uniform and total elongation decreased substantially when the alloys were exposed to 1.0 torr H{sub 2} pressure. Preliminary data from sequential exposures of the materials to low-pO{sub 2} and several low-pH{sub 2} environments did not reveal an adverse effect on the maximum engineering stress or on uniform and total elongation. Further, tests in H{sub 2} environments on specimens annealed at different temperatures showed that grain-size variation by a factor of {approx}2 had little or no effect on tensile properties.

  9. Relationship between the ideal tensile strength and the friction properties of metals in contact with nonmetals and themselves

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Buckley, D. H.

    1981-01-01

    The adhesion and friction properties of metals in contact with diamond, boron nitride, silicon carbide, manganese-zinc ferrite, and the metals themselves in vacuum was investigated. An estimate of the ideal uniaxial tensile was obtained in terms of the equilibrium surface energy, interplanar spacing of the planes perpendicular to the tensile axis, and the Young's modulus of elasticity. The coefficient of friction for metals was found to be related to the ideal tensile strength of metals. The higher the strength of the metal, the lower the coefficient of friction.

  10. A new tensile stage for in situ electron microscopy examination of the mechanical properties of 'superelastic' specimens

    SciTech Connect

    Dragnevski, Kalin I.; Fairhead, Trevor W.; Balsod, Rik; Donald, Athene M.

    2008-12-15

    We have developed a novel tensile stage that can be used for in situ electron microscopy examination of the mechanical properties of ''superelastic'' materials. In our stage, one of the specimen clamps is replaced by a cylindrical roller, which when driven by a motor can easily stretch (''roll on'') any specimen irrespective of its plastic properties. We have used the so-called Roll-o-meter in the study of the tensile behavior of two different film formed latex formulations, here referred to as standard and novel. We find that the values of the tensile strength and extension to break of the studied systems, measured by using the Roll-o-meter, are similar to those measured by a Hounsfield tensile testing machine outside the microscope chamber. Further, in situ environmental scanning electron microscopy examination of the deformation and failure of the lattices revealed that the standard specimens exhibit a more ductile behavior, compared to the novel ones.

  11. Preparation and tensile properties of linear low density polyethylene/rambutan peels (Nephelium chryseum Blum.) flour blends

    NASA Astrophysics Data System (ADS)

    Nadhirah, A. Ainatun.; Sam, S. T.; Noriman, N. Z.; Voon, C. H.; Samera, S. S.

    2015-05-01

    The effect of rambutan peels flour (RPF) content on the tensile properties of linear low density polyethylene filled with rambutan peel flour was studied. RPF was melt blended with linear low-density polyethylene (LLDPE). LLDPE/RPF blends were prepared by using internal mixer (brabender) at 160 °C with the flour content ranged from 0 to 15 wt%. The tensile properties were tested by using a universal testing machine (UTM) according to ASTM D638. The highest tensile strength was observed for pure LLDPE while the tensile strength LLDPE/RPF decreased gradually with the addition of rambutan peels flour content from 0% to 15%. Young's modulus of 63 µm to 250 µm rambutan peels blends with LLDPE with the fiber loading of 0 - 15 wt% increased with increasing fiber loading.

  12. Microstructure and Mechanical Tensile Properties of a VT6 Alloy Manufactured by Selective Laser Melting

    NASA Astrophysics Data System (ADS)

    Nazarova, T. I.; Imayev, V. M.; Imayev, R. M.; Pavlinich, S. P.

    2015-10-01

    The microstructure and tensile properties of a material manufactured from the VT6 titanium alloy by the method of selective laser melting (SLM) are investigated. In the initial state, the microstructure of the SLMmaterial consists of columnar β-grains elongated in the direction of heat sink, which were transformed during cooling into the acicular martensite α'-phase. A heat treatment, including two-stage annealing at 900 and 700°C, transfers the microstructure into equilibrium, two-phase state, with the elongation of β-grains being retained. Mechanical tensile tests were performed in the direction normal to the layer packing formed during SLM. It is found that strength properties of the workpiece manufactured by the SLM process are similar to those of the VT6 alloy manufactured by conventional casting, while its room-temperature ductility is noticeably higher. Deformation-relief studies of the specimen surface demonstrated that the layers formed during SLM affect neither the development of deformation nor fracture of the material.

  13. Novel strip-cast Mg/Al clad sheets with excellent tensile and interfacial bonding properties

    NASA Astrophysics Data System (ADS)

    Kim, Jung-Su; Lee, Dong Ho; Jung, Seung-Pill; Lee, Kwang Seok; Kim, Ki Jong; Kim, Hyoung Seop; Lee, Byeong-Joo; Chang, Young Won; Yuh, Junhan; Lee, Sunghak

    2016-06-01

    In order to broaden industrial applications of Mg alloys, as lightest-weight metal alloys in practical uses, many efforts have been dedicated to manufacture various clad sheets which can complement inherent shortcomings of Mg alloys. Here, we present a new fabrication method of Mg/Al clad sheets by bonding thin Al alloy sheet on to Mg alloy melt during strip casting. In the as-strip-cast Mg/Al clad sheet, homogeneously distributed equi-axed dendrites existed in the Mg alloy side, and two types of thin reaction layers, i.e., γ (Mg17Al12) and β (Mg2Al3) phases, were formed along the Mg/Al interface. After post-treatments (homogenization, warm rolling, and annealing), the interfacial layers were deformed in a sawtooth shape by forming deformation bands in the Mg alloy and interfacial layers, which favorably led to dramatic improvement in tensile and interfacial bonding properties. This work presents new applications to multi-functional lightweight alloy sheets requiring excellent formability, surface quality, and corrosion resistance as well as tensile and interfacial bonding properties.

  14. Structural and High-Temperature Tensile Properties of Special Pitch-Coke Graphites

    NASA Technical Reports Server (NTRS)

    Kotlensky, W. V.; Martens, H. E.

    1961-01-01

    The room-temperature structural properties and the tensile properties up to 5000 F (275O C) were determined for ten grades of specially prepared petroleum-coke coal-tar-pitch graphites which were graphitized at 5430 F (3000 C). One impregnation with coal-tar pitch increased the bulk density from 1.41 to 1.57 g/cm3 and the maximum strength at 4500 F (2500 C) from 4000 to 5700 psi. None of the processing parameters studied had a marked effect on the closed porosity or the X-ray structure or the per cent graphitization. The coarse-particle filler resulted in the lowest coefficient of thermal expansion and the fine-particle filler in the highest coefficient. A marked improvement in uniformity of tensile strength was observed. A standard-deviation analysis gave a one-sigma value of approximately 150 psi for one of these special grades and values of 340-420 psi for three commercial grades.

  15. Novel strip-cast Mg/Al clad sheets with excellent tensile and interfacial bonding properties

    PubMed Central

    Kim, Jung-Su; Lee, Dong Ho; Jung, Seung-Pill; Lee, Kwang Seok; Kim, Ki Jong; Kim, Hyoung Seop; Lee, Byeong-Joo; Chang, Young Won; Yuh, Junhan; Lee, Sunghak

    2016-01-01

    In order to broaden industrial applications of Mg alloys, as lightest-weight metal alloys in practical uses, many efforts have been dedicated to manufacture various clad sheets which can complement inherent shortcomings of Mg alloys. Here, we present a new fabrication method of Mg/Al clad sheets by bonding thin Al alloy sheet on to Mg alloy melt during strip casting. In the as-strip-cast Mg/Al clad sheet, homogeneously distributed equi-axed dendrites existed in the Mg alloy side, and two types of thin reaction layers, i.e., γ (Mg17Al12) and β (Mg2Al3) phases, were formed along the Mg/Al interface. After post-treatments (homogenization, warm rolling, and annealing), the interfacial layers were deformed in a sawtooth shape by forming deformation bands in the Mg alloy and interfacial layers, which favorably led to dramatic improvement in tensile and interfacial bonding properties. This work presents new applications to multi-functional lightweight alloy sheets requiring excellent formability, surface quality, and corrosion resistance as well as tensile and interfacial bonding properties. PMID:27245687

  16. Novel strip-cast Mg/Al clad sheets with excellent tensile and interfacial bonding properties.

    PubMed

    Kim, Jung-Su; Lee, Dong Ho; Jung, Seung-Pill; Lee, Kwang Seok; Kim, Ki Jong; Kim, Hyoung Seop; Lee, Byeong-Joo; Chang, Young Won; Yuh, Junhan; Lee, Sunghak

    2016-01-01

    In order to broaden industrial applications of Mg alloys, as lightest-weight metal alloys in practical uses, many efforts have been dedicated to manufacture various clad sheets which can complement inherent shortcomings of Mg alloys. Here, we present a new fabrication method of Mg/Al clad sheets by bonding thin Al alloy sheet on to Mg alloy melt during strip casting. In the as-strip-cast Mg/Al clad sheet, homogeneously distributed equi-axed dendrites existed in the Mg alloy side, and two types of thin reaction layers, i.e., γ (Mg17Al12) and β (Mg2Al3) phases, were formed along the Mg/Al interface. After post-treatments (homogenization, warm rolling, and annealing), the interfacial layers were deformed in a sawtooth shape by forming deformation bands in the Mg alloy and interfacial layers, which favorably led to dramatic improvement in tensile and interfacial bonding properties. This work presents new applications to multi-functional lightweight alloy sheets requiring excellent formability, surface quality, and corrosion resistance as well as tensile and interfacial bonding properties. PMID:27245687

  17. Change in tensile properties of neoprene and nitrile gloves after repeated exposures to acetone and thermal decontamination.

    PubMed

    Gao, Pengfei; Tomasovic, Beth

    2005-11-01

    This study investigated the change in tensile properties of neoprene and nitrile gloves after repeated cycles of exposure to acetone, followed by thermal decontamination. The glove was exposed to acetone (outer surface in contact with chemical), subjected to thermal decontamination, and tested for the tensile strength and the ultimate elongation. Thermal decontamination was carried out inside an oven for 16 hours at 100 degrees C. The exposure/decontamination procedure was repeated for a maximum of 10 cycles. For neoprene versus acetone, the mean tensile strength consistently decreased after each exposure/decontamination cycle. Multiple comparisons indicated that the mean tensile strengths between the new swatches and each exposure/decontamination group were significantly different (p < 0.05). The loss of either tensile strength or ultimate elongation was less than 23% compared with new swatches after four exposure/decontamination cycles. Swatches with out acetone exposure were then cycled through the oven in the same manner. It was found that both the heat used for thermal decontamination and acetone exposure significantly affected the tensile strength and ultimate elongation. For nitrile gloves exposed to acetone, the mean tensile strength remained virtually unchanged (p > 0.05). The mean tensile strength for the new swatches was 37.1 MPa and the mean tensile strength after nine exposure/decontamination cycles was 36.0 MPa, with a loss less than 3%. The largest single cycle loss for ultimate elongation occurred during the first exposure/decontamination cycle for both glove materials. In our previous study, decisions regarding the effectiveness of the decontamination process were based on having no discernible change in the breakthrough time and steady-state permeation rate. The results of this study indicate that the effectiveness of the decontamination process cannot be based on permeation parameters alone but must also take into account the change in physical

  18. High Temperature Tensile Properties of Unidirectional Hi-Nicalon/Celsian Composites In Air

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, John Z.; Bansal, Narottam P.

    2000-01-01

    High temperature tensile properties of unidirectional BN/SiC-coated Hi-Nicalon SiC fiber reinforced celsian matrix composites have been measured from room temperature to 1200 C (2190 F) in air. Young's modulus, the first matrix cracking stress, and the ultimate strength decreased from room temperature to 1200 C (2190 F). The applicability of various micromechanical models, in predicting room temperature values of various mechanical properties for this CMC, has also been investigated. The simple rule of mixtures produced an accurate estimate of the primary composite modulus. The first matrix cracking stress estimated from ACK theory was in good agreement with the experimental value. The modified fiber bundle failure theory of Evans gave a good estimate of the ultimate strength.

  19. Comparison of Elevated Temperature Tensile Properties and Fatigue Behavior of Two Variants of a Woven SiC/SiC Composite

    NASA Technical Reports Server (NTRS)

    Kalluri, Sreeramesh; Brewer, David N.; Sreeramesh, Kalluri

    2005-01-01

    Tensile properties (elastic modulus, proportional limit strength, in-plane tensile strength, and strain at failure) of two variants of a woven SiC/SiC composite, manufactured during two separate time periods (9/99 and 1/01), were determined at 1038 and 1204 C by conducting tensile tests on specimens machined from plates. Continuous cycling fatigue tests (R = 0.05) and 20 cpm) were also conducted at the same two temperatures on specimens from both composites. In this study, average tensile properties, 95% confidence intervals associated with the tensile properties, and geometric mean fatigue lives of both composite materials are compared. The observed similarities and differences in the tensile properties are highlighted and an attempt is made to understand the relationship, if any, between the tensile properties and the fatigue behaviors of the two woven composites.

  20. Effects of degeneration on the compressive and tensile properties of human meniscus.

    PubMed

    Fischenich, Kristine M; Lewis, Jackson; Kindsfater, Kirk A; Bailey, Travis S; Haut Donahue, Tammy L

    2015-06-01

    Healthy menisci function within the joint to prevent the underlying articular cartilage from excessive loads. Understanding how mechanical properties of menisci change with degeneration can drive future therapeutic studies to prevent this degeneration. Thus, the goal of this study was to characterize both compressive and tensile moduli of human menisci with varying degrees of gross damage due to osteoarthritis (OA). Twenty four paired menisci were collected from total knee joint replacement patients and the menisci were graded on a scale from 0-4 according to level of gross meniscal degeneration with 0=normal and 4=full tissue maceration. Each meniscus was then sectioned into anterior and posterior regions and subjected to indentation relaxation tests. Samples were sliced into 1mm thick strips, made into dumbbells using a custom punch, and pulled to failure. Significant decreases in instantaneous compressive modulus were seen in the lateral posterior region between grades 0 and 1 (36% decrease) and in the medial anterior regions between grades 1 and 2 (67% decrease) and 1 and 3 (72% decrease). Changes in equilibrium modulus where seen in the lateral anterior region between grades 1 and 2 (35% decrease), lateral posterior region between grades 0-2 (41% decrease), and medial anterior regions between grades 1 and 2 (59% decrease), 1 and 3 (67% decrease), 2 and 4 (54% decrease), and 3 and 4 (42% decrease). No significant changes were observed in tensile modulus across all regions and degenerative grades. The results of this study demonstrate the compressive moduli are affected even in early stages of gross degeneration, and continue to decrease with increased deterioration. However, osteoarthritic menisci retain a tensile modulus similar to that of previously reported healthy menisci. This study highlights progressive changes in meniscal mechanical compressive integrity as level of gross tissue degradation increases, and thus, early interventions should focus on

  1. The elevated temperature tensile properties of S-200E commercially pure beryllium

    SciTech Connect

    Henshall, G.A.; Torres, S.G.; Hanafee, J.E.

    1995-09-01

    The tensile properties of commercially pure beryllium are sensitive to temperature, impurity content, texture, grain size, and prior processing. Therefore, tensile tests have been conducted using the commercially pure S-200E Be commonly employed at Lawrence Livermore National Laboratory. These experiments were performed at temperatures ranging from 300 to 1100{degrees}C in the longitudinal and transverse orientations at the quasi-static strain rate of 5.5 x 10{sup -4} s{sup -1}. The results of these experiments reveal that the stress-strain curve is smooth, ie. without yield points or serrations, over the entire temperature range studied. The yield stress (YS) and ultimate tensile stress (UTS) decrease monotonically with increasing temperature. Similar strengths were measured for both the longitudinal and transverse orientations, with the latter exhibiting slightly lower YS and UTS values. The measured failure elongation (e{sub f}) vs. temperature curve is complex due to the competing effects of increasing basal-plane fracture stress with increasing temperature combined with the presence of hot shortness at intermediate temperatures. The latter is believed to be caused, at least partially, by the presence of free aluminum impurities at the grain boundaries. This hypothesis is supported by the measured increase in e{sub f} at 700{degrees}C following a 100-hr anneal at 750{degrees}C, which would remove free Al from the grain boundaries. Texture also was found to influence e{sub f}. The favorable orientation of the basal planes for initiation and propagation of cleavage cracks in longitudinal specimens results in a significantly decreased failure elongation compared with the transverse orientation. The effects of testing temperature and specimen orientation on the reduction in area were found to be similar to those described for e{sub f}.

  2. Effect of Alloying Elements on Tensile Properties, Microstructure, and Corrosion Resistance of Reinforcing Bar Steel

    NASA Astrophysics Data System (ADS)

    Panigrahi, B. K.; Srikanth, S.; Sahoo, G.

    2009-11-01

    The effect of copper, phosphorus, and chromium present in a semikilled reinforcing bar steel produced by in-line quenching [thermomechanical treatment (TMT)] process on the tensile properties, microstructure, and corrosion resistance of steel in simulated chloride environment has been investigated. The results have been compared with that of a semikilled C-Mn reinforcing bar steel without these alloying elements produced by the same process route. Though the amount of phosphorus (0.11 wt.%) was higher than that specified by ASTM A 706 standard, the Cu-P-Cr steel exhibited a composite microstructure, and good balance of yield stress, tensile stress, elongation, and ultimate tensile to yield stress ratio. Two conventional test methods, namely, the salt fog, and potentiodynamic polarization tests, were used for the corrosion test. The rust formed on Cu-P-Cr steel was adherent, and was of multiple colors, while the corrosion products formed on the C-Mn steel were weakly adherent and relatively darker blue. Also, the free corrosion potential of the Cu-P-Cr steel was nobler, and the corrosion current was markedly lower than that of a C-Mn rebar. The Cu-P-Cr steel did not develop any pits/deep grooves on its surface even after the prolonged exposure to salt fog. The improved corrosion resistance of the Cu-P-Cr steel has been attributed to the presence of copper, phosphorus, and small amount of chromium in the dense, adherent rust layer on the surface of reinforcing steel bar. A schematic mechanism of charge transfer has been proposed to explain the improved corrosion resistance of the Cu-P-Cr alloyed TMT rebar.

  3. Tensile and Impact Toughness Properties of Gas Tungsten Arc Welded and Friction Stir Welded Interstitial Free Steel Joints

    NASA Astrophysics Data System (ADS)

    Lakshminarayanan, A. K.; Balasubramanian, V.

    2011-02-01

    Welded regions of interstitial free (IF) steel grades in the vicinity of weld center exhibits larger grains because of the prevailing thermal conditions during weld metal solidification. This often causes inferior weld mechanical properties. In the present study, tensile properties, charpy impact toughness, microhardness, microstructure, lowest hardness distribution profile, and fracture surface morphology of the gas tungsten arc welded (GTAW) and friction stir welded joints were evaluated, and the results are compared. From this investigation, it is found that friction stir welded joint of IF steel showed superior tensile and impact properties compared with GTAW joint, and this is mainly due to the formation of very fine, equiaxed microstructure in the weld zone.

  4. Fractography, fluidity, and tensile properties of aluminum/hematite particulate composites

    SciTech Connect

    Sharma, S.C.; Girish, B.M.; Kamath, R.; Satish, B.M.

    1999-06-01

    This paper examines the effect of hematite (iron oxide) particles on the fluidity of the molten composite as well as the tensile properties and fracture behavior of the solidified as-cast aluminum composites. The percentage of hematite in the composite was varied from 1 to 7% in steps of 2% by weight. The vortex method was employed to prepare the composites. It followed from the results obtained that the ultimate tensile strength and Young`s modulus of the composite increased while the liquid fluidity and solid ductility decreased with the increase in hematite content in the composite specimens. The fluidity of the liquid was greater in a metal mold than in a sand mold, and it decreased with an increase in reinforcing particle size and increased with pouring temperature. The presence of the reinforcing particles altered the fracture behavior of the solid composites considerably. Final fracture of the composite occurred due to the propagation of cracks through the matrix between the reinforcing particles.

  5. Spectroscopic analysis of radiation-generated changes in tensile properties of a polyetherimide film

    SciTech Connect

    Long, E.R. Jr.; Long, S.A.T.

    1985-05-01

    The effects of electron radiation on Ultem, a polyetherimide were studied for doses from 2 x 10 to the 9th power to 6 x 10 to the 9th power rad. Specimens were studied for tensile property testing and for electron paramagnetic resonance and infrared spectroscopic measurements of molecular structure. A Faraday cup design and a method for remote temperature measurement were developed. The spectroscopic data show that radiation caused dehydrogenation of methyl groups, rupture of main-chain ether linkage, and opening of imide rings, all to form radicals and indicate that the so-formed atomic hydrogen attached to phenyl radicals, but not to phenoxyl radicals, which would have formed hydroxyls. The observed decays of the radiation-generated phenoxyl, gem-dimethyl, and carbonyl radicals were interpreted as a combining of the radicals to form crosslinking. This crosslinking is the probable cause of the major reduction in the elongation of the tensile specimens after irradiation. Subsequent classical solubility tests indicate that the irradiation caused massive crosslinking.

  6. Tensile and fatigue strength properties of Kevlar 29 aramid/epoxy unidirectional composites

    SciTech Connect

    Zweben, C.

    1981-07-22

    Static and fatigue tensile strength properties of filament wound undirectional Kevlar 29/epoxy, typical of filament wound material used in flywheel rotors, were studied. Machining techniques were developed to minimize fiber fuzzing on edges. The static modulus, normalized to 70% fiber volume fraction is 8.87 x 10/sup 6/ psi. The major Poisson's ratio is 0.37. The static composite tensile strength, normalized to 70% fiber volume fraction is 200 x 10/sup 3/ psi, corresponding to a fiber stress at failure of 286 x 10/sup 3/ psi, which is good for materials having a very high fiber volume fraction. The S-N curve for R = 0.7 was found to be quite flat. Although the techniques used in this program had previously been employed successfully to study the fatigue behavior of Kevlar 29/epoxy and Kevlar 49/epoxy unidirectional materials, we were unable to overcome the persistent problem of cohesive material failure in the tab regions. The apparent reason for this is the very low interlaminar shear strength of the filament wound material. 16 figures.

  7. Microstructure Development in Electron Beam-Melted Inconel 718 and Associated Tensile Properties

    NASA Astrophysics Data System (ADS)

    Kirka, M. M.; Unocic, K. A.; Raghavan, N.; Medina, F.; Dehoff, R. R.; Babu, S. S.

    2016-03-01

    During the electron beam melting (EBM) process, builds occur at temperatures in excess of 800°C for nickel-base superalloys such as Inconel 718. When coupled with the temporal differences between the start and end of a build, a top-to-bottom microstructure gradient forms. Characterized in this study is a microstructure gradient and associated tensile property gradient common to all EBM Inconel 718 builds, the extent of which is dependent on build geometry and the specifics of a build's processing history. From the characteristic microstructure elements observed in EBM Inconel 718 material, the microstructure gradient can be classified into three distinct regions. Region 1 (top of a build) is comprised of a cored dendritic structure that includes carbides and Laves phase within the interdendritic regions. Region 2 is an intermediate transition zone characterized by a diffuse dendritic structure, dissolution of the Laves phase, and precipitation of δ needle networks within the interdendritic regions. The bulk structure (Region 3) is comprised of a columnar grain structure lacking dendritic characteristics with δ networks having precipitated within the grain interiors. Mechanically, at both 20°C and 650°C, the yield strength, ultimate tensile strength, and elongation at failure exhibit the general trend of increasing with increasing build height.

  8. Effect of boron on tensile properties of B2 BeAl

    NASA Technical Reports Server (NTRS)

    Crimp, M.; Vedula, K.

    1986-01-01

    Small additions of boron were shown to improve the room temperature ductility of the intermetallic compound Ni3Al. Boron is believed to segregate to the gain boundaries and strengthen them, allowing the inheret ductility of the grains to be achieved. The present study was undertaken to see if boron has a similar effect on the low temperature tensile properties of the equiatomic intermetallic compound FeAl. A binary alloy without boron is compared with an alloy containing 0.78 at % B (0.2 wt %) B, by tensile testing over the temperature range of 300 K to 640 K. Both alloys were processed by powder metallurgy. Results showed that 0.78 at % B addition to FeAl does indeed change the room temperature fracture mode from intergranular to transgranular, suggesting a strengthening of grain boundaries. The alloy containing boron is, however, still brittle at room temperature. A slight decrease in the ductile to brittle transition temperature is, nevertheless, observed. In addition a significant increase in strength of the alloy is observed with boron addition.

  9. Effect of organometallic clamp properties on the apparent diversity of tensile response of nanowires.

    PubMed

    Murphy, Kathryn F; Chen, Lisa Y; Gianola, Daniel S

    2013-06-14

    The influence of the experimental boundary conditions used for tensile testing of individual nanowires on the measured apparent mechanical response is reported. Using a microelectromechanical platform designed for in situ tensile testing, in combination with digital image correlation of sequences of scanning electron microscope images, the mechanical behavior of single crystalline Si, Pd, and Ge2Sb2Te5 nanowires was measured during load-unload cycles. In situ testing enables direct determination of the nanowire strain. Comparison of the direct strain with common metrics for apparent strain that include any compliance or slipping of the clamping materials (electron-beam induced Pt-containing deposits) highlights several different artifacts that may be manifested. Calculation of the contact stiffness is thus enabled, providing guidelines for both proper strain measurement and selection of clamping materials and geometries that facilitate elucidation of intrinsic material response. Our results suggest that the limited ability to tailor the stiffness of electron-beam induced deposits results from the predominance of the organic matrix in controlling its mechanical properties owing to relatively low Pt content and sparse morphology. PMID:23669193

  10. Structure and tensile properties of polypropylene/carbon nanotubes composites prepared by melt extrusion

    NASA Astrophysics Data System (ADS)

    Liu, Yanhui; Zuo, Jicheng; Qin, Jie; Li, Chengwu

    2014-09-01

    Polypropylene/carbon nanotubes (PP/CNTs) nancomposites were prepared with a single screw extruder by adding maleic anhydride-grafted poplypropylene (PP-g-MAH) as compatibilizer to polypropylene (PP) with different amounts of carbon nanotubes (CNTs) in the range of 0.1-0.7 wt.%. Structure and morphology of the prepared samples were examined by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), polarizing light microscopy (PLM) and X-ray diffraction (XRD). The results showed that PP spherulites decreased in size when CNTs were introduced into the polymer. Mechanical properties of the samples were also studied. Tensile tests showed that with increasing amount of CNTs the strain at break decreased whereas the Young's modulus was improved of 16.41 % to 36.05 % and tensile strength of 36.67 % to 64.70 % compared to pristine PP. The SEM microphotographs showed that majority of the CNTs were dispersed individually and oriented along the shear flow direction.

  11. Optical measurements of vocal fold tensile properties: implications for phonatory mechanics.

    PubMed

    Kelleher, Jordan E; Siegmund, Thomas; Chan, Roger W; Henslee, Erin A

    2011-06-01

    In voice research, in vitro tensile stretch experiments of vocal fold tissues are commonly employed to determine the tissue biomechanical properties. In the standard stretch-release protocol, tissue deformation is computed from displacements applied to sutures inserted through the thyroid and arytenoid cartilages, with the cartilages assumed to be rigid. Here, a non-contact optical method was employed to determine the actual tissue deformation of vocal fold lamina propria specimens from three excised human larynges in uniaxial tensile tests. Specimen deformation was found to consist not only of deformation of the tissue itself, but also deformation of the cartilages, as well as suture alignment and tightening. Stress-stretch curves of a representative load cycle were characterized by an incompressible Ogden model. The initial longitudinal elastic modulus was found to be considerably higher if determined based on optical displacement measurements than typical values reported in the literature. The present findings could change the understanding of the mechanics underlying vocal fold vibration. Given the high longitudinal elastic modulus the lamina propria appeared to demonstrate a substantial level of anisotropy. Consequently, transverse shear could play a significant role in vocal fold vibration, and fundamental frequencies of phonation should be predicted by beam theories accounting for such effects. PMID:21497355

  12. Microstructure Development in Electron Beam-Melted Inconel 718 and Associated Tensile Properties

    DOE PAGESBeta

    Kirka, M. M.; Unocic, K. A.; Raghavan, N.; Medina, F.; Dehoff, R. R.; Babu, S. S.

    2016-02-12

    During the electron beam melting (EBM) process, builds occur at temperatures in excess of 800°C for nickel-base superalloys such as Inconel 718. When coupled with the temporal differences between the start and end of a build, a top-to-bottom microstructure gradient forms. Characterized in this study is the microstructure gradient and associated tensile property gradient that are common to all EBM Inconel 718 builds. From the characteristic microstructure elements observed in EBM Inconel 718 material, the microstructure gradient can be classified into three distinct regions. Region 1 (top of a build) and is comprised of a cored dendritic structure that includesmore » carbides and Laves phase within the interdendritic regions. Region 2 is an intermediate transition zone characterized by a diffuse dendritic structure, dissolution of the Laves phase, and precipitation of δ needle networks within the interdendritic regions. The bulk structure (Region 3) is comprised of a columnar grain structure lacking dendritic characteristics with δ networks having precipitated within the grain interiors. Mechanically at both 20°C and 650° C, the yield strength, ultimate tensile strength, and elongation at failure exhibit the general trend of increasing with increasing build height.« less

  13. Microstructure and tensile properties of Fe3Al produced by combustion synthesis/hot isostatic pressing

    NASA Astrophysics Data System (ADS)

    Rabin, B. H.; Wright, R. N.

    1992-01-01

    Combustion synthesis was carried out in a hot isostatic press (HIP) in order to prepare near-theoretical density Fe3Al and Fe3Al + Cr alloys from elemental powder mixtures. The microstructures and room-temperature tensile properties of these materials were studied in the as-synthesized condition and after heat treatment. As-synthesized materials exhibit a fine, equiaxed grain structure with grain sizes typically less than 10 μm. Yield and ultimate tensile strengths were found to be significantly higher than what has been reported for conventionally processed materials having similar composition. Although lower ductility was generally observed, elongations exceeding 5 pct were obtained in heat-treated Cr-containing alloys. Fracture occurred predominantly by transgranular cleavage. The strengthening of these materials is attributed to the fine grain size resulting from combustion synthesis/HIP processing. Transmission electron microscopy (TEM) revealed the presence of two distinct populations of aluminum oxide particles in the material. Nanometer-sized oxides exist within grains that likely formed at prior iron particle boundaries, and a high density of larger oxides exist along grain boundaries that probably originated from surface oxides on the aluminum powder. The presence of the grain boundary oxides was qualitatively observed to provide resistance to grain growth.

  14. Spectroscopic analysis of radiation-generated changes in tensile properties of a polyetherimide film

    NASA Technical Reports Server (NTRS)

    Long, E. R., Jr.; Long, S. A. T.

    1985-01-01

    The effects of electron radiation on Ultem, a polyetherimide were studied for doses from 2 x 10 to the 9th power to 6 x 10 to the 9th power rad. Specimens were studied for tensile property testing and for electron paramagnetic resonance and infrared spectroscopic measurements of molecular structure. A Faraday cup design and a method for remote temperature measurement were developed. The spectroscopic data show that radiation caused dehydrogenation of methyl groups, rupture of main-chain ether linkage, and opening of imide rings, all to form radicals and indicate that the so-formed atomic hydrogen attached to phenyl radicals, but not to phenoxyl radicals, which would have formed hydroxyls. The observed decays of the radiation-generated phenoxyl, gem-dimethyl, and carbonyl radicals were interpreted as a combining of the radicals to form crosslinking. This crosslinking is the probable cause of the major reduction in the elongation of the tensile specimens after irradiation. Subsequent classical solubility tests indicate that the irradiation caused massive crosslinking.

  15. Development of nanostructured SUS316L-2%TiC with superior tensile properties

    NASA Astrophysics Data System (ADS)

    Sakamoto, T.; Kurishita, H.; Matsuo, S.; Arakawa, H.; Takahashi, S.; Tsuchida, M.; Kobayashi, S.; Nakai, K.; Terasawa, M.; Yamasaki, T.; Kawai, M.

    2015-11-01

    Structural materials used in radiation environments require radiation tolerance and sufficient mechanical properties in the controlled state. In order to offer SUS316L austenitic stainless steel with the assumed requirements, nanostructured SUS316L with TiC addition of 2% (SUS316L-2TiC) that is capable of exhibiting enhanced tensile ductility and flow strength sufficient for structural applications was fabricated by advanced powder metallurgical methods. The methods include MA (Mechanical Alloying), HIP (Hot Isostatic Pressing), GSMM (Grain boundary Sliding Microstructural Modification) for ductility enhancement, cold rolling at temperatures below Md (the temperature where the martensite phase occurs by plastic deformation) for phase transformation from austenite to martensite and heat treatment for reverse transformation from martensite to austenite. It is shown that the developed SUS316L-2TiC exhibits ultrafine grains with sizes of 90-270 nm, accompanied by TiC precipitates with 20-50 nm in grain interior and 70-110 nm at grain boundaries, yield strengths of 1850 to 900 MPa, tensile strengths of 1920 to 1100 MPa and uniform elongations of 0.6-21%, respectively, depending on the heat treatment temperature after rolling at -196 °C.

  16. Tensile, creep, and ABI tests on sn5%sb solder for mechanical property evaluation

    NASA Astrophysics Data System (ADS)

    Murty, K. Linga; Haggag, Fahmy M.; Mahidhara, Rao K.

    1997-07-01

    Sn5%Sb is one of the materials considered for replacing lead containing alloys for soldering in electronic packaging. We evaluated the tensile properties of the bulk material at varied strain-rates and temperatures (to 473K) to determine the underlying deformation mechanisms. Stress exponents of about three and seven were observed at low and high stresses, respectively, and very low activation energies for creep (about 16.7 and 37.7 kJ/mole) were noted. A maximum ductility of about 350% was noted at ambient temperature. Creep tests performed in the same temperature regime also showed two distinct regions, albeit with slightly different exponents (three and five) and activation energy (about 54.4 kJ/mole). Ball indentation tests were performed on the shoulder portions of the creep samples (prior to creep tests) using a Stress-Strain Microprobe@ (Advanced Technology Corporation) at varied indentation rates (strain-rates). The automated ball indentation (ABI) data were at relatively high strain-rates; however, they were in excellent agreement with creep data, while both these results deviated from the tensile test data. Work is planned to perform creep at high stresses at ambient and extend ABI tests to elevated temperatures.

  17. Reproducibility and Repeatability of Tensile and Low-Cycle Fatigue Properties in Propulsion Grade Hydrogen

    NASA Technical Reports Server (NTRS)

    Vesely, E. J.; Bhat, B. N.; McPherson, W. B.; Grethlein, C. E.; Jones, Clyde S. (Technical Monitor)

    2002-01-01

    Hydrogen has the potential of increased use in the future as an environmentally friendly fuel. It has, however, shown a tendency to embrittle some materials. To be used in a safe manner and to exploit its full potential, it will be necessary to develop a database of material properties in hydrogen environment. The tests needed to produce this data are costly to perform (tensile test cost 25 times more and low cycle fatigue test are 55 times as expensive). Moreover, there is presently a lack of universal test methods to ensure standardized data within the hydrogen community. Each of the industries that work with hydrogen (aerospace, petroleum, fuel cells, etc.) performs tests by their own laboratory-developed methods, thus rendering cross- comparisons of material property data highly questionable. It is extremely important that data generated in a hydrogen environment be done to a standard that reduces variance to a minimum and allows direct comparison of test results from different laboratories. Doing so will assure that all data generated can be used to further our understanding of the hydrogen effects and to make sure components/products designed for hydrogen are the safest and most reliable possible. This paper reviews the results of two 'round-robin' programs conducted by NASA-MSFC. These two programs examined the reproducibility and repeatability of tensile and low-cycle fatigue test results in high-pressure hydrogen environments. The studies indicated that even with the tightest controls available from current commercial standards, the reproducibility (between different laboratories) and repeatability (within a laboratory) results of the tensile tests exhibited five times the variance as in standard ambient air tests. The variance with the LCF tests were on the same order as with air tests, but that was due to the large variation present in the last Interlaboratory air program. The paper concludes with a recommendation for a program that would allow the

  18. Effect of boron on post irradiation tensile properties of reduced activation ferritic steel (F-82H) irradiated in HFIR

    SciTech Connect

    Shiba, Kiyoyuki; Suzuki, Masahide; Hishinuma, Akimichi; Pawel, J.E.

    1994-12-31

    Reduced activation ferritic/martensitic steel, F-82H (Fe-8Cr-2W-V-Ta), was irradiated in the High Flux Isotope Reactor (HFIR) to doses between 11 and 34 dpa at 400 and 500 C. Post irradiation tensile tests were performed at the nominal irradiation temperature in vacuum. Some specimens included {sup 10}B or natural boron (nB) to estimate the helium effect on tensile properties. Tensile properties including the 0.2% offset yield stress, the ultimate tensile strength, the uniform elongation and the total elongation were measured. The tensile properties were not dependent on helium content in specimens irradiated to 34 dpa, however {sup 10}B-doped specimens with the highest levels of helium showed slightly higher yield strength and less ductility than boron-free specimens. Strength appears to go through a peak, and ductility through a trough at about 11 dpa. The irradiation to more than 21 dpa reduced the strength and increased the elongation to the unirradiated levels. Ferritic steels are one of the candidate alloys for nuclear fusion reactors because of their good thermophysical properties, their superior swelling resistance, and the low corrosion rate in contact with potential breeder and coolant materials.

  19. J-integral fracture toughness, Tearing modulus and tensile properties of Vitamin E stabilized radiation crosslinked UHMWPE.

    PubMed

    Bellare, Anuj; Dorfman, Robert; Samuel, Ashwanth; Thornhill, Thomas S

    2016-08-01

    Radiation crosslinking of ultra-high molecular weight polyethylene (UHMWPE) increases its wear resistance in total joint replacement prostheses. Unfortunately, it is accompanied by a dose-dependent decrease in several mechanical properties. In this study, the tensile properties and fracture behavior of radiation crosslinked, Vitamin E stabilized UHMWPE was studied as a function of radiation dose. The Rice and Sorensen model, applicable to elastic-plastic materials, was utilized to obtain the initial crack driving force, J1c, steady state J-integral fracture toughness, Jss and the Tearing modulus. Tensile tests showed the dependence of tensile properties on radiation dose. Jss of non-crosslinked UHMWPE was higher than for crosslinked UHMWPE׳s but there was no dose dependent change in Jss whereas there was almost no change in J1c over the entire dose range. Finally, a monotonic decrease in Tearing modulus was observed with radiation dose. PMID:27128734

  20. Mechanical properties of individual InAs nanowires studied by tensile tests

    SciTech Connect

    Li, X.; Wei, X. L. E-mail: qingchen@pku.edu.cn; Xu, T. T.; Ning, Z. Y.; Shu, J. P.; Chen, Q. E-mail: qingchen@pku.edu.cn; Wang, X. Y.; Pan, D.; Zhao, J. H.; Yang, T.

    2014-03-10

    Mechanical properties of individual InAs nanowires (NWs) synthesized by metal organic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE) methods are studied by in-situ tensile tests in a scanning electron microscope and their fracture strength and Young's modulus are obtained. The two types of NWs both exhibit brittle fracture with a maximum elastic strain up to ∼10%. Their fracture strength distributes in a similar range of ∼2–5 GPa with a general trend of increasing with NW volume decrease, which is well described by Weibull statistic with a smaller Weibull modulus and a higher characteristic strength for MOCVD NWs. Young's modulus is determined to be 16–78 GPa with an average value of 45 GPa and no dependence on NW diameter for MOCVD NWs and 34–79 GPa with an average value of 58 GPa for MBE NWs.

  1. Tensile properties of vanadium alloys irradiated at 200{degrees}C in the HFIR

    SciTech Connect

    Chung, H.M.; Nowicki, L.; Smith, D.L.

    1997-08-01

    Vanadium alloys were irradiated in a helium environment to {approx}10 dpa at {approx}200{degrees}C in the High Flux Isotope Reactor (HFIR). This report presents results of postirradiation tests of tensile properties of laboratory heats of V-(1-18)Ti, V-4Cr-4Ti, V-8Cr-6Ti, V-9Cr-5Ti, V-3Ti-1Si, and V-3Ti-0.1C alloys. Because of significant loss of work-hardening capability, all alloys except V-18Ti exhibited a very low uniform plastic strain <1%. For V-Ti. The mechanism of the loss of work-hardening capability in the other alloys is not understood.

  2. Creep, thermal-cyclic and tensile properties of Nb1Zr to stainless steel transition joints

    NASA Astrophysics Data System (ADS)

    Chen, S.; Yu, W.; Zee, R. H.; Chin, B. A.

    1994-09-01

    Joining of Nb1Zr to austenitic type 316 stainless steel (SS) was investigated. Gas tungsten arc welding was conducted on sheet metals and tubing by lap welding 316 SS over Nb1Zr. Sound welds were produced by controlling heat input and through careful surface preparation. Satisfactory strength and ductility of the welded joints were found in the tensile tests at room temperature and 1000 K. Investigation of thermocycling effects showed that there was a small degradation in the mechanical properties of the joint after 100 thermal cycles between 300 and 1000 K under vacuum. Creep tests were performed on welded tubing joints at a temperature of 1000 K with internal pressures up to 6.9 MPa. Creep test results show that the welded joint has higher creep resistance than stainless steel. Furthermore, to improve the toughness of the Nb1Zr to 316 SS weld, the use of a vanadium interlayer was investigated.

  3. The effects of specimen width on tensile properties of triaxially braided textile composites

    NASA Technical Reports Server (NTRS)

    Masters, John E.; Ifju, Peter G.; Pastore, Christopher M.; Bogdanovich, Alexander E.

    1993-01-01

    The objective of this study was to examine the effect of the unit cell architecture on the mechanical response of textile reinforced composite materials. Specifically, the study investigated the effect of unit cell size on the tensile properties of 2D triaxially braided graphite epoxy laminates. The figures contained in this paper reflect the presentation given at the conference. They may be divided into four sections: (1) a short definition of the material system tested; (2) a statement of the problem and a review of the experimental results; (3) experimental results consist of a Moire interferometry study of the strain distribution in the material plus modulus and strength measurements; and (4) a short summary and a description of future work will close the paper.

  4. Mechanical properties of individual InAs nanowires studied by tensile tests

    NASA Astrophysics Data System (ADS)

    Li, X.; Wei, X. L.; Xu, T. T.; Ning, Z. Y.; Shu, J. P.; Wang, X. Y.; Pan, D.; Zhao, J. H.; Yang, T.; Chen, Q.

    2014-03-01

    Mechanical properties of individual InAs nanowires (NWs) synthesized by metal organic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE) methods are studied by in-situ tensile tests in a scanning electron microscope and their fracture strength and Young's modulus are obtained. The two types of NWs both exhibit brittle fracture with a maximum elastic strain up to ˜10%. Their fracture strength distributes in a similar range of ˜2-5 GPa with a general trend of increasing with NW volume decrease, which is well described by Weibull statistic with a smaller Weibull modulus and a higher characteristic strength for MOCVD NWs. Young's modulus is determined to be 16-78 GPa with an average value of 45 GPa and no dependence on NW diameter for MOCVD NWs and 34-79 GPa with an average value of 58 GPa for MBE NWs.

  5. Effect of strain rate on the tensile material properties of human placenta.

    PubMed

    Manoogian, Sarah J; Bisplinghoff, Jill A; McNally, Craig; Kemper, Andrew R; Santago, Anthony C; Duma, Stefan M

    2009-09-01

    Automobile crashes are the largest cause of injury death for pregnant females and the leading cause of traumatic fetal injury mortality in the United States. Computational models, useful tools to evaluate the risk of fetal loss in motor vehicle crashes, are based on a limited number of quasistatic material tests of the placenta. This study presents a total of 64 uniaxial tensile tests on coupon specimens from six human placentas at three strain rates. Material properties of the placental tissue were evaluated at strain rates of 0.07/s, 0.70/s, and 7.00/s. The test data have average failure strains of 0.34, 0.36, and 0.37, respectively. Failure stresses of 10.8 kPa, 11.4 kPa, and 18.6 kPa correspond to an increase in strain rate from 0.07/s to 7.0/s. The results indicate rate dependence only when comparing the highest strain rate of 7.0/s to either of the lower rates. There is no significant rate dependence between 0.07/s and 0.70/s. When compared with previous testing of placental tissue, the current study addresses the material response to more strain rates as well as provides a much larger set of available data. In summary, tensile material properties for the placenta have been determined for use in computational modeling of pregnant occupant kinematics in events ranging from low impact activities to severe impacts such as in motor vehicle crashes. PMID:19725697

  6. Influences of post weld heat treatment on tensile properties of friction stir welded AA2519-T87 aluminium alloy joints

    NASA Astrophysics Data System (ADS)

    Sabari, S. Sree; Balasubramanian, V.; Malarvizhi, S.; Reddy, G. Madusudhan

    2015-12-01

    AA 2519-T87 is an aluminium alloy that principally contains Cu as an alloying element and is a new grade of Al-Cu alloy system. This material is a potential candidate for light combat military vehicles. Fusion welding of this alloy leads to hot cracking, porosity and alloy segregation in the weld metal region. Friction stir welding (FSW) is a solid state joining process which can overcome the above mentioned problems. However, the FSW of age hardenable aluminium alloys results in poor tensile properties in the as-welded condition (AW). Hence, post weld heat treatment (PWHT) is used to enhance deteriorated tensile properties of FSW joints. In this work, the effect of PWHT, namely artificial ageing (AA) and solution treatment (ST) followed by ageing (STA) on the microstructure, tensile properties and microhardness were systematically investigated. The microstructural features of the weld joints were characterised using an optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The tensile strength and microhardness of the joints were correlated with the grain size, precipitate size, shape and its distribution. From the investigation, it was found that STA treatment is beneficial in enhancing the tensile strength of the FSW joints of AA2519-T87 alloy and this is mainly due to the presence of fine and densely distributed precipitates in the stir zone.

  7. Tensile and impact properties of vanadium-base alloys irradiated at <430°C

    NASA Astrophysics Data System (ADS)

    Chung, H. M.; Smith, D. L.

    1998-10-01

    Tensile and impact properties were investigated at <430°C on V-Cr-Ti, V-Ti-Si, and V-Ti alloys after irradiation to ≈2-46 dpa at 205-430°C in lithium or helium in the fast flux test facility (FFTF), high flux isotope reactor (HFIR), experimental breeder reactor II (EBR-II), and advanced test reactor (ATR). A 500-kg heat of V-4Cr-4Ti exhibited high ductile-brittle transition temperature and minimal uniform elongation as a result of irradiation-induced loss of work-hardening capability. Work-hardening capabilities of 30- and 100-kg heats of V-4Cr-4Ti varied significantly with irradiation conditions, although the 30-kg heat exhibited excellent impact properties after irradiation at ≈390-430°C. The origin of the significant variations in the work-hardening capability of V-4Cr-4Ti is not understood, although fabrication variables, annealing history, and contamination from the irradiation environment are believed to play important roles. A 15-kg heat of V-3Ti-1Si exhibited good work-hardening capability and excellent impact properties after irradiation at ≈390-430°C. Helium atoms, either charged dynamically or produced via transmutation of boron in the alloys, promote work-hardening capability in V-4Cr-4Ti and V-3Ti-1Si.

  8. Tensile impact properties of vanadium-base alloys irradiated at <430{degree}C.

    SciTech Connect

    Chung, H. M.

    1998-05-18

    Tensile and impact properties were investigated at <430 C on V-Cr-Ti, V-Ti-Si, and V-Ti alloys after irradiation to {approx}2-46 dpa at 205-430 C in lithium or helium in the Fast Flux Test Facility (FFTF), High Flux Isotope Reactor (HFIR), Experimental Breeder Reactor II (EBR-II), and Advanced Test Reactor (ATR). A 500-kg heat of V-4Cr-4Ti exhibited high ductile-brittle transition temperature and minimal uniform elongation as a result of irradiation-induced loss of work-hardening capability. Work-hardening capabilities of 30- and 100-kg heats of V-4Cr-4Ti varied significantly with irradiation conditions, although the 30-kg heat exhibited excellent impact properties after irradiation at {approx}390-430 C. The origin of the significant variations in the work-hardening capability of V-4Cr-4Ti is not understood, although fabrication variables, annealing history, and contamination from the irradiation environment are believed to play important roles. A 15-kg heat of V-3Ti-1Si exhibited good work-hardening capability and excellent impact properties after irradiation at {approx}390-430 C. Helium atoms, either charged dynamically or produced via transmutation of boron in the alloys, promote work-hardening capability in V-4Cr-4Ti and V-3Ti-1Si.

  9. Effect of Dermatan Sulfate on the Indentation and Tensile Properties of Articular Cartilage

    PubMed Central

    Hall, Melanie L.; Krawczak, David A.; Simha, Narendra K.; Lewis, Jack L.

    2009-01-01

    Objective This paper examines the hypothesis that the dermatan sulfate (DS) chain on decorin is a load carrying element in cartilage and that its damage or removal will alter the material properties. Methods To test this hypothesis, indentation and tensile testing of cartilage from bovine patella was performed before and after digestion with chondroitinase B (cB). Removal of significant amounts of DS by cB digestion was verified by Western blot analysis of proteoglycans extracted from whole and sectioned specimens. Specimens (control and treated) were subjected to a series of step-hold displacements. Elastic modulus during the step rise (rapid modulus) and at equilibrium (equilibrium modulus), and the relaxation function during each step were measured for test (cB and buffer) and control (buffer alone) conditions. Results cB had no effect on any of the viscoelastic mechanical properties measured, either in indentation or tension Conclusion Removing or damaging approximately 50% of the dermatan sulfate had no effect on the mechanical properties, strongly suggesting that dermatan sulfate either carries very low load or no load. PMID:19036614

  10. Natural cellulose fibers from switchgrass with tensile properties similar to cotton and linen.

    PubMed

    Reddy, Narendra; Yang, Yiqi

    2007-08-01

    We report the production and characteristics of natural cellulose fibers obtained from the leaves and stems of switchgrass. In this paper, the composition, structure and properties of fibers obtained from the leaves and stem of switchgrass have been studied in comparison to the common natural cellulose fibers, such as cotton, linen and kenaf. The leaves and stems of switchgrass have tensile properties intriguingly similar to that of linen and cotton, respectively. Fibers were obtained from the leaves and stems of switchgrass using a simple alkaline extraction and the structure and properties of the fibers were studied. Fibers obtained from switchgrass leaves have crystallinity of 51%, breaking tenacity of 5.5 g per denier (715 MPa) and breaking elongation of 2.2% whereas the corresponding values for fibers obtained from switchgrass stems are 46%, 2.7 g per denier and 6.8%, respectively. Switchgrass is a relatively easy to grow and high yield biomass crop that can be source to partially substitute the natural and synthetic fibers currently in use. We hope that this research will stimulate interests in using switchgrass as a novel fiber crop in addition to being promoted as a potential source for biofuels. PMID:17221888

  11. Effect of Strain Rate on Tensile Properties of Carbon Fiber Epoxy-Impregnated Bundle Composite

    NASA Astrophysics Data System (ADS)

    Naito, Kimiyoshi

    2014-03-01

    The tensile tests for high tensile strength polyacrylonitrile (PAN)-based (T1000GB) carbon fiber epoxy-impregnated bundle composite at various strain rates ranging from 3.33 × 10-5 to 6.0 × 102 s-1 (various crosshead speeds ranging from 8.33 × 10-7 to 1.5 × 101 m/s) were investigated. The statistical distributions of the tensile strength were also evaluated. The results clearly demonstrated that the tensile strength of bundle composite slightly increased with an increase in the strain rate (crosshead speed) and the Weibull modulus of tensile strength for the bundle composite decreased with an increase in the strain rate (crosshead speed), there is a linear relation between the Weibull modulus and the average tensile strength on log-log scale.

  12. Dependence of the tensile properties of 316 L parent material and welds on implanted hydrogen and/or helium

    NASA Astrophysics Data System (ADS)

    Schroeder, Herbert; Liu, Wanpei

    1992-09-01

    The interest in the low temperature tensile properties of candidate alloys for first wall and blanket structures of future fusion devices is due to the possible low pressure water cooling and the associated low operation temperature in recent design studies. Therefore, the tensile properties of hydrogen and/or helium implanted 316 L stainless steel and its weldments as a function of gas concentrations and temperature were investigated. The main effects of the implantation are hardening, resulting in large increases of the yield strength proportional to the implanted gas concentration, and a gradual decrease of the corresponding rupture strain. The ultimate tensile stresses are less affected. The effect of helium implantation seems to be more pronounced than that of hydrogen implantation. At 673 K most of the implantation induced changes are recovered. Generally parent material and welds still show large ductility (≥20%) under all conditions investigated.

  13. Effects of La addition on the microstructure and tensile properties of Al-Si-Cu-Mg casting alloys

    NASA Astrophysics Data System (ADS)

    Lu, Tao; Pan, Ye; Wu, Ji-li; Tao, Shi-wen; Chen, Yu

    2015-04-01

    The effects of La addition on the microstructure and tensile properties of B-refined and Sr-modified Al-11Si-1.5Cu-0.3Mg casting alloys were investigated. With a trace addition of La (0.05wt%-0.1wt%), the mutual poisoning effect between B and Sr can be neutralized by the formation of LaB6 rather than SrB6. By employing a La/B weight ratio of 2:1, uniform microstructures, which are characterized by well refined α-Al grains and adequately modified eutectic Si particles as well as the incorporation of precipitated strengthening intermetallics, are obtained and lead to appreciable tensile properties with an ultimate tensile strength of 270 MPa and elongation of 5.8%.

  14. Solubility, tensile, and color properties of modified soy protein isolate films.

    PubMed

    Rhim, J W; Gennadios, A; Handa, A; Weller, C L; Hanna, M A

    2000-10-01

    Protein solubility (PS) values of different soy protein isolate (SPI) films were determined in water, 0.01 N HCl, 0.01 N NaOH, 4 M urea, and 0.2 M 2-mercaptoethanol. Tensile and color (L, a, and b values) properties of films also were determined. Control films were cast from heated (70 degrees C for 20 min), alkaline (pH 10) aqueous solutions of SPI (5 g/100 mL of water) and glycerin (50% w/w of SPI). Additional films were cast after incorporation of dialdehyde starch (DAS) at 10% w/w of SPI or small amounts of formaldehyde in the film-forming solutions. Also, control film samples were subjected to heat curing (90 degrees C for 24 h), UV radiation (51.8 J/m(2)), or adsorption of formaldehyde vapors. PS of control films was highest (P < 0.05) in 2-mercaptoethanol, confirming the importance of disulfide bonds in SPI film formation. All treatments were effective in reducing (P < 0.05) film PS in all solvents. Both DAS and adsorbed formaldehyde rendered the protein in films practically insoluble in all solvents. Adsorption of formaldehyde vapors and heat curing also substantially increased (P < 0.05) film tensile strength from 8.2 to 15.8 or 14.7 MPa, respectively. However, heat curing decreased (P < 0.05) film elongation at break from 30 to 6%. Most treatments had small but significant (P < 0.05) effects on b color values, with DAS-containing films having the greatest (P < 0. 05) mean b value (most yellowish). Also, DAS-containing, heat-cured, and UV-irradiated films were darker, as evidenced by their lower (P < 0.05) L values, than control films. It was demonstrated that PS of SPI films can be notably modified through chemical or physical treatments prior to or after casting. PMID:11052759

  15. The tensile strength properties of CFRPs and GRRPs for Unnes electric car body material

    NASA Astrophysics Data System (ADS)

    Khumaedi, Muhammad; Sumbodo, Wirawan; Widodo, Rahmat Doni

    2016-04-01

    This paper describes composite materials tensile testing of electric car body material. The UNNES electric car body must be developed using a high strength and lightweight material. A fiber-reinforced plastic composite is widely used for the concerned objective. Selection of the type of composites, variations in fiber orientation, and the number of fiber layers will affect the tensile strength of the material. Composite materials use Carbon-fiber-reinforced plastics (CFRPs) and glass-fiber-reinforced plastics (GFRPs) variation to the fiber areal weight, variations in fiber orientation and the number of fiber layers. The CFRPs areal weight consists of 230 gsm and 400 gsm. The GFRPsareal weight consists of 400 gsm and 600 gsm. Fibre orientationsconsist of 0° and 45°. Number of fiber layers consists of one layer and two layers. Various variations were then tested to figure out their tensile to get ultimate tensile strength of materials. Standard test method for tensile test was conducted using ASTM D3039. Tensile specimen geometry used a type of balanced and symmetric fiber orientation, with 25mm in width, 250 mm in length, and 2.5 mm in thickness. The result shows that the more fiber areal weight and the layer number were used, the more its tensile strength would increase, beside it increased the ultimate tensile strength of the material for both glass and carbon fiber with 0o and 45o fiber arientation. Fiber plain wave with 45o has greater tensile strength compared to any other variation.

  16. Effects of high-dose gamma irradiation on tensile properties of human cortical bone: Comparison of different radioprotective treatment methods.

    PubMed

    Allaveisi, Farzaneh; Mirzaei, Majid

    2016-08-01

    There are growing interests in the radioprotective methods that can reduce the damaging effects of ionizing radiation on sterilized bone allografts. The aim of this study was to investigate the effects of 50kGy (single dose, and fractionated) gamma irradiation, in presence and absence of l-Cysteine (LC) free radical scavenger, on tensile properties of human femoral cortical bone. A total of 48 standard tensile test specimens was prepared from diaphysis of femurs of three male cadavers (age: 52, 52, and 54 years). The specimens were assigned to six groups (n=8) according to different irradiation schemes, i.e.; Control (Non-irradiated), LC-treated control, a single dose of 50kGy (sole irradiation), a single dose of 50kGy in presence of LC, 10 fractions of 5kGy (sole irradiation), and 10 fractions of 5kGy in presence of LC. Uniaxial tensile tests were carried out to evaluate the variations in tensile properties of the specimens. Fractographic analysis was performed to examine the microstructural features of the fracture surfaces. The results of multivariate analysis showed that fractionation of the radiation dose, as well as the LC treatment of the 50kGy irradiated specimens, significantly reduced the radiation-induced impairment of the tensile properties of the specimens (P<0.05). The fractographic observations were consistent with the mechanical test results. In summary, this study showed that the detrimental effects of gamma sterilization on tensile properties of human cortical bone can be substantially reduced by free radical scavenger treatment, dose fractionation, and the combined treatment of these two methods. PMID:27124804

  17. Experimental and Numerical Analysis of the Effects of Curing Time on Tensile Mechanical Properties of Thin Spray-on Liners

    NASA Astrophysics Data System (ADS)

    Guner, D.; Ozturk, H.

    2016-08-01

    The effects of curing time on tensile elastic material properties of thin spray-on liners (TSLs) were investigated in this study. Two different TSL products supplied by two manufacturers were tested comparatively. The "dogbone" tensile test samples that were prepared in laboratory conditions with different curing times (1, 7, 14, 21, and 28 days) were tested based on ASTM standards. It was concluded that longer curing times improves the tensile strength and the Young's Modulus of the TSLs but decreases their elongation at break. Moreover, as an additional conclusion of the testing procedure, it was observed that during the tensile tests, the common malpractice of measuring sample displacement from the grips of the loading machine with a linear variable displacement transducer versus the sample's gauge length had a major impact on modulus and deformation determination of TSLs. To our knowledge, true stress-strain curves were generated for the first time in TSL literature within this study. Numerical analyses of the laboratory tests were also conducted using Particle Flow Code in 2 Dimensions (PFC2D) in an attempt to guide TSL researchers throughout the rigorous PFC simulation process to model support behaviour of TSLs. A scaling coefficient between macro- and micro-properties of PFC was calculated which will help future TSL PFC modellers mimic their TSL behaviours for various tensile loading support scenarios.

  18. Transport and tensile properties of compression-molded wheat gluten films.

    PubMed

    Gällstedt, Mikael; Mattozzi, Alessandro; Johansson, Eva; Hedenqvist, Mikael S

    2004-01-01

    Mechanical and transport properties were assessed on wheat gluten films with a glycerol content of 25-40%, prepared by compression molding for 5-15 min at temperatures between 90 and 130 degrees C. Effects of storing the films up to 24 days, in 0 and 50% relative humidity (RH), were assessed by tensile measurements. The films were analyzed with respect to methanol zero-concentration diffusivity, oxygen permeability (OP), water vapor permeability (WVP), Cobb60 and sodium dodecyl sulfate (SDS) solubility coupled with sonication. The SDS solubility and methanol diffusivity were lower at the higher molding temperature. Higher glycerol content resulted in higher OP (90-95% RH), WVP, and Cobb60 values, due to the plasticizing and hygroscopic effects. Higher glycerol contents gave a lower fracture stress, lower Young's modulus, lower fracture strain, and less strain hardening. The mold time had less effect on the mechanical properties than mold temperature and glycerol content. The fracture stress and Young's modulus increased and the fracture strain decreased with decreasing moisture content. PMID:15360319

  19. Radial tensile properties of the lumbar annulus fibrosus are site and degeneration dependent.

    PubMed

    Fujita, Y; Duncan, N A; Lotz, J C

    1997-11-01

    We conducted an in vitro study of the radial tensile properties of the annulus fibrosus. The stress-strain response was nonlinear, with a mean tangent modulus of 0.19 MPa at zero strain and 0.47 MPa at 70% of the yield strain. We also investigated whether these properties varied as a function of location within the disc and degree of degeneration. Specimens harvested from the middle layers of the annulus were stiffer and failed at smaller strain magnitudes than those from the inner or outer annulus (analysis of covariance, p < 0.05). Differences due to degeneration were evident; degenerated discs had a 30% decrease in yield and ultimate stress compared with normal discs. Similarity between our data and those reported for the annulus in compression suggests that these values reflect the material behavior of the interlaminar matrix and are an order of magnitude smaller than values used in previous analytical representations of this tissue. We expect that awareness of these data will result in improved understanding of the physical behavior and tolerance to injury of the annulus fibrosus. PMID:9497805

  20. Tensile properties of craniofacial tendons in the mature and aged zebrafish.

    PubMed

    Shah, Rishita R; Nerurkar, Nandan L; Wang, Calvin C; Galloway, Jenna L

    2015-06-01

    The zebrafish Danio rerio is a powerful model for the study of development, regenerative biology, and human disease. However, the analysis of load-bearing tissues such as tendons and ligaments has been limited in this system. This is largely due to technical limitations that preclude accurate measurement of their mechanical properties. Here, we present a custom tensile testing system that applies nano-Newton scale forces to zebrafish tendons as small as 1 mm in length. Tendon properties were remarkably similar to mammalian tendons, including stress-strain nonlinearity and a linear modulus (515 ± 152 MPa) that aligned closely with mammalian data. Additionally, a simple exponential constitutive law used to describe tendon mechanics was successfully fit to zebrafish tendons; the associated material constants agreed with literature values for mammalian tendons. Finally, mature and aged zebrafish comparisons revealed a significant decline in mechanical function with age. Based on the exponential constitutive model, age-related changes were primarily caused by a reduction in nonlinearity (e.g., changes in collagen crimp or fiber recruitment). These findings demonstrate the utility of zebrafish as a model to study tendon biomechanics in health and disease. Moreover, these findings suggest that tendon mechanical behavior is highly conserved across vertebrates. PMID:25665155

  1. Tensile properties of craniofacial tendons in the mature and aged zebrafish

    PubMed Central

    Shah, Rishita R.; Nerurkar, Nandan L.; Wang, Calvin; Galloway, Jenna L.

    2015-01-01

    The zebrafish Danio rerio is a powerful model for the study of development, regenerative biology, and human disease. However, the analysis of load-bearing tissues such as tendons and ligaments has been limited in this system. This is largely due to technical limitations that preclude accurate measurement of their mechanical properties. Here, we present a custom tensile testing system that applies nano-Newton scale forces to zebrafish tendons as small as 1 mm in length. Tendon properties were remarkably similar to mammalian tendons, including stress-strain nonlinearity and a linear modulus (515±152 MPa) that aligned closely with mammalian data. Additionally, a simple exponential constitutive law used to describe tendon mechanics was successfully fit to zebrafish tendons; the associated material constants agreed with literature values for mammalian tendons. Finally, mature and aged zebrafish comparisons revealed a significant decline in mechanical function with age. Based on the exponential constitutive model, age related changes were primarily caused by a reduction in nonlinearity (e.g. changes in collagen crimp or fiber recruitment). These findings demonstrate the utility of zebrafish as a model to study tendon biomechanics in health and disease. Moreover, these findings suggest that tendon mechanical behavior is highly conserved across vertebrates. PMID:25665155

  2. Simulation of the tensile properties of silica aerogels: the effects of cluster structure and primary particle size.

    PubMed

    Liu, Qiang; Lu, Zixing; Zhu, Man; Yuan, Zeshuai; Yang, Zhenyu; Hu, Zijun; Li, Junning

    2014-09-01

    A new two-level model is proposed to investigate the relationship between the mechanical properties and microstructure of silica aerogels. This two-level model consists of the particle-particle interaction model and the cluster structure model. The particle-particle interaction model is proposed to describe interactions between primary particles, in which the polymerization reaction between primary particles is considered. The cluster structure model represents the geometrical structure of silica aerogels, and it is established using a modified diffusion-limited colloid aggregation (DLCA) algorithm. This two-level model is used to investigate the tensile behavior of silica aerogels based on the discrete element method (DEM). The numerical results show that the primary particle size has significant effects on the elastic modulus and tensile strength of silica aerogels. Moreover, the power-law relationships between tensile properties and aerogel density are dependent on the variation of the primary particle radius with density. The present results can explain the difference among different experimental exponents to a certain extent. In comparison with experimental data within a wide density range, this two-level model provides good quantitative estimations of the elastic modulus and tensile strength of silica aerogels after the size effects of the primary particle are considered. This paper provides a fundamental understanding of the relationship between the mechanical properties and microstructure of silica aerogels. The two-level model can be extended to study the mechanical properties of other aerogels and aerogel composites. PMID:25022232

  3. Effect of fiber treatments on tensile and thermal properties of starch/ethylene vinyl alcohol copolymers/coir biocomposites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of different fiber treatments, namely washing with water, alkali treatment (mercerization) and bleaching, on mechanical and thermal properties of starch/EVA/coir biocomposites were evaluated by tensile tests and thermogravimetry (TG), respectively. Additionally, the fiber/matrix interfac...

  4. Effect of Air and Vacuum Storage on the Tensile Properties of X-Ray Exposed Aluminized-FEP

    NASA Technical Reports Server (NTRS)

    deGroh, Kim K.; Gummow, Jonathan D.

    2000-01-01

    Metallized Teflon(Registered Trademark) FEP (fluorinated ethylene propylene), a common spacecraft thermal control material, from the exterior layer of the Hubble Space Telescope (HST) has become embrittled and suffers from extensive cracking. Teflon samples retrieved during Hubble servicing missions and from the Long Duration Exposure Facility (LDEF) indicate that there may be continued degradation in tensile properties over time. An investigation has been conducted to evaluate the effect of air and vacuum storage on the mechanical properties of x-ray exposed FEP. Aluminized-FEP (Al-FEP) tensile samples were irradiated with 15.3 kV Cu x-rays and stored in air or under vacuum for various time periods. Tensile data indicate that samples stored in air display larger decreases in tensile properties than for samples stored under vacuum. Air-stored samples developed a hazy appearance, which corresponded to a roughening of the aluminized surface. Optical property changes were also characterized. These findings indicate that air exposure plays a role in the degradation of irradiated FEP, therefore proper sample handling and storage is necessary with materials retrieved from space.

  5. Influence of adipic acid on tensile and morphology properties of linear low density polyethylene/rambutan peels flour blends

    NASA Astrophysics Data System (ADS)

    Nadhirah, A. A.; Sam, S. T.; Noriman, N. Z.; Ragunathan, S.; Ismail, H.

    2015-07-01

    This study investigate about the tensile and morphological properties of degradable polymer produced from linear low density polyethylene/rambutan peel flour (LLDPE/RPF) blends and adipic acid (AA) was used as a compatibilizer by varying the rambutan peel flour (RPF) amount from 0-25wt%. The samples were subjected to tensile and morphological tests. AA compatibilized showed higher strength compared to uncompatibilized blends. The Young's modulus for LLDPE/RPF blends increased with increasing flour content. However, the addition of adipic acid had reduced the Young's Modulus.

  6. Tensile mechanical and creep properties of Descemet's membrane and lens capsule.

    PubMed

    Danielsen, Carl Christian

    2004-09-01

    Descemet's membrane (DM) and the lens capsule (LC) are two ocular basement membrane structures which in comparison with other basement membranes have exceptional thicknesses which increase with age. Both membranes are supposed to contain networks of type IV collagen and laminin linked together with nidogen/entactin and containing other glycoproteins and proteoglycans. DM is a unique basement membrane which in addition contains fine filaments of type VIII collagen arranged in a hexagonal lattice. The mechanical functions of the LC are in lens suspension and accommodation, and its mechanical properties, previously investigated, are of great interest from a surgical point of view. DM serves as an endothelial basement membrane. Otherwise, its physiological function is unknown but may be one of mechanical support, filtration, or fluid barrier. Data on the mechanical properties of DM or the supramolecular assembly of type VIII collagen are very scarce or absent. The aim of this study was to determine and compare the mechanical properties of the two ocular membranes in order to elucidate the properties of DM in the light of those of LC. The human eyes were from testamentary donors and rat, cow, and sow eyes were obtained from normal animals. The tensile mechanical properties were determined by a volume-strain procedure and creep properties by subjecting the membranes from the latter three species to a constant axial stress. In rat, cow, and sow, DM was less strained to obtain a fixed moderate stress value (0.5 MPa) and showed to be 3.4- to 5.2-fold stiffer and to attain 2.7- to 4.6-fold higher stress at a strain value of 0.10 when compared with LC. The maximal strain, stiffness and stress were found to be less than those of the LC. In humans, DM and LC showed very similar mechanical properties. The instantaneous creep of DM was found to be less than that of LC indicating a higher stiffness of DM in the axial direction. In conclusion, depending on the species, DM showed to

  7. Optimization of high filler loading on tensile properties of recycled HDPE/PET blends filled with rice husk

    NASA Astrophysics Data System (ADS)

    Chen, Ruey Shan; Ahmad, Sahrim; Ghani, Mohd Hafizuddin Ab; Salleh, Mohd Nazry

    2014-09-01

    Biocomposites of recycled high density polyethylene / recycled polyethylene terephthalate (rHDPE/rPET) blend incorporated with rice husk flour (RHF) were prepared using a corotating twin screw extruder. Maleic anhydride polyethylene (MAPE) was added as a coupling agent to improve the fibre-matrix interface adhesion. The effect of high filler loadings (50-90 wt%) on morphology and tensile properties of compatibilized rHDPE/rPET blend was investigated. The results of our study shown that composite with 70 wt% exhibited the highest tensile strength and Young's modulus, which are 22 MPa and 1752 MPa, respectively. The elongation at break decreased with increasing percentage of RHF. SEM micrograph confirmed fillers dispersion, morphological interaction and enhanced interfacial bonding between recycled polymer blends and rice husk. It can be concluded that the optimum RHF content is 70 wt% with maximum tensile strength.

  8. Effect of prior creep at 1365 K on the room temperature tensile properties of several oxide dispersion strengthened alloys

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. D.

    1977-01-01

    An experimental study was conducted to determine whether oxide dispersion-strengthened (ODS) Ni-base alloys in wrought bar form are subject to creep degradation effects similar to those found in thin-gage sheet. The bar products evaluated included ODS-Ni, ODS-NiCr, and advanced ODS-NiCrAl types; the alloys included microstructures ranging from an essentially perfect single crystal to a structure consisting of very small elongated grains. Tensile test specimens were exposed to creep at various stress levels at 1365 K and then tensile tested at room temperature. Low residual tensile properties, change in fracture mode, appearance of dispersoid free bands, grain boundary cavitation, and/or internal oxidation are interpreted as creep degradation effects. The amount of degradation depends on creep strain, and degradation appears to be due to diffusional creep which produces dispersoid free bands around grain boundaries acting as vacancy sources.

  9. Tensile properties of AZ11A-0 magnesium-alloy sheet under rapid-heating and constant temperature

    NASA Technical Reports Server (NTRS)

    Kurg, Ivo M

    1956-01-01

    Specimens of AZ31A-0 magnesium alloy sheet were heated to rupture at nominal rates of 0.2 F to 100 F per second under constant tensile load conditions. The data are presented and compared with the results of conventional tensile stress-strain tests at elevated temperatures after 1.2-hour exposure. A temperature-rate parameter was used to construct master curves from which stresses and temperatures for yield and rupture can be predicted under rapid-heating conditions. A comparison of the elevated-temperature tensile properties of AZ31A-0 and HK31XA-H24 magnesium-alloy sheet under both constant-temperature and rapid-heating conditions is included.

  10. Microstructures and tensile properties of 304 steel with dual nanocrystalline and microcrystalline austenite content prepared by aluminothermic reaction casting

    NASA Astrophysics Data System (ADS)

    La, Peiqing; Wei, Fuan; Lu, Xuefeng; Shi, Ting; Chu, Chenggang; Wei, Yupeng; Wang, Hongding

    2014-08-01

    The microstructures of 304 stainless steels with different amounts of nanocrystalline and microcrystalline austenite prepared by an aluminothermic reaction casting, without and with annealing at 1073 K for 8 h, have been investigated by X-ray diffraction, an electron probe micro-analyser, a transmission electron microscope and a scanning electron microscope. The steels, both without and with annealing, consisted of different dual nanocrystalline and microcrystalline austenite combinations and a little nanocrystalline δ ferrite, while the average grain size of the nanocrystalline austenite increased from 19 to 26 nm and volume fraction of the microcrystalline austenite increased from 17 to 30% after annealing. The tensile strength of the steel was dramatically increased from 500 to 1000 MPa and the tensile elongation ratio increased from 8 to 12% after annealing. However, the tensile strength was decreased to 600 MPa and the tensile elongation ratio increased from 12 to 22% after an annealing at 1273 K. The combination of dual nanocrystalline and microcrystalline austenite obtained after the annealing at 1073 K results in the best tensile properties.

  11. High Temperature Tensile Properties and Fatigue Behavior of a Melt-Infiltrated SiC/SiC Composite

    NASA Technical Reports Server (NTRS)

    Kalluri, Sreeramesh; Calomino, Anthony M.; Brewer, David N.; Kiraly, Louis J. (Technical Monitor)

    2002-01-01

    High temperature fatigue behavior of a woven, SiC/SiC ceramic matrix composite (CMC) was investigated in air at two temperatures. The reinforcement for the CMC consisted of 5HS Sylramic(Trademark) fabric with a [0deg/90deg]4s lay-up. The SiC matrix material was infiltrated into the fiber-preform with a slurry-cast, melt-infiltration process. Tensile and fatigue test specimens were machined from the CMC plates. Initially tensile tests were conducted to obtain the average values of tensile properties at 1038 and 1204 C. Subsequently, low-cycle fatigue (LCF) tests with zero and two-hour hold-times at the maximum stress were conducted at the same two temperatures. Fatigue life data generated in the LCF tests were used to determine the geometric mean fatigue lives. In this paper, the tensile behavior and the fatigue durability of the CMC determined under different loading conditions are documented. In addition, reductions observed in the cyclic lives of the composite due to the two hour hold-time at maximum tensile stress are discussed.

  12. Tensile and impact properties of V-4Cr-4Ti alloy heats 832665 and 832864

    NASA Astrophysics Data System (ADS)

    Bray, T. S.; Tsai, H.; Nowicki, L. J.; Billone, M. C.; Smith, D. L.; Johnson, W. R.; Trester, P. W.

    2000-12-01

    Two large heats of V-4Cr-4Ti alloy were produced in the US in the past few years. The first, 832665, was a 500 kg heat procured by the US Department of Energy for basic fusion structural materials research. The second, 832864, was a 1300 kg heat procured by General Atomics for the DIII-D radiative divertor upgrade. Both heats were produced by Oremet-Wah Chang (previously Teledyne Wah Chang of Albany). Tensile properties up to 800°C and Charpy V-notch impact properties down to liquid nitrogen temperature were measured for both heats. The product forms tested for both heats were rolled sheets annealed at 1000°C for 1 h in vacuum. Testing results show the behavior of the two heats to be similar and the reduction of strengths with temperature to be insignificant up to at least 750°C. Ductility of both materials is good in the test temperature range. Impact properties for both heats are excellent - no brittle failures at temperatures above -150°C. Compared to the data for previous smaller laboratory heats of 15-50 kg, the results show that scale-up of vanadium alloy ingot production to sizes useful for reactor blanket design can be successfully achieved as long as reasonable process control is implemented (H. Tsai, et al., Fusion Materials Semiannual Progress Report for Period Ending 30th June 1998, DOE/ER-0313/24, p. 3; H. Tsai, et al., Fusion Materials Semiannual Progress Report for Period Ending 31st December 1998, DOE/ER-0313/25, p. 3).

  13. Dynamic Tensile Loading Improves the Functional Properties of Mesenchymal Stem Cell-Laden Nanofiber-Based Fibrocartilage

    PubMed Central

    Baker, Brendon M.; Shah, Roshan P.; Huang, Alice H.

    2011-01-01

    Fibrocartilaginous tissues such as the meniscus serve critical load-bearing roles, relying on arrays of collagen fibers to resist tensile loads experienced with normal activity. As these structures are frequently injured and possess limited healing capacity, there exists great demand for tissue-engineered replacements. Toward recreating the structural features of these anisotropic tissues in vitro, we employ scaffolds composed of co-aligned nanofibers that direct mesenchymal stem cell (MSC) orientation and the formation of organized extracellular matrix (ECM). Concomitant with ECM synthesis, the mechanical properties of constructs increase with free-swelling culture, but ultimately failed to achieve equivalence with meniscal fibrocartilage. As mechanical forces are essential to the development and maintenance of musculoskeletal tissues, this work examined the effect of cyclic tensile loading on MSC-laden nanofibrous constructs. We hypothesized that loading would modulate the transcriptional behavior of MSCs, spur the deposition of ECM, and lead to enhancements in construct mechanical properties compared to free-swelling controls. Fiber-aligned scaffolds were seeded with MSCs and dynamically loaded daily in tension or maintained as nonloaded controls for 4 weeks. With mechanical stimulation, fibrous gene expression increased, collagen deposition increased, and the tensile modulus increased by 16% relative to controls. These results show that dynamic tensile loading enhances the maturation of MSC-laden aligned nanofibrous constructs, suggesting that recapitulation of the structural and mechanical environment of load-bearing tissues results in increases in functional properties that can be exploited for tissue engineering applications. PMID:21247342

  14. Effect of Orientation on Tensile Properties of Inconel 718 Block Fabricated with Electron Beam Freeform Fabrication (EBF3)

    NASA Technical Reports Server (NTRS)

    Bird, R. Keith; Atherton, Todd S.

    2010-01-01

    Electron beam freeform fabrication (EBF3) direct metal deposition processing was used to fabricate an Inconel 718 bulk block deposit. Room temperature tensile properties were measured as a function of orientation and location within the block build. This study is a follow-on activity to previous work on Inconel 718 EBF3 deposits that were too narrow to allow properties to be measured in more than one orientation

  15. Tensile material properties of human tibia cortical bone effects of orientation and loading rate.

    PubMed

    Kemper, Andrew R; McNally, Craig; Manoogian, Sarah J; Duma, Stefan M

    2008-01-01

    The purpose of this study was to quantify effects of both specimen orientation and loading rate on the tensile material properties for human tibia cortical bone in a controlled study. This study presents 25 human tibia cortical bone coupon tests obtained from the mid-diaphysis of two fresh frozen male human cadavers: 11 axial and 14 lateral. The primary component for the tension coupon testing was a high rate servo-hydraulic Material Testing System (MTS) with a custom slack adaptor. The specimen were loaded at a constant strain rate of approximately 0.05 strains/s, 0.5 strains/s, or 5.0 strains/s. Axial specimens were found to have a significantly larger ultimate stress and ultimate strain compared to lateral specimens for all loading rates, and a significantly larger modulus for low and high loading rates. This finding illustrates the anisentropic behavior of bone over a range of strain rates, which is attributed to the microstructure of the bone and the osteon orientation along the long axis of the bone. With respect to loading rate, both axial and lateral specimens showed significant increases in the modulus and significant decreases in ultimate strain with increased loading rate. Although not significant, axial specimens showed another traditional viscoelastic trend, with ultimate stress increasing with increased loading rate. PMID:19141952

  16. Effect of low temperatures on tensile properties of ultrathin copper films

    NASA Astrophysics Data System (ADS)

    Guo, Qiao-Neng; Pan, Ernie; Yang, Shi-E.; Wang, Mingxing; Sun, Qiang; Wang, Jie-Fang; Jia, Yu

    2014-03-01

    The recent developments in MEMS have created a requirement for comprehending the mechanical properties of copper thin films. Moreover, the serviceability temperature of the films used for space research, superconductivity and so on is mainly low temperature. Thus, the molecular dynamics is employed to simulate the mechanical responses of single-crystal copper thin films under uniaxial tensile loading in different low temperature environments. With varying applied temperatures to the thin films, the variation of the maximum stress, Young's modulus and maximal potential energy is characterized and three different deformation mechanisms in the low temperature range from 40 to 250 K are identified. These different mechanisms of copper films in different temperature ranges are then explained via the continuum damage mechanics based on the evolutionary features of the slip and twin in the thin film. It is concluded that at temperatures above 200 K normal slip process occurs; whereas at temperatures below 70 K, twin nucleation process appears. However, when the temperature is between 70 K and 200 K, both twin and slip processes happen. Project supported by the National Natural Science Foundation of China (Grant No. 11372283) and the Foundation of Henan Educational Committee, China (Grant No.13A140674).

  17. Mechanical Properties of Polycrystalline Titanium Nitride Films Measured by XRD Tensile Testing

    NASA Astrophysics Data System (ADS)

    Namazu, Takahiro; Inoue, Shozo; Takemoto, Hideki; Koterazawa, Keiji

    This paper describes measurement of mechanical properties of micron-thin polycrystalline titanium nitride (TiN) films. We developed a novel tensile test technique that can directly measure lateral elastic strain of a microscale single/poly-crystalline specimen by means of X-ray diffraction (XRD), which enables evaluation of not only Young's modulus but also Poisson's ratio of TiN films. TiN films having thicknesses of 0.5 μm to 1.6 μm are deposited onto the top and bottom surfaces of a microscale single crystal silicon (Si) specimen. The deposition is carried out by r.f. reactive magnetron sputtering under Ar partial pressure ranging from 0.7 Pa to 1.0 Pa. Average values of Young's modulus and Poisson's ratio for the Si monolayer specimen are found to be 169 GPa and 0.35, respectively, which are in close agreement with analytical values. TiN films deposited under an Ar partial pressure of 0.7 Pa have average Young's modulus of 290 GPa and Poisson's ratio of 0.36. These values gradually decrease with increasing Ar partial pressure, but are independent of TiN film thickness. Fracture strength of a TiN/Si/TiN composite specimen shows dependence on film thickness, regardless of Ar partial pressure.

  18. Effects of strain rate, test temperature and test environment on tensile properties of vandium alloys

    SciTech Connect

    Gubbi, A.N.; Rowcliffe, A.F.; Eatherly, W.S.; Gibson, L.T.

    1996-10-01

    Tensile testing was carried out on SS-3 tensile specimens punched from 0.762-mm-thick sheets of the large heat of V-4Cr-4Ti and small heats of V-3Cr-3Ti and V-6Cr-6Ti. The tensile specimens were annealed at 1000{degrees} for 2 h to obtain a fully recrystallized, fine grain microstructure with a grain size in the range of 10-19 {mu}m. Room temperature tests at strain rates ranging from 10{sup {minus}3} to 5 x 10{sup {minus}1}/s were carried out in air; elevated temperature testing up to 700{degrees}C was conducted in a vacuum better than 1 x 10{sup {minus}5} torr (<10{sup {minus}3} Pa). To study the effect of atomic hydrogen on ductility, tensile tests were conducted at room temperature in an ultra high vacuum chamber (UHV) with a hydrogen leak system.

  19. The development of a tensile-shear punch correlation for yield properties of model austenitic alloys

    SciTech Connect

    Hankin, G.L.; Faulkner, R.G.; Hamilton, M.L.; Garner, F.A.

    1997-08-01

    The effective shear yield and maximum strengths of a set of neutron-irradiated, isotopically tailored austentic alloys were evaluated using the shear punch test. The dependence on composition and neutron dose showed the same trends as were observed in the corresponding miniature tensile specimen study conducted earlier. A single tensile-shear punch correlation was developed for the three alloys in which the maximum shear stress or Tresca criterion was successfully applied to predict the slope. The correlation will predict the tensile yield strength of the three different austenitic alloys tested to within {+-}53 MPa. The accuracy of the correlation improves with increasing material strength, to within {+-} MPa for predicting tensile yield strengths in the range of 400-800 MPa.

  20. Tensile properties of V-Cr-Ti alloys after exposure in helium and low-partial-pressure oxygen environments

    SciTech Connect

    Natesan, K.; Soppet, W.K.

    1997-04-01

    A test program is in progress to evaluate the effect of oxygen at low pO{sub 2} on the tensile properties of V-(4-5)wt% Cr-(4-5)wt% Ti alloys. Some of the tensile specimens were precharged with oxygen at low pO{sub 2} at 500{degrees}C and reannealed in vacuum at 500{degrees}C in environments with various pO{sub 2} levels and subsequently tensile tested at room temperature. The preliminary results indicate that both approaches are appropriate for evaluating the effect of oxygen uptake on the tensile properties of the alloys. The data showed that in the relatively short-time tests conducted thus far, the maximum engineering stress slightly increased after oxygen exposure but the uniform and total elongation values exhibited significant decrease after exposure in oxygen-containing environments. The data for a specimen exposed to a helium environment were similar to those obtained in low pO{sub 2} environments.

  1. Heat Treatment Effects on the Tensile Properties and Microstructures of a SiC/RBSN Composite in Nitrogen

    NASA Technical Reports Server (NTRS)

    Bhatt, R. T.

    1995-01-01

    The room-temperature tensile properties and constituent microstructures of a unidirectionally reinforced SiC/reaction bonded silicon nitride (RBSN) composite have been investigated after heat treatments at 1400, 1600, or 1800 C in nitrogen for up to 100 hr. The composite consisted of approximately 24 vol% of aligned 140 micron diameter, continuous length, chemically vapor deposited SiC fibers in an approximately 40% porous silicon nitride matrix. The composites heat treated at 1400 C for up to 100 hr showed elastic modulus, first matrix cracking strength, and ultimate tensile strength values similar to those of the as-fabricated composites, but those heat treated for 1 hr beyond this temperature displayed losses in all three properties. Recrystallization of the SiC fibers, reaction between the carbon-rich interface coating on the fibers and the RBSN matrix, and dissociation of the RBSN matrix are the reasons for the loss of mechanical properties.

  2. Interaction of Bearing and Tensile Loads on Creep Properties of Joints

    NASA Technical Reports Server (NTRS)

    Bodine, E G; Carlson, R L; Manning, G K

    1956-01-01

    The interaction of bearing and tensile loads on the creep behavior of joints was studied. A specimen was designed for this study which possessed some of the general features of pin and rivet joint connections and an apparatus was constructed to apply both bearing and tensile loads to the joint model. Deformation measurements were made by use of a photogrid printed on the joint model.

  3. A comparison between porcine, ovine, and bovine intervertebral disc anatomy and single lamella annulus fibrosus tensile properties.

    PubMed

    Monaco, Lauren A; DeWitte-Orr, Stephanie J; Gregory, Diane E

    2016-02-01

    This project aimed to compare gross anatomical measures and biomechanical properties of single lamellae from the annulus fibrosus of ovine and porcine lumbar vertebrae, and bovine tail vertebrae. The morphology of the vertebrae of these species differ significantly both from each other and from human, yet how these differences alter biomechanical properties is unknown. Geometric parameters measured in this study included: 1) absolute and relative intervertebral (IVD) and vertebral body height and 2) absolute and relative intervertebral disc (IVD) anterior-posterior (AP) and medial-lateral (ML) widths. Single lamella tensile properties included toe-region stress and stretch ratio, stiffness, and tensile strength. As expected, the bovine tail IVD revealed a more circular shape compared with both the ovine and porcine lumbar IVD. The bovine tail also had the largest IVD to vertebral body height ratio (due to having the highest absolute IVD height). Bovine tail lamellae were also found to be strongest and stiffest (in tension) while ovine lumbar lamellae were weakest and most compliant. Histological analysis revealed the greatest proportion of collagen in the bovine corroborating findings of increased strength and stiffness. The observed differences in anatomical shape, connective tissue composition, and tensile properties need to be considered when choosing an appropriate model for IVD research. PMID:26558749

  4. Enhancing the tensile properties of continuous millimeter-scale carbon nanotube fibers by densification.

    PubMed

    Hill, Frances A; Havel, Timothy F; Hart, A John; Livermore, Carol

    2013-08-14

    This work presents a study of the tensile mechanical properties of millimeter-long fibers comprising carbon nanotubes (CNTs). These CNT fibers are made of aligned, loosely packed parallel networks of CNTs that are grown in and harvested from CNT forests without drawing or spinning. Unlike typical CNT yarn, the present fibers contain a large fraction of CNTs that span the fibers' entire gauge length. The fibers are densified after growth and network formation to study how increasing the degree of interaction among CNTs in a network by various methods influences and limits the mechanical behavior of macroscopic CNT materials, particularly for the case in which the continuity of a large fraction of CNTs across the gauge length prevents failure purely by slip. Densification is carried out using various combinations of capillary-driven densification, mechanical pressure, and twisting. All methods of densification increase the fiber density and modify the nanoscale order of the CNTs. The highest strength and stiffness values (1.8 and 88.7 N tex(-1), respectively) are observed for capillary-densified fibers, whereas the highest toughness values (94 J g(-1)) and maximum reversible energy density (1.35 kJ kg(-1) or 677 kJ m(-3)) are observed for fibers densified by mechanical pressure. The results suggest that the path to higher performance CNT materials may lie not only in the use of continuous and long CNTs but also in controlling their density and nanoscale ordering through modification of the as-grown networks, such as by capillary-driven densification. PMID:23876225

  5. The Tensile Mechanical Properties of Thermomechanically Consolidated Titanium at Different Strain Rates

    NASA Astrophysics Data System (ADS)

    Liang, Cun; Ma, Mingxing; Jia, Mingtu; Raynova, Stiliana; Yan, Jianqiang; Zhang, Deliang

    2015-11-01

    The microstructures, tensile mechanical properties, and fracture behavior of a commercially pure (CP) titanium disk (called PF/Ti disk) and a CP titanium bar (called PE/Ti bar) made by powder compact forging (PCF) and powder compact extrusion (PCE) respectively have been studied. With increasing the strain rate from 10-4 to 10-1 s-1, the yield strength of the PF/Ti disk and PE/Ti bar increased from 708 to 811 MPa and from 672 to 764 MPa, respectively; their UTS increased from 824 to 1009 MPa and from 809 to 926 MPa, respectively, and their elongation to fracture decreased from 21 to 8 pct and from 25 to 17.8 pct, respectively. With a low strain rate of 10-4 s-1, the PF/Ti disk did not show any cavities at unbonded or weakly bonded interparticle boundaries, but the PE/Ti bar showed a small number of cavities with sizes of around 1 μm. With a high strain rate of 10-2 s-1, the PF/Ti disk showed a small number of cavities with sizes in the range of 0.1 to 0.5 μm, while for the PE/Ti bar, the cavities grew into microcracks of up to 20 μm long. The findings suggest that close to 100 pct of consolidation is rapidly achieved by PCF at 1573 K (1300 °C) and PCE at 1523 K (1250 °C), respectively, possibly due to the dissolution of the particle oxide surface films during heating and rapid diffusion bonding between the fresh particle surfaces during PCF and PCE.

  6. Parametric Study on the Tensile Properties of Ni-Based Alloy for a VHTR

    NASA Astrophysics Data System (ADS)

    Kim, Dong-Jin; Jung, Su Jin; Mun, Byung Hak; Kim, Sung Woo; Lim, Yun Soo

    2015-01-01

    A very high-temperature reactor (VHTR) has been studied among generation IV nuclear power plants owing to its many advantages such as high-electric efficiency and massive hydrogen production. The material used for the heat exchanger should sustain structural integrity for its life even though the material is exposed to a harsh environment at 1223 K (950 °C) in an impure helium coolant. Therefore, an enhancement of the material performance at high temperature gives a margin in determining the operating temperature and life time. This work is an effort to find an optimum combination of alloying elements and processing parameters to improve the material performance. The tensile property and microstructure for nickel-based alloys fabricated in a laboratory were evaluated as a function of the heat treatment, cold working, and grain boundary strengthener using a tension test at 1223 K (950 °C), scanning electron microscopy, and transmission electron microscopy. Elongation to rupture was increased by additional heat treatment and cold working, followed by additional heat treatment in the temperature range from 1293 K to 1383 K (1020 °C to 1110 °C) implying that the intergranular carbide contributes to grain boundary strengthening. The temperature at which the grain boundary is improved by carbide decoration was higher for a cold-worked specimen, which was described by the difference in carbide stability and carbide formation kinetics between no cold-worked and cold-worked specimens. Zr and Hf played a scavenging effect of harmful elements causing an increase in ductility.

  7. Correlation Between Microstructures and Tensile Properties of Strain-Based API X60 Pipeline Steels

    NASA Astrophysics Data System (ADS)

    Sung, Hyo Kyung; Lee, Dong Ho; Lee, Sunghak; Kim, Hyoung Seop; Ro, Yunjo; Lee, Chang Sun; Hwang, Byoungchul; Shin, Sang Yong

    2016-03-01

    The correlation between the microstructures and tensile properties of strain-based American Petroleum Institute (API) X60 pipeline steels was investigated. Eight types of strain-based API X60 pipeline steels were fabricated by varying the chemical compositions, such as C, Ni, Cr, and Mo, and the finish cooling temperatures, such as single-phase and dual-phase regions. In the 4N and 5C steels, the volume fractions of bainitic ferrite (BF) and the secondary phases increased with the increasing C and adding Cr instead of Ni. In the 5C and 6NC steels, the volume fractions of acicular ferrite (AF) and BF decreased with increasing C and adding Ni, whereas the volume fractions of polygonal ferrite (PF) and the secondary phases increased. In the 6NC and 6NM steels, the volume fraction of BF was increased by adding Mo instead of Cr, whereas the volume fractions of PF and the secondary phases decreased. In the steels rolled in the single-phase region, the volume fraction of polygonal ferrite ranged from 40 to 60 pct and the volume fraction of AF ranged from 20 to 40 pct. In the steels rolled in the dual-phase region, however, the volume fraction of PF was more than 70 pct and the volume fraction of AF was below 20 pct. The strength of the steels with a high volume fraction of AF was higher than those of the steels with a high volume fraction of PF, whereas the yield point elongation and the strain hardening exponent were opposite. The uniform elongation after the thermal aging process decreased with increasing volume fraction of PF, whereas the uniform elongation increased with increasing volume fraction of AF. The strain hardening exponent increased with increasing volume fraction of PF, but decreased with increasing volume fraction of AF and effective grain size.

  8. Correlation Between Microstructures and Tensile Properties of Strain-Based API X60 Pipeline Steels

    NASA Astrophysics Data System (ADS)

    Sung, Hyo Kyung; Lee, Dong Ho; Lee, Sunghak; Kim, Hyoung Seop; Ro, Yunjo; Lee, Chang Sun; Hwang, Byoungchul; Shin, Sang Yong

    2016-06-01

    The correlation between the microstructures and tensile properties of strain-based American Petroleum Institute (API) X60 pipeline steels was investigated. Eight types of strain-based API X60 pipeline steels were fabricated by varying the chemical compositions, such as C, Ni, Cr, and Mo, and the finish cooling temperatures, such as single-phase and dual-phase regions. In the 4N and 5C steels, the volume fractions of bainitic ferrite (BF) and the secondary phases increased with the increasing C and adding Cr instead of Ni. In the 5C and 6NC steels, the volume fractions of acicular ferrite (AF) and BF decreased with increasing C and adding Ni, whereas the volume fractions of polygonal ferrite (PF) and the secondary phases increased. In the 6NC and 6NM steels, the volume fraction of BF was increased by adding Mo instead of Cr, whereas the volume fractions of PF and the secondary phases decreased. In the steels rolled in the single-phase region, the volume fraction of polygonal ferrite ranged from 40 to 60 pct and the volume fraction of AF ranged from 20 to 40 pct. In the steels rolled in the dual-phase region, however, the volume fraction of PF was more than 70 pct and the volume fraction of AF was below 20 pct. The strength of the steels with a high volume fraction of AF was higher than those of the steels with a high volume fraction of PF, whereas the yield point elongation and the strain hardening exponent were opposite. The uniform elongation after the thermal aging process decreased with increasing volume fraction of PF, whereas the uniform elongation increased with increasing volume fraction of AF. The strain hardening exponent increased with increasing volume fraction of PF, but decreased with increasing volume fraction of AF and effective grain size.

  9. Corrosion Embrittlement of Duralumin VI The Effect of Corrosion Accompanied by Stress on the Tensile Properties of Sheet Duralumin

    NASA Technical Reports Server (NTRS)

    Rawdon, Henry S

    1929-01-01

    The effect of corrosion on the tensile properties of duralumin while stressed is shown in graphical form. According to the test results, duralumin sheet, coated with aluminum, maintains its initial properties unimpaired for corrosion periods as long as 60 days with an applied tensile stress as high as 20,000 lb/sq.in., which is approximately one-half the stress corresponding to the yield point as defined here. In these tests, that material which had been heat-treated by being quenched in cold water, though far inferior to similar material having the aluminum coating, was superior to the sheet material which was heat treated by being quenched in hot water. These results are in excellent agreement with the results of previous laboratory and exposure tests.

  10. Effect of Ultrasonic Treatment on The Tensile and Impact Properties of Thermoplastic Natural Rubber Nanocomposites Reinforced with Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Tarawneh, Mou'ad A.; Ahmad, Sahrim Hj.; Yahya, S. Y.; Rasid, Rozaidi

    2009-06-01

    This study investigates the effect of ultrasonic treatment on the mechanical properties of thermoplastic natural rubber (TPNR) nanocomposites reinforced with multi-walled nanotubes. The TPNR nanocomposites were prepared using melt blending method from polypropylene (PP), natural rubber (NR) and liquid natural rubber (LNR) as a compatibilizer, respectively, with 1% of Multi-wall nanotubes. The nanocomposite was prepared using the indirect technique (IDT) with the optimum processing parameters at 180° C with 80 rpm mixing speed and 11 minutes processing time. The results have showed that the good dispersion on nanotubes was achieved by ultrasonic treatment. The optimization of ultrasonic time indicated that the maximum tensile and impact properties occurred with 1 h ultrasonic treatment. The Young's modulus, tensile strength, elongation at break and impact strength have increased by almost 11%, 21%, 43% and 50%, respectively. The results from our study indicate that nanotubes have as excellent reinforcement filler in TPNR matrix.

  11. Effect of Ultrasonic Treatment on The Tensile and Impact Properties of Thermoplastic Natural Rubber Nanocomposites Reinforced with Carbon Nanotubes

    SciTech Connect

    Tarawneh, Mou'ad A.; Ahmad, Sahrim Hj.; Rasid, Rozaidi; Yahya, S. Y.

    2009-06-01

    This study investigates the effect of ultrasonic treatment on the mechanical properties of thermoplastic natural rubber (TPNR) nanocomposites reinforced with multi-walled nanotubes. The TPNR nanocomposites were prepared using melt blending method from polypropylene (PP), natural rubber (NR) and liquid natural rubber (LNR) as a compatibilizer, respectively, with 1% of Multi-wall nanotubes. The nanocomposite was prepared using the indirect technique (IDT) with the optimum processing parameters at 180 deg. C with 80 rpm mixing speed and 11 minutes processing time. The results have showed that the good dispersion on nanotubes was achieved by ultrasonic treatment. The optimization of ultrasonic time indicated that the maximum tensile and impact properties occurred with 1 h ultrasonic treatment. The Young's modulus, tensile strength, elongation at break and impact strength have increased by almost 11%, 21%, 43% and 50%, respectively. The results from our study indicate that nanotubes have as excellent reinforcement filler in TPNR matrix.

  12. Finite Element Analysis of Deformation Due to Ball Indentation and Evaluation of Tensile Properties of Tempered P92 Steel

    NASA Astrophysics Data System (ADS)

    Barbadikar, Dipika R.; Ballal, A. R.; Peshwe, D. R.; Mathew, M. D.

    2015-08-01

    Ball indentation (BI) technique has been effectively used to evaluate the tensile properties with minimal volume of material. In the present investigation, BI test carried out on P92 steel (9Cr-0.5Mo-1.8W), using 0.76 mm diameter silicon nitride ball indenter was modeled using finite element (FE) method and analyzed. The effect of test temperature [300 K and 923 K (27 °C and 650 °C)], tempering temperature [1013 K, 1033 K, and 1053 K (740 °C, 760 °C, and 780 °C)], and coefficient of friction of steel (0.0 to 0.5) on the tensile strength and material pile-up was investigated. The stress and strain distributions underneath the indenter and along the top elements of the model have been studied to understand the deformation behavior. The tensile strength was found to decrease with increase in tempering and test temperatures. The increased pile-up around the indentation was attributed to the decrease in strain hardening exponent ( n) with increase in the test temperature. The pile-up height determined from profilometry studies and FE analysis as well as the load depth curve from BI and FE analysis was in agreement. The maximum strain location below the indentation changes with the test temperature. Stress-strain curves obtained by conventional tensile, BI test, and representative stress-strain concepts of FE model were found exactly matching.

  13. Subtask 12G2: Effects of dynamically charged helium on tensile properties of V-4Cr-4Ti

    SciTech Connect

    Chung, H.M.; Loomis, B.A.; Nowicki, L.; Smith, D.L.

    1995-03-01

    The objective of this work is to determine the effect of displacement damage and dynamically charged helium on tensile properties of V-4Cr-4Ti alloy irradiated to 18-31 dpa at 425-600{degrees}C in the Dynamic Helium Charging Experiment (DHCE). One property of vanadium-base alloys that is not well understood in terms of their potential use as fusion reactor structural materials is the effect of simultaneous generation of helium and neutron damage under conditions relevant to fusion reactor operation. In the present Dynamic Helium Charging Experiment (DHCE), helium was produced uniformly in the specimen at linear rates of {approx}0.4 to 4.2 appm helium/dpa by the decay of tritium during irradiation to 18-31 dpa at 425-600{degrees}C in the Li-filled DHCE capsules in the Fast Flux Test Facility. This report presents results of postirradiation tests of tensile properties of V-4Cr-4Ti, an alloy identified as the most promising vanadium-base alloy for fusion reactors on the basis of its superior baseline and irradiation properties. Effects of helium on tensile strength and ductility were insignificant after irradiation and testing at >420{degrees}C. Contrary to initial expectation, room-temperature ductilities of DHCE specimens were higher than those of non-DHCE specimens (in which there was negligible helium generation), whereas strengths were lower, indicating that different types of hardening centers are produced during DHCE and non-DHCE irradiation. In strong contrast to tritium-trick experiments in which dense coalescence of helium bubbles is produced on grain boundaries in the absence of displacement damage, no intergranular fracture was observed in any tensile specimens irradiated in the DHCE. 25 refs., 2 figs., 3 tabs.

  14. Tensile properties of V-5Cr-5Ti alloy after exposure in air environment

    SciTech Connect

    Natesan, K.; Soppet, W.K.

    1997-04-01

    Oxidation studies were conducted on V-5Cr-5Ti alloy specimens in an air environment to evaluate the oxygen uptake behavior of the alloy as a function of temperature and exposure time. The oxidation rates, calculated from parabolic kinetic measurements of thermogravimetric testing and confirmed by microscopic analysis of cross sections of exposed specimens, were 5, 17, and 27 {mu}m per year after exposure at 300, 400, and 500{degrees}C, respectively. Uniaxial tensile tests were conducted at room temperature and at 500{degrees}C on preoxidized specimens of the alloy to examine the effects of oxidation and oxygen migration on tensile strength and ductility. Correlations were developed between tensile strength and ductility of the oxidized alloy and microstructural characteristics such as oxide thickness, depth of hardened layer, depth of intergranular fracture zone, and transverse crack length.

  15. High-temperature Tensile Properties and Creep Life Assessment of 25Cr35NiNb Micro-alloyed Steel

    NASA Astrophysics Data System (ADS)

    Ghatak, Amitava; Robi, P. S.

    2016-05-01

    Reformer tubes in petrochemical industries are exposed to high temperatures and gas pressure for prolonged period. Exposure of these tubes at severe operating conditions results in change in the microstructure and degradation of mechanical properties which may lead to premature failure. The present work highlights the high-temperature tensile properties and remaining creep life prediction using Larson-Miller parametric technique of service exposed 25Cr35NiNb micro-alloyed reformer tube. Young's modulus, yield strength, and ultimate tensile strength of the steel are lower than the virgin material and decreases with the increase in temperature. Ductility continuously increases with the increase in temperature up to 1000 °C. Strain hardening exponent increases up to 600 °C, beyond which it starts decreasing. The tensile properties are discussed with reference to microstructure and fractographs. Based on Larson-Miller technique, a creep life of at least 8.3 years is predicted for the service exposed material at 800 °C and 5 MPa.

  16. Effect of heat treatments on the tensile and electrical properties of high-strength, high-conductivity copper alloys

    SciTech Connect

    Zinkle, S.J.; Eatherly, W.S.

    1997-08-01

    The unirradiated tensile properties of CuCrZr produced by two different vendors have been measured following different heat treatments. Room temperature electrical resistivity measurements were also performed in order to estimate the thermal conductivity of these specimens. The thermomechanical conditions studied included solution quenched, solution quenched and aged (ITER reference heat treatment), simulated slow HIP thermal cycle ({approximately}1{degrees}C/min cooling from solutionizing temperature) and simulated fast HIP thermal cycle ({approximately}100{degrees}C/min cooling from solutionizing temperature). Specimens from the last two heat treatments were tested in both the solution-cooled condition and after subsequent precipitate aging at 475{degrees}C for 2 h. Both of the simulated HIP thermal cycles caused a pronounced decreases in the strength and electrical conductivity of CuCrZr. The tensile and electrical properties were unchanged by subsequent aging in the slow HIP thermal cycles caused a pronounced decrease in the strength and electrical conductivity of CuCrZr. The tensile and electrical properties were unchanged by subsequent aging in the slow HIP thermal cycle specimens, whereas the strength and conductivity following aging in the fast HIP thermal cycle improved to {approximately}65% of the solution quenched and aged CuCrZr values. Limited tensile and electrical resistivity measurements were also made on two new heats of Hycon 3HP CuNiBe. High strength but poor uniform and total elongations were observed at 500{degrees}C on one of these new heats of CuNiBe, similar to that observed in other heats.

  17. Tensile properties of explosively formed 316L(N)-IG stainless steel with and without an electron beam weld

    NASA Astrophysics Data System (ADS)

    Hegeman, J. B. J.; Luzginova, N. V.; Jong, M.; Groeneveld, H. D.; Borsboom, A.; Stuivinga, M. E. C.; van der Laan, J. G.

    2011-10-01

    The mechanical properties of two explosively formed saddle shaped 60 mm thick plates of 316L(N)-IG steel with and without an electron beam weld have been investigated. Two different conditions have been characterized: (1) Reference condition and (2) ITER relevant condition. The reference material exhibits consistent results for both plates, mechanical properties of reference material are similar to the properties previously observed for 316L(N)-IG steels. No significant difference in mechanical properties and microstructure between different positions in the 60 mm plate is observed. Tensile properties for ITER relevant materials are found to comply both with the RCC-MR code qualified data for 316L(N) steel used for the structural design and with ITER Materials Properties Handbook. As expected total elongation and uniform elongation for weld material are lower than the average curves obtained for the base material.

  18. Alaskan Fish Gelatin Films: Thermal, Tensile, and Barrier Properties and Effects of Cross-linking

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gelatin was extracted from the skins of Alaska pollock (Theragra chalcogramma) and Alaska pink salmon (Oncorhynchus gorbuscha). These skins were by-products generated from the Alaskan fishing industry. Films were then cast from the fish gelatin and their thermal, tensile, water vapor permeability, o...

  19. Tensile and charpy impact properties of irradiated reduced-activation ferritic steels

    SciTech Connect

    Klueh, R.L.; Alexander, D.J.

    1996-10-01

    Tensile tests were conducted on eight reduced-activation Cr-W steels after irradiation to 15-17 and 26-29 dpa, and Charpy impact tests were conducted on the steels irradiated to 26-29 dpa. Irradiation was in the Fast Flux Test Facility at 365{degrees}C on steels containing 2.25-12% Cr, varying amounts of W, V, and Ta, and 0.1%C. Previously, tensile specimens were irradiated to 6-8 dpa and Charpy specimens to 6-8, 15-17, and 20-24 dpa. Tensile and Charpy specimens were also thermally aged to 20000 h at 365{degrees}C. Thermal aging had little effect on the tensile behavior or the ductile-brittle transition temperature (DBTT), but several steels showed a slight increase in the upper-shelf energy (USE). After {approx}7 dpa, the strength of the steels increased and then remained relatively unchanged through 26-29 dpa (i.e., the strength saturated with fluence). Post-irradiation Charpy impact tests after 26-29 dpa showed that the loss of impact toughness, as measured by an increase in DBTT and a decrease in the USE, remained relatively unchanged from the values after 20-24 dpa, which had been relatively unchanged from the earlier irradiations. As before, the two 9Cr steels were the most irradiation resistant.

  20. Tensile properties of glass/natural jute fibre-reinforced polymer bars for concrete reinforcement

    NASA Astrophysics Data System (ADS)

    Han, J. W.; Lee, S. K.; Kim, K. W.; Park, C. G.

    2015-12-01

    The tensile performance of glass/natural jute fibre-reinforced polymer (FRP) bar, intended for concrete reinforcement was evaluated as a function of volume fraction of natural jute fibre. Natural jute fibre, mixed at a ratio of 7:3 with vinyl ester, was surface-treated with a silane coupling agent and used to replaced glass fibre in the composite in volume fractions of 0%, 30%, 50%, 70%, and 100%. The tensile load-displacement curve showed nearly linear elastic behaviour up to 50% natural jute fibre, but was partially nonlinear at a proportion of 70%. However, the glass/natural jute FRP bars prepared using 100% natural jute fibre showed linear elastic behaviour. Tensile strength decreased as the natural jute fibre volume fraction increased because the tensile strength of natural jute fibre is much lower than that of glass fibre (about 1:8.65). The degree of reduction was not proportional to the natural jute fibre volume fraction due to the low density of natural jute fibre (1/2 that of glass fibre). Thus, as the mix proportion of natural jute fibre increased, the amount (wt%) and number of fibres used also increased.

  1. Improving the creep resistance and tensile property of UHMWPE sheet by radiation cross-linking and annealing

    NASA Astrophysics Data System (ADS)

    Wang, Honglong; Xu, Lu; Li, Rong; Hu, Jiangtao; Wang, Mouhua; Wu, Guozhong

    2016-08-01

    Ultra-high molecular weight polyethylene (UHMWPE) sheet was cross-linked by γ irradiation in air with a dose of up to 300 kGy at a dose rate of 5 kGy/h and further treated by post-annealing at 120 °C for 4 h in vacuum. Variations in chemical structure, thermostability, crystallinity, creep resistance, and tensile properties were investigated and compared mainly by gel content, TGA, DSC, and creep and tensile measurements. Gel content measurements indicated that cross-linking was predominant over chain scission during irradiation and post-annealing. Radiation cross-linking resulted in an obvious improvement in the creep resistance and tensile properties of UHMWPE. Through cross-linking, the operational temperature and yield strength of the irradiated and subsequently annealed UHMWPE sheet were improved by more than 100 °C and 14%, respectively, at a dose of 300 kGy. Simultaneously, Young's modulus was increased to 1413 MPa, compared with 398 MPa of pristine UHMWPE. Annealing after irradiation further improved the creep resistance and Young's modulus. Highly cross-linked UHMWPE can even be maintained at 250 °C for a long time without any obvious deformation.

  2. Tensile properties and translaminar fracture toughness of glass fiber reinforced unsaturated polyester resin composites aged in distilled and salt water

    NASA Astrophysics Data System (ADS)

    Sugiman, Gozali, M. Hulaifi; Setyawan, Paryanto Dwi

    2016-03-01

    Glass fiber reinforced polymer has been widely used in chemical industry and transportation due to lightweight and cost effective manufacturing. However due to the ability to absorb water from the environment, the durability issue is of interest for up to days. This paper investigated the water uptake and the effect of absorbed water on the tensile properties and the translaminar fracture toughness of glass fiber reinforced unsaturated polyester composites (GFRP) aged in distilled and salt water up to 30 days at a temperature of 50°C. It has been shown that GFRP absorbed more water in distilled water than in salt water. In distilled water, the tensile strength of GFRP tends to decrease steeply at 7 days and then slightly recovered for further immersion time. In salt water, the tensile strength tends to decrease continually up to 30 days immersion. The translaminar fracture toughness of GFRP aged in both distilled and salt-water shows the similar behavior. The translaminar fracture toughness increases after 7 days immersion and then tends to decrease beyond that immersion time. In the existence of ionics content in salt water, it causes more detrimental effect on the mechanical properties of fiberglass/unsaturated polyester composites compared to that of distilled water.

  3. Tensile and electrical properties of unirradiated and irradiated Hycon 3HP{trademark} CuNiBe

    SciTech Connect

    Zinkle, S.J.; Eatherly, W.S.

    1996-10-01

    The unirradiated tensile properties of two different heats of Hycon 3HP{trademark} CuNiBe (HT Temper) have been measured over the temperature range of 20-500{degrees}C for longitudinal and long transverse orientations. The room temperature electrical conductivity has also been measured for both heats. Both heats exhibited a very good combination of strength and conductivity at room temperature. The strength remained relatively high at all test temperatures, with a yield strength of 420-520 MPa at 500{degrees}C. However, low levels of ductility (<5% uniform elongation) were observed at test temperatures above 200-250{degrees}C, due to flow localization adjacent to grain boundaries. Fission neutron irradiation to a dose of {approximately}0.7 dpa at temperatures between 100 and 240{degrees}C produced a slight increase in strength and a significant decrease in ductility. The measured tensile elongation increased with increasing irradiation temperature, with a uniform elongation of {approximately}3.3% observed at 240{degrees}C. The electrical conductivity decreased slightly following irradiation, due to the presence of defect clusters and Ni, Zn, Co transmutation products. The data indicate that CuNiBe alloys have irradiated tensile and electrical properties comparable or superior to CuCrZr and oxide dispersion strengthened copper at temperatures <250{degrees}C, and may be suitable for certain fusion energy structural applications.

  4. Influence of repair welding of aged 18Ni 250 maraging steel weldments on tensile and fracture properties

    SciTech Connect

    Sinha, P.P.; Arumugham, S.; Nagarajan, K.V. . Materials and Metallurgy Group)

    1993-08-01

    The effects of repair welding on tensile strength and fracture toughness of aged weldments of 18 Ni 250-grade maraging steel have been studied. It has been established that aged weldments in the steel can be repaired and approximately 95% of the tensile strength of the initial welds could be achieved by postrepair aging treatment. Also, the repairs had practically no effect on the fracture toughness (K[sub IC]) of the weldment. These results have been discussed in terms of microstructural conditions in the various affected and unaffected zones of the initial weld. One important inference that emerges from the mechanical properties-microstructural correlation in the study is that (K[sub IC]) of the weld is independent of the gross microstructural features of the dendritic size and shapes in the ranges observed in this study. It has, however, been cautioned that the above statement is not valid in cases in which heavy segregation occurs along the interdendritic boundaries resulting in heavily banded microstructure. This can result from faulty weld parameters such as excessive heat input. A second aging to recover the mechanical properties of the repaired zone has additional beneficial effects on tensile strengths and helps in maintaining fracture toughness to the original level of the initial weld.

  5. Effect of copper-rich regions on tensile properties of VPPA weldments of 2219-T87 aluminum

    NASA Technical Reports Server (NTRS)

    Hartman, J. A.; Beil, R. J.; Hahn, G. T.

    1987-01-01

    This study examines the relations between tensile properties and microstructural features of variable polarity plasma arc (VPPA) weldments of 2219-T87 aluminum. Crack initiation and weld failure of transverse tensile specimens of single and multipass weldments were studied. The specimens fractured on the rising portion of the stress-strain curve prior to necking, signifying that an increase in strength would accompany an increase in ductility. Of particular interest is a shallow, typically 0.001-0.003-in. (0.03-0.08-mm) deep, copper-rich region located in the crown and root corners of the weld. This region is a primary source of crack initiation and growth, due to its brittle nature and highly strained location. The brittle regions were removed by electropolishing and machining to determine their effect on weld tensile properties. The removal increased the ductility of the weld specimens, and in the case of single pass welds, actually increased the load carrying capacity. Local strain measurements and metallographic and chemical analyses are presented.

  6. Heat treatment effects on tensile properties of V-(4-5) wt.% Cr-(4-5) wt.% Ti alloys

    SciTech Connect

    Natesan, K.; Soppet, W.K.

    1997-08-01

    Effects of thermomechanical treatments on microstructures and mechanical properties are of interest for long term application of V-Cr-Ti alloys in fusion reactor systems. Influence of thermal annealing at 1050{degrees}C on stress/strain behavior, maximum engineering strength, and uniform and total elongation were evaluated. The results show that multiple annealing has minimal effect on the tensile properties of V-(4-5)Cr-(4-5)Ti alloys tested at room temperature and at 500{degrees}C.

  7. Effect of rolling on the high temperature tensile and stress-rupture properties of tungsten fiber-superalloy composites

    NASA Technical Reports Server (NTRS)

    Petrasek, D. W.

    1974-01-01

    An investigation was conducted to determine the effects of mechanical working on the 1093 C tensile and stress-rupture strength of tungsten alloy/superalloy composites. Hot pressed composites containing either conventional tungsten lamp filament wire or tungsten-1% ThO2 wire and a nickel base alloy matrix were hot rolled at 1093 C. The hot pressed and rolled composite specimens were then tested in tension and stress-rupture at 1093 C. Rolling decreased the degree of fiber-matrix reaction as a function of time of exposure at 1093 C. The stress-rupture properties of the rolled composites were superior to hot pressed composites containing equivalent diameter fibers. Rolling did not appreciably affect the 1093 C ultimate tensile strength of the composites.

  8. Effect of rolling on the high temperature tensile and stress-rupture properties of tungsten fiber-superalloy composites

    NASA Technical Reports Server (NTRS)

    Petrasek, D. W.

    1974-01-01

    An investigation was conducted to determine the effects of mechanical working on the 1093 C (2000 F) tensile and stress-rupture strength of tungsten alloy/superalloy composites. Hot pressed composites containing either conventional tungsten lamp filament wire or tungsten-1% ThO2 wire and a nickel base alloy matrix were hot rolled at 1093 C (2000 F). The hot pressed and rolled composite specimens were then tested in tension and stress-rupture at 1093 C (2000 F). Rolling decreased the degree of fiber-matrix reaction as a function of time of exposure at 1093 C (2000 F). The stress-rupture properties of the rolled composites were superior to hot pressed composites containing equivalent diameter fibers. Rolling did not appreciably affect the 1093 C (2000 F) ultimate tensile strength of the composites.

  9. Tensile property of a hot work tool steel prepared by biomimetic coupled laser remelting process with different laser input energies

    NASA Astrophysics Data System (ADS)

    Wang, Chuanwei; Zhou, Hong; Zhang, Zhihui; Zhao, Yu; Zhang, Peng; Cong, Dalong; Meng, Chao; Tan, Fuxing

    2012-09-01

    Coupled with the biomimetic principle, a hot work tool steel (4Cr5MoSiV1) was manufactured using a laser with different input energies. Results of tensile tests confirmed that the biomimetic coupled laser remelting (BCLR) process had an advance effect on improving the strength and ductility of 4Cr5MoSiV1 steel simultaneously. Microstructure examinations demonstrated that a fine microstructure along with nano scale carbide was acquired in the BCLR units, which produced an accumulative contribution of grain refinement, precipitation strengthening and a mixed microstructure. Based on the well distribution of the BCLR units, the beneficial effect of stress transfer from the matrix to the units on tensile property was also analyzed.

  10. Tensile flow properties of Al-based matrix composites reinforced with a random planar network of continuous metallic fibers

    SciTech Connect

    Boland, F.; Salmon, C.; Delannay, F.; Colin, C.

    1998-11-20

    Squeeze casting was used for processing two new types of composites: pure Al matrix composites reinforced with fibers of Inconel 601, and AS13 (Al-12% Si) matrix composites reinforced with fibers of Inconel 601 or stainless steel 316L. The fibers are continuous with a diameter of 12 {micro}m and their volume fraction in the composites varied from 20 to 80%. The processing conditions were such that no trace of interfacial reaction compound or of matrix precipitate resulting from the dissolution of elements of the fibers could be detected. The quality of the process was attested by Young`s modulus and electrical conductivity measurements. Tensile tests were carried out from room temperature up to 300 C. The composites with the pure Al matrix present a remarkable tensile ductility. They thus constitute convenient materials for assessing continuum plasticity models for composites. Properties of composites with the AS13 matrix are much affected by interface adhesion strength.

  11. Effects of helium implantation on the tensile properties and microstructure of Ni₇₃P₂₇ metallic glass nanostructures

    DOE PAGESBeta

    Liontas, Rachel; Gu, X. Wendy; Fu, Engang; Wang, Yongqiang; Li, Nan; Mara, Nathan; Greer, Julia R.

    2014-09-10

    We report fabrication and nanomechanical tension experiments on as-fabricated and helium-implanted ~130 nm diameter Ni₇₃P₂₇ metallic glass nano-cylinders. The nano-cylinders were fabricated by a templated electroplating process and implanted with He⁺ at energies of 50, 100, 150, and 200 keV to create a uniform helium concentration of ~3 at. % throughout the nano-cylinders. Transmission electron microscopy (TEM) imaging and through-focus analysis reveal that the specimens contained ~2 nm helium bubbles distributed uniformly throughout the nano-cylinder volume. In-situ tensile experiments indicate that helium-implanted specimens exhibit enhanced ductility as evidenced by a 2-fold increase in plastic strain over as-fabricated specimens, with nomore » sacrifice in yield and ultimate tensile strengths. This improvement in mechanical properties suggests that metallic glasses may actually exhibit a favorable response to high levels of helium implantation.« less

  12. Effects of helium implantation on the tensile properties and microstructure of Ni₇₃P₂₇ metallic glass nanostructures

    SciTech Connect

    Liontas, Rachel; Gu, X. Wendy; Fu, Engang; Wang, Yongqiang; Li, Nan; Mara, Nathan; Greer, Julia R.

    2014-09-10

    We report fabrication and nanomechanical tension experiments on as-fabricated and helium-implanted ~130 nm diameter Ni₇₃P₂₇ metallic glass nano-cylinders. The nano-cylinders were fabricated by a templated electroplating process and implanted with He⁺ at energies of 50, 100, 150, and 200 keV to create a uniform helium concentration of ~3 at. % throughout the nano-cylinders. Transmission electron microscopy (TEM) imaging and through-focus analysis reveal that the specimens contained ~2 nm helium bubbles distributed uniformly throughout the nano-cylinder volume. In-situ tensile experiments indicate that helium-implanted specimens exhibit enhanced ductility as evidenced by a 2-fold increase in plastic strain over as-fabricated specimens, with no sacrifice in yield and ultimate tensile strengths. This improvement in mechanical properties suggests that metallic glasses may actually exhibit a favorable response to high levels of helium implantation.

  13. Tensile properties of V-(4-15)Cr-5Ti alloys irradiated at 400{degrees}C in the HFIR

    SciTech Connect

    Chung, H.M.; Nowicki, L.; Smith, D.L.

    1996-10-01

    V-(4-15)Cr-5Ti alloys were irradiated in a helium environment to {approx}10 dpa at {approx}400{degrees}C in the High Flux Isotope Reactor (HFIR). This report presents results of postirradiation tests of tensile properties of V-4Cr-4Ti, V-8Cr-6Ti, V-10Cr-5Ti, and V-15Cr-5Ti. Despite concerns on the effects of transmutation of vanadium to Cr and impurity pickup from the helium environment, all of the alloys exhibited ductile tensile behavior. However, the alloys exhibited ductilities somewhat lower than those of the specimens irradiated to a similar dose and at a similar temperature in an Li environment in fast reactors. Uniform plastic strain in the V-Cr-(4-5)Ti alloys decreased monotonically with increasing Cr content.

  14. Effects of helium implantation on the tensile properties and microstructure of Ni73P27 metallic glass nanostructures.

    PubMed

    Liontas, Rachel; Gu, X Wendy; Fu, Engang; Wang, Yongqiang; Li, Nan; Mara, Nathan; Greer, Julia R

    2014-09-10

    We report fabrication and nanomechanical tension experiments on as-fabricated and helium-implanted ∼130 nm diameter Ni73P27 metallic glass nanocylinders. The nanocylinders were fabricated by a templated electroplating process and implanted with He(+) at energies of 50, 100, 150, and 200 keV to create a uniform helium concentration of ∼3 atom % throughout the nanocylinders. Transmission electron microscopy imaging and through-focus analysis reveal that the specimens contained ∼2 nm helium bubbles distributed uniformly throughout the nanocylinder volume. In situ tensile experiments indicate that helium-implanted specimens exhibit enhanced ductility as evidenced by a 2-fold increase in plastic strain over as-fabricated specimens with no sacrifice in yield and ultimate tensile strengths. This improvement in mechanical properties suggests that metallic glasses may actually exhibit a favorable response to high levels of helium implantation. PMID:25084487

  15. Effects of material properties and speed of compression on microbial survival and tensile strength in diclofenac tablet formulations.

    PubMed

    Ayorinde, J O; Itiola, O A; Odeniyi, M A

    2013-03-01

    A work has been done to study the effects of material properties and compression speed on microbial survival and tensile strength in diclofenac tablet formulations. Tablets were produced from three formulations containing diclofenac and different excipients (DC, DL and DDCP). Two types of machines (Hydraulic hand press and single punch press), which compress the tablets at different speeds, were used. The compression properties of the tablets were analyzed using Heckel and Kawakita equations. A 3-dimensional plot was produced to determine the relationship between the tensile strength, compression speed and percentage survival of Bacillus subtilis in the diclofenac tablets. The mode of consolidation of diclofenac was found to depends on the excipient used in the formulation. DC deformed mainly by plastic flow with the lowest Py and Pk values. DL deformed plastically at the initial stage, followed by fragmentation at the later stage of compression, whereas DDCP deformed mainly by fragmentation with the highest Py and Pk values. The ranking of the percentage survival of B. subtilis in the formulations was DDCP > DL > DC, whereas the ranking of the tensile strength of the tablets was DDCP > DL > DC. Tablets produced on a hydraulic hand press with a lower compression speed had a lower percentage survival of microbial contaminants than those produced on a single punch press, which compressed the tablets at a much higher speed. The mode of consolidation of the materials and the speed at which tablet compression is carried out have effects on both the tensile strength of the tablets and the extent of destruction of microbial contaminants in diclofenac tablet formulations. PMID:23471558

  16. Effect of service usage on tensile, fatigue, and fracture properties of 7075-T6 and 7178-T6 aluminum alloys

    NASA Technical Reports Server (NTRS)

    Everett, R. A., Jr.

    1975-01-01

    A study has been made to determine the effects of extensive service usage on some basic material properties of 7075-T6 and 7178-T6 aluminum alloy materials. The effects of service usage were determined by comparing material properties for new material (generally obtained from the literature) with those for material cut from the center wing box of a C-130B transport airplane with 6385 flight-hours of service. The properties investigated were notched and unnotched fatigue strengths, fatigue-crack-growth rate, fracture toughness, and tensile properties. For the properties investigated and the parameter ranges considered (crack length, stress ratio, etc.), the results obtained showed no significant difference between service and new materials.

  17. Effect of tool velocity ratio on tensile properties of friction stir processed aluminum based metal matrix composites

    NASA Astrophysics Data System (ADS)

    Vijayavel, P.; Balasubramanian, V.

    2016-08-01

    In friction stir processing (FSP), tool rotational speed (TRS) and tool traverse speed (TTS) are the two important parameters, known to produce significant changes in the properties of the processed material. Increasing the TRS and TTS beyond a certain level would produce undesirable results. The heat generation will increase with an increase in the TRS and decrease in TTS. Excessive heat generation results in the formation of coarse grains exhibiting poor mechanical properties. The heat generation will decrease with decrease in the TRS and increase in TTS. Low heat generation will lead to inadequate plasticization and improper material flow. Hence a perfect combination of TRS and TTS is required to attain desirable properties in FSPed material. In this investigation FSP was carried out on aluminum based metal matrix composite (LM25AA+5%SiCp) material using five different tool velocity ratios (TVR: TRS/TTS). The FSP was subjected to microstructural characterization and tensile properties, evaluation. The results revealed that the TVR of 2.6 yielded superior tensile properties compared to other conditions.

  18. Effects of postmortem freezing on tensile failure properties of rabbit extensor digitorum longus muscle tendon complex.

    PubMed

    Leitschuh, P H; Doherty, T J; Taylor, D C; Brooks, D E; Ryan, J B

    1996-09-01

    The tensile failures of extensor digitorum longus muscle tendon units from 16 male New Zealand White rabbits were studied in the fresh state (less than 30 minutes after death) and in the frozen/thawed state (frozen at -80 degrees C for 28 days and then warmed to 38 degrees C). Frozen/thawed extensor digitorum longus muscle tendon units had significantly lower values for load to failure (p < 0.01), energy absorbed to failure (p < 0.01), and strain at failure (p < 0.01), and they tended to fail at a different anatomic location (p < 0.01) (broadly at the fascia-muscle interface as compared with horizontally at the musculotendinous junction) than fresh units. The results of this study suggest that freezing muscle tendon units significantly alters their tensile failure characteristics. PMID:8893779

  19. Tensile and characterization properties of regenerated cellulose empty fruit bunch biocomposite films using ionic liquid

    NASA Astrophysics Data System (ADS)

    Husseinsyah, Salmah; Zailuddin, Nur Liyana Izyan; Li, Chew Li; Mostapha @ Zakaria, Marliza

    2016-07-01

    The regenerated cellulose (RC) empty fruit bunch (EFB) biocomposite films were prepared using ionic liquid. The tensile strength and modulus of elasticity of regenerated cellulose biocomposite films achieved maximum value at 2 wt% of EFB contents while at 3 and 4 wt% of EFB the tensile strength and modulus of elasticity tend to decreased. The elongation at break tends to decreased at 2 wt% of EFB content but increased at 3 and 4 wt% of EFB contents. The crystallinity index reaches maximum at 2 wt% EFB content, followed by declination with further addition of EFB content. The morphology study illustrated that regenerated cellulose biocomposite films at 2 wt% of EFB contents exhibit a smooth surface that suggested the reinforcement was surrounded by the regenerated cellulose matrix, while at 4 wt% EFB content shows a rough morphology.

  20. Tensile properties of CLAM steel irradiated up to 20.1 dpa in STIP-V

    NASA Astrophysics Data System (ADS)

    Ge, Hongen; Peng, Lei; Dai, Yong; Huang, Qunying; Ye, Minyou

    2016-01-01

    Specimens of China low activation martensitic steel (CLAM) were irradiated in the fifth experiment of SINQ Target Irradiation Program (STIP-V) up to 20.1 dpa/1499 appm He/440 °C. Tensile tests were performed at room temperature (R.T) and irradiation temperatures (Tirr) in the range of 25-450 °C. The tensile results demonstrated strong effect of irradiation dose and irradiation temperature on hardening and embrittlement. With Tirr below ˜314 °C, CLAM steel specimens tested at R.T and Tirr showed similar evolution trend with irradiation dose, compared to other reduced activation ferritic/martensitic (RAFM) steels in similar irradiation conditions. At higher Tirr above ˜314 °C, it is interesting that the hardening effect decreases and the ductility seems to recover, probably due to a strong effect of high irradiation temperature.

  1. Characterization of the tensile properties of friction stir welded aluminum alloy joints based on axial force, traverse speed, and rotational speed

    NASA Astrophysics Data System (ADS)

    Panda, Biranchi; Garg, A.; Jian, Zhang; Heidarzadeh, Akbar; Gao, Liang

    2016-06-01

    Friction stir welding (FSW) process has gained attention in recent years because of its advantages over the conventional fusion welding process. These advantages include the absence of heat formation in the affected zone and the absence of large distortion, porosity, oxidation, and cracking. Experimental investigations are necessary to understand the physical behavior that causes the high tensile strength of welded joints of different metals and alloys. Existing literature indicates that tensile properties exhibit strong dependence on the rotational speed, traverse speed, and axial force of the tool that was used. Therefore, this study introduces the experimental procedure for measuring tensile properties, namely, ultimate tensile strength (UTS) and tensile elongation of the welded AA 7020 Al alloy. Experimental findings suggest that a welded part with high UTS can be achieved at a lower heat input compared with the high heat input condition. A numerical approach based on genetic programming is employed to produce the functional relationships between tensile properties and the three inputs (rotational speed, traverse speed, and axial force) of the FSW process. The formulated models were validated based on the experimental data, using the statistical metrics. The effect of the three inputs on the tensile properties was investigated using 2D and 3D analyses. A high UTS was achieved, including a rotational speed of 1050 r/min and traverse speed of 95 mm/min. The results also indicate that 8 kN axial force should be set prior to the FSW process.

  2. The elevated temperature tensile properties of S-200E commercially pure beryllium

    SciTech Connect

    Henshall, G.A.; Torres, S.G.; Hanafee, J.E.

    1995-03-01

    Experiments were performed at 300-100 C in longitudinal and transverse orientations at quasi-static strain rate 5.5 {times} 10{sup {minus}4}s{sup {minus}1}. Results show that the stress-strain curve is smooth, without yield points or serrations. Yield stress and ultimate tensile stress decrease monotonically with temperature. Similar strengths were measured for both orientations. Failure elongation vs temperature is complex.

  3. Acoustic emission monitoring of tensile testing of corroded and un-corroded clad aluminum 2024-T3 and characterization of effects of corrosion on AE source events and material tensile properties

    NASA Astrophysics Data System (ADS)

    Okafor, A. Chukwujekwu; Natarajan, Shridhar

    2014-02-01

    Corrosion damage affects structural integrity and deteriorates material properties of aluminum alloys in aircraft structures. Acoustic Emission (AE) is an effective nondestructive evaluation (NDE) technique for monitoring such damages and predicting failure in large structures of an aircraft. For successful interpretation of data from AE monitoring, sources of AE and factors affecting it need to be identified. This paper presents results of AE monitoring of tensile testing of corroded and un-corroded clad Aluminum 2024-T3 test specimens, and characterization of the effects of strain-rate and corrosion damage on material tensile properties and AE source events. Effect of corrosion was studied by inducing corrosion in the test specimens by accelerated corrosion testing in a Q-Fog accelerated corrosion chamber for 12 weeks. Eight (8) masked dog-bone shaped specimens were placed in the accelerated corrosion chamber at the beginning of the test. Two (2) dog-bone shaped specimens were removed from the corrosion chamber after exposure time of 3, 6, 9, and 12 weeks respectively, and subjected to tension testing till specimen failure along with AE monitoring, as well as two (2) reference samples not exposed to corrosion. Material tensile properties (yield strength, ultimate tensile strength, toughness, and elongation) obtained from tension test and AE parameters obtained from AE monitoring were analyzed and characterized. AE parameters increase with increase in exposure period of the specimens in the corrosive environment. Aluminum 2024-T3 is an acoustically silent material during tensile deformation without any damage. Acoustic emission events increase with increase of corrosion damage and with increase in strain rate above a certain value. Thus AE is suitable for structural health monitoring of corrosion damage. Ultimate tensile strength, toughness and elongation values decrease with increase of exposure period in corrosion chamber.

  4. Tensile properties of a titanium modified austenitic stainless steel and the weld joints after neutron irradiation

    SciTech Connect

    Shiba, Kiyoyuki; Ioka, Ikuo; Jitsukawa, Shiro; Hamada, Shozo; Hishinuma, Atkinichi; Robertson, J.P.

    1999-10-01

    Tensile specimens of a titanium modified austenitic stainless steel and its weldments fabricated with Tungsten Inert Gas (TIG) and Electron Beam (EB) welding techniques were irradiated to a peak dose of 19 dpa and a peak helium level of 250 appm in the temperature range between 200 and 400 C in spectrally tailored capsules in the Oak Ridge Research Reactor (ORR) and the High Flux Isotope Reactor (HFIR). The He/dpa ratio of about 13 appm/dpa is similar to the typical helium/.dpa ratio of a fusion reactor environment. The tensile tests were carried out at the irradiation temperature in vacuum. The irradiation caused an increase in yield stress to levels between 670 and 800 MPa depending on the irradiation temperature. Total elongation was reduced to less than 10%, however the specimens failed in a ductile manner. The results were compared with those of the specimens irradiated using irradiation capsules producing larger amount of He. Although the He/dpa ratio affected the microstructural change, the impact on the post irradiation tensile behavior was rather small not only for base metal specimens but also for the weld joint and the weld metal specimens.

  5. Response of Slub Characteristics on Tensile Properties of Injected Slub Yarn

    NASA Astrophysics Data System (ADS)

    Ray, N. C.; Mukhopadhyay, A.; Midha, V. K.

    2016-04-01

    Injected slub yarn is one of the most promising among different types of slub yarns. Present study embodies the effect of some important parameters like base yarn twist level, number of base yarn, twist direction and injected fibre components on injected slub yarn performance in terms of tensile strength and breaking elongation. In case of single base slub yarn, final yarn tenacity and elongation increases with the reduction of base yarn twist level keeping final yarn twist multiplier constant. However, the effect of base yarn twist level is marginal in case of injected slub yarn made with double base yarn. Yarn tenacity and elongation significantly higher in case of double base injected yarns as compared to single base injected yarn. The aforementioned tensile parameters of single base injected slub yarns reduce with the reduction of yarn linear density. However, in case of double base injected slub yarns, highest tenacity and elongation value are achieved for 2/80s yarn having finest yarn liner density among 2/40s, 2/60s and 2/80s yarns. In case of single base injected slub yarn, tensile strength is slightly higher and elongation values are significantly higher when injection component fibres changed from 100 % cotton to 50/50 polyester/cotton blended fibres which is just opposite to that of double base injected slub yarn. Results also showed that the twist direction in the base and final yarn influence the strength and elongation of injected slub yarns.

  6. Effect of filler loading of nickel zinc ferrite on the tensile properties of PLA nanocomposites

    NASA Astrophysics Data System (ADS)

    Shahdan, Dalila; Ahmad, Sahrim Hj

    2013-05-01

    The mechanical strength of magnetic polymer nanocomposite (MPNC) of nickel zinc (NiZn) ferrite nanoparticles incorporated with polylactic acid (PLA) and liquid natural rubber (LNR) as compatibilizer is reported. The matrix was prepared from PLA and LNR in the ratio of 90:10. The MPNC were prepared at constant mixing temperature at 180°C, mixing time of 15 min. and mixing speed of 100 rpm. In order to achieve a good dispersion of NiZn ferrite in the matrix, firstly an ultrasonic treatment had been employed to mix the LNR and NiZn ferrite for 1 hour. The MPNC of PLA/LNR/NiZn ferrite then were prepared via Thermo Haake internal mixer using melt-blending method from different filler loading from 1-5 wt% NiZn ferrite. The result of tensile tests showed that as the filler loading increases the tensile strength also increases until an optimum value of filler loading was reached. The Young's modulus, tensile strength and elongation at break have also increased. The study proves that NiZn ferrite is excellent reinforcement filler in PLA matrix. Scanning electron micrograph (SEM) and energy dispersive X-ray spectroscopy (EDX) were meant to show the homogeneity dispersion of nanoparticles within the matrix and to confirm the elemental composition of NiZn ferrites-PLA/LNR nanocomposites respectively.

  7. Tensile properties of a titanium modified austenitic stainless steel and the weld joints after neutron irradiation

    SciTech Connect

    Shiba, K.; Ioka, I.; Jitsukawa, S.; Hamada, A.; Hishinuma, A.

    1996-10-01

    Tensile specimens of a titanium modified austenitic stainless steel and its weldments fabricated with Tungsten Inert Gas (TIG) and Electron Beam (EB) welding techniques were irradiated to a peak dose of 19 dpa and a peak helium level of 250 appm in the temperature range between 200 and 400{degrees}C in spectrally tailored capsules in the Oak Ridge Research Reactor (ORR) and the High Flux Isotope Reactor (HFIR). The He/dpa ratio of about 13 appm/dpa is similar to the typical helium/dpa ratio of a fusion reactor environment. The tensile tests were carried out at the irradiation temperature in vacuum. The irradiation caused an increase in yield stress to levels between 670 and 800 MPa depending on the irradiation temperature. Total elongation was reduced to less than 10%, however the specimens failed in a ductile manner. The results were compared with those of the specimens irradiated using irradiation capsules producing larger amount of He. Although the He/dpa ratio affected the microstructural change, the impact on the post irradiation tensile behavior was rather small for not only base metal specimens but also for the weld joint and the weld metal specimens.

  8. Creep and tensile properties of several oxide-dispersion-strengthened nickel-base alloys at 1365 K

    NASA Technical Reports Server (NTRS)

    Wittenberger, J. D.

    1977-01-01

    The tensile properties at room temperature and at 1365 K and the tensile creep properties at low strain rates at 1365 K were measured for several oxide-dispersion-strengthened (ODS) alloys. The alloys examined included ODS Ni, ODS Ni-20Cr, and ODS Ni-16Cr-Al. Metallography of creep tested, large grain size ODS alloys indicated that creep of these alloys is an inhomogeneous process. All alloys appear to possess a threshold stress for creep. This threshold stress is believed to be associated with diffusional creep in the large grain size ODS alloys and normal dislocation motion in perfect single crystal (without transverse low angle boundaries) ODS alloys. Threshold stresses for large grain size ODS Ni-20Cr and Ni-16Cr-Al type alloys are dependent on the grain aspect ratio. Because of the deleterious effect of prior creep on room temperature mechanical properties of large grain size ODS alloys, it is speculated that the threshold stress may be the design limiting creep strength property.

  9. Discussion on FRP design properties based on flexural tests (ASTM D-790) and tensile tests (ASTM D-638)

    SciTech Connect

    Clark, J.M.

    1996-11-01

    Tensile and flexural test results on the same laminate can have significant difference with the reported flexural strength being up to 100% greater than the tensile strength using the standard ASTM reporting methods. Taken at face value, these results can lead to nonconservative designs. The flexural test method is much simpler and less expensive, but must be used with a clear understanding of how they were computed and with sound engineering judgment since the flexural strength is calculated with linear bending theory at failure loads that are usually in the nonlinear range. This is significant since the general accepted design practice is to use linear theory in the design of FRP equipment. Manufacturers reporting this value should thus have a clear understanding of the difference between the reported results for flexural strength and the required design strength. This paper shows how to determine the proper design value from a flexural test which results in safe designs of FRP equipment and shows that the reported flexural strength from the ASTM D-790 method should not be used in design of FRP equipment.

  10. Effects of Microstructure on Tensile, Charpy Impact, and Crack Tip Opening Displacement Properties of Two API X80 Pipeline Steels

    NASA Astrophysics Data System (ADS)

    Shin, Sang Yong

    2013-06-01

    The effects of microstructure on tensile, Charpy impact, and crack tip opening displacement (CTOD) properties of two API X80 pipeline steels were investigated in this study. Two API X80 pipeline steels consisting of acicular ferrite and granular bainite, and a small amount of hard phases such as martensite and secondary phases have elongated grains along the rolling direction, so that they show different mechanical properties as the specimens' directions change. The 90 deg specimens have high tensile strength due to the low stress concentration on the fine hard phases and the high loads for the deformation of the elongated grains. In contrast, the 30 deg specimens have less elongated grains and larger hard phases such as martensite, with the size of about 3 μm, than the 90 deg specimens. Hence, the 30 deg specimens have low tensile strength because of the high stress concentration on the large hard phases and the low loads to deform grains. In the 90 deg specimen, brittle crack propagation surfaces are even since cracks propagate in a straight line along the elongated grain structure. In the 30 deg specimen, however, brittle crack propagation surfaces are uneven, and secondary cracks are observed, because of the zigzag brittle crack propagation path. In the CTOD properties, the 90 deg specimens have maximum forces of higher magnitude than the 30 deg specimens, because of the elongated grain structure. However, CTODs of the 90 deg specimens are lower than those of the 30 deg specimens because of the low plastic deformation areas by the elongated grains in the 90 deg specimens.

  11. Effects of Long Term Thermal Exposure on Chemically Pure (CP) Titanium Grade 2 Room Temperature Tensile Properties and Microstructure

    NASA Technical Reports Server (NTRS)

    Ellis, David L.

    2007-01-01

    Room temperature tensile testing of Chemically Pure (CP) Titanium Grade 2 was conducted for as-received commercially produced sheet and following thermal exposure at 550 and 650 K for times up to 5,000 h. No significant changes in microstructure or failure mechanism were observed. A statistical analysis of the data was performed. Small statistical differences were found, but all properties were well above minimum values for CP Ti Grade 2 as defined by ASTM standards and likely would fall within normal variation of the material.

  12. Effect of nitrogen on tensile properties and structures of T-111 (tantalum, 8 percent tungsten, 2 percent hafnium) tubing

    NASA Technical Reports Server (NTRS)

    Buzzard, R. J.; Metroka, R. R.

    1973-01-01

    The effect of controlled nitrogen additions was evaluated on the mechanical properties of T-111 (Ta-8W-2Hf) fuel pin cladding material proposed for use in a lithium-cooled nuclear reactor concept. Additions of 80 to 1125 ppm nitrogen resulted in increased strengthening of T-111 tubular section test specimens at temperatures of 25 to 1200 C. Homogeneous distributions of up to 500 ppm nitrogen did not seriously decrease tensile ductility. Both single and two-phase microstructures, with hafnium nitride as the second phase, were evaluated in this study.

  13. Effects of Mo, Cr, and V Additions on Tensile and Charpy Impact Properties of API X80 Pipeline Steels

    NASA Astrophysics Data System (ADS)

    Han, Seung Youb; Shin, Sang Yong; Seo, Chang-Hyo; Lee, Hakcheol; Bae, Jin-Ho; Kim, Kisoo; Lee, Sunghak; Kim, Nack J.

    2009-08-01

    In this study, four API X80 pipeline steels were fabricated by varying Mo, Cr, and V additions, and their microstructures and crystallographic orientations were analyzed to investigate the effects of their alloying compositions on tensile properties and Charpy impact properties. Because additions of Mo and V promoted the formation of fine acicular ferrite (AF) and granular bainite (GB) while prohibiting the formation of coarse GB, they increased the strength and upper-shelf energy (USE) and decreased the energy transition temperature (ETT). The addition of Cr promoted the formation of coarse GB and hard secondary phases, thereby leading to an increased effective grain size, ETT, and strength, and a decreased USE. The addition of V resulted in a higher strength, a higher USE, a smaller effective grain size, and a lower ETT, because it promoted the formation of fine and homogeneous of AF and GB. The steel that contains 0.3 wt pct Mo and 0.06 wt pct V without Cr had the highest USE and the lowest ETT, because its microstructure was composed of fine AF and GB while its maintained excellent tensile properties.

  14. Elevated-temperature tensile properties of three heats of commercially heat-treated Alloy 718

    SciTech Connect

    Booker, M.K.; Booker, B.L.P.

    1980-03-01

    Three heats of commercially heat-treated alloy 718 were tensile tested over the temperature range from room temperature to 816{degree}C and at nominal strain rates from 6.7 {times} 10{sup {minus}6} to 6.7 {times} 10{sup {minus}3}/s. We examined data for yield strength, ultimate tensile strength, uniform elongation, total elongation, and reduction in area and also inspected tensile stress-strain behavior. Yield and ultimate tensile strengths for commercially heat-treated alloy 718 decrease very gradually with temperature from room temperature up to about 600{degree}C for a strain rate of 6.7 {times} 10{sup {minus}5}/s or to about 700{degree}C for a strain rate of 6.7 {times} 10{sup {minus}4}/s. Above these temperatures the strength drops off fairly rapidly. Reduction in area and total elongation data show minimum around 700{degree}C, with each ductility measure falling to 10% or less at the minimum. This minimum is more pranced and occurs at lower temperatures as strain rate decreases. Up to about 600{degree}C the ductility is typically around 30%. As the temperature reaches 816{degree}C the ductility again increases to perhaps 60%. The uniform elongation (plastic strain at peak load) decreases only slightly with temperature to about 500{degree}C then drops off rapidly and monotonically with temperature, reaching values less than 1% at 816{degree}C. At the highest test temperatures the load maximum may result, not from necking of the specimen, but from overaging of the precipitation-hardened microstructure. Stress-strain curves showed serrated deformations in the temperature range from 316 to 649{degree}C, although they occur only for the faster strain rates at the supper end of this temperature range. The serrations can be quite large, involving load drops of perhaps 40 to 80 MPa. The serrations typically begin within the first 2% of deformation and continue until fracture, although exceptions were noted. 16 refs., 14 figs., 3 tabs.

  15. Tensile properties and structure of several superalloys after long-term exposure to LiF and vacuum at 1,173 K

    SciTech Connect

    Whittenberger, J.D.

    1995-12-01

    The use of the solid-to-liquid phase transformation of LiF to store thermal energy is under consideration for a space-based solar dynamic system. Although advantageous in terms of its energy density, the melting point of this salt (1,121 K) is beyond the commonly accepted upper-use temperature of 1,100 K for chromium-bearing superalloys in vacuum. However, one commercially available nickel-base superalloy (Hastelloy B-2) is chromium free; unfortunately, because of its high molybdenum content, this alloy can form phases that cause high-temperature embrittlement. To test the suitability of Hastelloy B-2, it has been exposed to molten LiF, its vapor and vacuum at 1,173 K for 2,500, 5,000, and 10{sup 4} h. For control, the chromium-containing cobalt-base Haynes alloy 188 and nickel-base Haynes alloy 230 were also exposed to LiF and vacuum at 1,173 K for 5,000 h. Neither LiF nor vacuum exposures had any significant effect on Hastelloy B-2 in terms of microstructural surface damage or weight change. Measurement of the post exposure tensile properties of Hastelloy B-2, nevertheless, revealed low tensile ductility at 1,050 K. Such embrittlement and low strength at elevated temperatures appear to preclude the use of Hastelloy B-2 as a containment material for LiF. Little evidence of significant attack by LiF was seen in either of the chromium-containing superalloys; however, considerable weight loss and near-surface microstructural damage occurred in both alloys exposed to vacuum. Although measurement of the post exposure room-temperature tensile properties of Haynes alloys 188 and 230 revealed no significant loss of strength or ductility, the severe degree of microstructural damage found in unshielded alloys exposed to vacuum indicates that chromium-bearing superalloys might also be unsuitable for prolonged containment of LiF in space above 1,100 K.

  16. Microstructure and tensile properties of iron parts fabricated by selective laser melting

    NASA Astrophysics Data System (ADS)

    Song, Bo; Dong, Shujuan; Deng, Sihao; Liao, Hanlin; Coddet, Christian

    2014-03-01

    Iron, as the basic industry material was extensively studied in the past, but it could still offer extended possibilities with the use of new processing techniques such as selective laser melting (SLM). In this work, the manufacturing of iron parts using SLM technology was investigated. The effect of processing parameters on density of the iron parts was studied. Fully dense iron parts have been fabricated at the laser power of 100 W using different laser scanning speeds. By means of metallographic observation and TEM characterization, it can be found that the grains size decreased with increasing scanning speed and high dislocation density was observed. Tensile specimens were fabricated using optimal parameters and mechanical tests allowed observing an ultimate tensile strength of 412 MPa and the yield strength of 305 MPa. Multiple self-strengthening mechanisms during SLM process are proposed to explain this high mechanical strength. The grain refinement seems to be the most significant strengthening mechanism, followed by work hardening arising from the high cooling rate.

  17. Tensile properties of nicalon fiber-reinforced carbon following aerospace turbine engine testing

    NASA Astrophysics Data System (ADS)

    Pierce, J. L.; Zawada, L. P.; Srinivasan, R.

    2003-06-01

    The durability of coated Nicalon silicon carbide fiber-reinforced carbon (SiC/C) as the flap and seal exhaust nozzle components in a military aerospace turbine engine was studied. Test specimens machined from both a flap and a seal component were tested for residual strength following extended ground engine testing on a General Electric F414 afterburning turbofan engine. Although small amounts of damage to the protective exterior coating were identified on each component following engine testing, the tensile strengths were equal to the as-fabricated tensile strength of the material. Differences in strength between the two components and variability within the data sets could be traced back to the fabrication process using witness coupon test data from the manufacturer. It was also observed that test specimens machined transversely across the flap and seal components were stronger than those machined along the length. The excellent retained strength of the coated SiC/C material after extended exposure to the severe environment in the afterburner exhaust section of an aerospace turbofan engine has resulted in this material being selected as the baseline material for the F414 exhaust nozzle system.

  18. Effects of heat input on microstructure and tensile properties of laser welded magnesium alloy AZ31

    SciTech Connect

    Quan, Y.J. Chen, Z.H.; Gong, X.S.; Yu, Z.H.

    2008-10-15

    A 3 kW CO{sub 2} laser beam was used to join wrought magnesium alloy AZ31 sheets, and the effects of heat input on the quality of butt welding joints were studied. By macro and microanalysis, it is found that the welding heat input plays an important role in laser welding process for AZ31 wrought sheets. After welding, the grains far from the weld centre present the typical rolled structure. But the microstructure out of the fusion zone gradually changes to complete equiaxed crystals as the distance from the weld centre decreases. Adjacent to the fusion boundary, there is a band region with columnar grains, and its growth direction is obviously perpendicular to the solid/liquid line. The microstructure in fusion centre consists of fine equiaxed grains and the many precipitated particles are brittle phase Mg{sub 17}Al{sub 12} or Mg{sub 17}(Al,Zn){sub 12}. With increasing the heat input, the band width of columnar grains varies, the grains in fusion zone get coarser, and the distribution of precipitates changes from intragranularly scattered particles to intergranularly packed ones. The results of tensile test show that the change trend of ultimate tensile strength (UTS) and elongation of the welded joints is to increase at first and then decrease with the heat input increasing. When the heat input reaches 24 J mm{sup -1}, the maximum value of the UTS is up to 96.8% of the base metal.

  19. Tensile and electrical properties of copper alloys irradiated in a fission reactor

    SciTech Connect

    Fabritsiev, S.A.; Pokrovsky, A.S.; Zinkle, S.J.; Rowcliffe, A.F.

    1996-04-01

    Postirradiation electrical sensitivity and tensile measurements have been completed on pure copper and copper alloy sheet tensile specimens irradiated in the SM-2 reactor to doses of {approx}0.5 to 5 dpa and temperatures between {approx}80 and 400{degrees}C. Considerable radiation hardening and accompanying embrittlement was observed in all of the specimens at irradiation temperature below 200{degrees}C. The radiation-induced electrical conductivity degradation consisted of two main components: solid transmutation effects and radiation damage (defect cluster and particle dissolution) effects. The radiation damage component was nearly constant for the doses in this study, with a value of {approx}1.2n{Omega}m for pure copper and {approx}1.6n{Omega}m for dispersion strengthened copper irradiated at {approx}100{degrees}C. The solid transmutation component was proportional to the thermal neutron flux, and became larger than the radiation damage component for fluences larger than {approx}5 10{sup 24} n.m{sup 2}. The radiation hardening and electrical conductivity degradation decreased with increasing irradiation temperature, and became negligible for temperatures above {approx}300{degrees}C.

  20. Electro-mechanical Properties of Carbon Nanotubes: Effect of Small Tensile and Torsional Strains

    NASA Technical Reports Server (NTRS)

    Anantram, M. P.; Yang, Liu; Han, Jie; Liu, J. P.; Saini, Subhash (Technical Monitor)

    1999-01-01

    We present a simple picture to calculate the bandgap ($E_g$) of carbon nanotubes (CNT) in the presence of uniform torsional and tensile strain ($\\sigma$). We find that under tensile strain, $ absolute value of dE_g/d\\sigma$ of zig-zag tubes is approximately equal to $3t_0$, where $t_0$ is the hopping parameter. Further, $ absolute value of dE_g/d\\sigma$ decreases as the chirality changes to armchair, where it takes the value zero. The sign of $dE_g/d\\sigma$ follows the $(N_x-N_y) *mod 3$(equal to - 1, 0 and +1) rule. In contrast to the above, we show that under torsional strain, $absolute value of dE_g/d\\sigma$ of armchair tubes is approximately equal to $3t_0$ and continually decreases as the chirality changes to zig-zag, where is takes a small value. The sign of $dE_g/d\\sigma$ again follows the $(N_x-N_y)*mod 3$ rule. Finally, we predict a change in the sign of $dE_g/d\\sigma$ as function of strain, corresponding to a change in the value of $q$ that corresponds to the bandgap minimum.

  1. Tuning the Electro-optical Properties of Germanium Nanowires by Tensile Strain

    PubMed Central

    2012-01-01

    In this Letter we present the electrical and electro-optical characterization of single crystalline germanium nanowires (NWs) under tensile strain conditions. The measurements were performed on vapor–liquid–solid (VLS) grown germanium (Ge) NWs, monolithically integrated into a micromechanical 3-point strain module. Uniaxial stress is applied along the ⟨111⟩ growth direction of individual, 100 nm thick Ge NWs while at the same time performing electrical and optical characterization at room temperature. Compared to bulk germanium, an anomalously high and negative-signed piezoresistive coefficient has been found. Spectrally resolved photocurrent characterization on strained NWs gives experimental evidence on the strain-induced modifications of the band structure. Particularly we are revealing a rapid decrease in resistivity and a red-shift in photocurrent spectra under high strain conditions. For a tensile strain of 1.8%, resistivity decreased by a factor of 30, and the photocurrent spectra shifted by 88 meV. Individual stressed NWs are recognized as an ideal platform for the exploration of strain-related electronic and optical effects and may contribute significantly to the realization of novel optoelectronic devices, strain-enhanced field-effect transistors (FETs), or highly sensitive strain gauges. PMID:23146072

  2. Equal-channel angular pressing of commercial aluminum alloys: Grain refinement, thermal stability and tensile properties

    SciTech Connect

    Horita, Zenji; Fujinami, Takayoshi; Nemoto, Minoru; Langdon, T.G.

    2000-03-01

    Using equal-channel angular (ECA) pressing at room temperature, the grain sizes of six different commercial aluminum-based alloys (1100, 2024, 3004, 5083, 6061, and 7075) were reduced to within the submicrometer range. These grains were reasonably stable up to annealing temperatures of {approximately} 200 C and the submicrometer grains were retained in the 2024 and 7075 alloys to annealing temperatures of 300 C. Tensile testing after ECA pressing through a single pass, equivalent to the introduction of a strain of {approximately}1, showed there is a significant increase in the values of the 0.2 pct proof stress and the ultimate tensile stress (UTS) for each alloy with a corresponding reduction in the elongations to failure. It is demonstrated that the magnitudes of these stresses scale with the square rot of the Mg content in each alloy. Similar values for the proof stresses and the UTS were attained at the same equivalent strains in samples subjected to cold rolling, but the elongations to failure were higher after ECA pressing to equivalent strains >1 because of the introduction of a very small grain size. Detailed results for the 1100 and 3004 alloys show good agreement with the standard Hall-Petch relationship.

  3. Effects of Finish Cooling Temperature on Tensile Properties After Thermal Aging of Strain-Based API X60 Linepipe Steels

    NASA Astrophysics Data System (ADS)

    Sung, Hyo Kyung; Lee, Dong Ho; Shin, Sang Yong; Lee, Sunghak; Ro, Yunjo; Lee, Chang Sun; Hwang, Byoungchul

    2015-09-01

    Two types of strain-based American Petroleum Institute (API) X60 linepipe steels were fabricated at two finish cooling temperatures, 673 K and 723 K (400 °C and 450 °C), and the effects of the finish cooling temperatures on the tensile properties after thermal aging were investigated. The strain-based API X60 linepipe steels consisted mainly of polygonal ferrite (PF) or quasi-polygonal ferrite and the volume fraction of acicular ferrite increased with the increasing finish cooling temperature. In contrast, the volume fractions of bainitic ferrite (BF) and secondary phases decreased. The tensile properties before and after thermal aging at 473 K and 523 K (200 °C and 250 °C) were measured. The yield strength, ultimate tensile strength, and yield ratio increased with the increasing thermal aging temperature. The strain hardening rate in the steel fabricated at the higher finish cooling temperature decreased rapidly after thermal aging, probably due to the Cottrell atmosphere, whereas the strain hardening rate in the steel fabricated at the lower finish cooling temperature changed slightly after thermal aging. The uniform elongation and total elongation decreased with increasing thermal aging temperature, probably due to the interactions between carbon atoms and dislocations. The uniform elongation decreased rapidly with the decreasing volume fractions of BF and martensite and secondary phases. The yield ratio increased with the increasing thermal aging temperature, whereas the strain hardening exponent decreased. The strain hardening exponent of PL steel decreased rapidly after thermal aging because of the large number of mobile dislocations between PF and BF or martensite or secondary phases.

  4. 41 CFR 102-75.1155 - May an acceptable gift of property be converted to money?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... of property be converted to money? 102-75.1155 Section 102-75.1155 Public Contracts and Property...-75.1155 May an acceptable gift of property be converted to money? GSA can determine whether or not a gift of property can and should be converted to money. After conversion, GSA must deposit the...

  5. THE EFFECTS OF FAST REACTOR IRRADIATION CONDITIONS ON THE TENSILE PROPERTIES OF TWO FERRITIC/MARTENSITIC STEELS

    SciTech Connect

    Maloy, Stuart A.; Toloczko, Mychailo B.; McClellan, K. J.; Romero, T. J.; Kohno, Y.; Garner, Francis A.; Kurtz, Richard J.; Kimura, Akihiko

    2006-09-15

    Tensile testing has been performed at 25 and at ~400°C on two ferritic/martensitic steels (JFMS and HT-9) after irradiation in FFTF to up to ~70 dpa at 373 to 433°C. As observed in previous studies, this range of irradiation temperatures has a significant effect on hardening. The percent increase in yield stress decreases with increasing irradiation temperature from 373 to 433ºC. The JFMS alloy, which has 0.7 wt. % silicon, exhibits approximately a factor of two increase in yield strength between tests at 427°C and at 373°C, and shows an increase in hardening with increasing dose. A comparison of the JFMS tensile properties to the properties of other ferritic/martensitic steels suggests that this hardening is due to precipitation of a Si-rich Laves phase in this alloy. The HT-9 alloy, which contains more chromium and more carbon but less silicon (0.2 wt. %), less molybdenum and less nickel, hardens during irradiation at 373°C, but shows less hardening for irradiations performed at 427ºC and no increase in yield stress with increasing dose beyond 10 dpa.

  6. The effects of fast reactor irradiation conditions on the tensile properties of two ferritic/martensitic steels

    NASA Astrophysics Data System (ADS)

    Maloy, Stuart A.; Toloczko, M. B.; McClellan, K. J.; Romero, T.; Kohno, Y.; Garner, F. A.; Kurtz, R. J.; Kimura, A.

    2006-09-01

    Tensile testing has been performed at 25 and at ˜400 °C on two ferritic/martensitic steels (JFMS and HT-9) after irradiation in FFTF to up to ˜70 dpa at 373-433 °C. As observed in previous studies, this range of irradiation temperatures has a significant effect on hardening. The percent increase in yield stress decreases with increasing irradiation temperature from 373 to 433 °C. The JFMS alloy, which has 0.7 wt% silicon, exhibits approximately a factor of two increase in yield strength between tests at 427 and at 373 °C, and shows an increase in hardening with increasing dose. A comparison of the JFMS tensile properties to the properties of other ferritic/martensitic steels suggests that this hardening is due to precipitation of a Si-rich laves phase in this alloy. The HT-9 alloy, which contains more chromium and more carbon but less silicon (0.2 wt%), less molybdenum and less nickel, hardens during irradiation at 373 °C, but shows less hardening for irradiations performed at 427 °C and no increase in yield stress with increasing dose beyond 10 dpa.

  7. Microstructure and Tensile Properties of BN/SiC Coated Hi-Nicalon, and Sylramic SiC Fiber Preforms

    NASA Technical Reports Server (NTRS)

    Bhatt, Ramakrishna T.; Chen, Yuan L.; Morscher, Gregory N.

    2001-01-01

    Batch to batch and within batch variations, and the influence of fiber architecture on room temperature physical and tensile properties of BN/SiC coated Hi-Nicalon and Sylramic SiC fiber preform specimens were determined. The three fiber architectures studied were plain weave (PW), 5-harness satin (5HS) and 8-harness satin (8HS) Results indicate that the physical properties vary up to 10 percent within a batch, and up to 20 percent between batches of preforms. Load-reload (Hysteresis) and acoustic emission methods were used to analyze damage accumulation occurring during tensile loading. Early acoustic emission activity, before observable hysteretic behavior, indicates that the damage starts with the formation of nonbridged tunnel cracks. These cracks then propagate and intersect the load bearing "0" fibers giving rise to hysteretic behavior, For the Hi-Nicalon preform specimens, the onset of "0" bundle cracking stress and strain appeared to be independent of the fiber architecture. Also, the "0" fiber bundle cracking strain remained nearly the same for the preform specimens of both fiber types. Transmission Electron Microscope (TEM) analysis indicates that the Chemical Vapor Infiltration (CVI) Boron Nitride (BN) interface coating is mostly amorphous and contains carbon and oxygen impurities, and the CVI SiC coating is crystalline. No reaction exists between the CVI BN and SiC coating.

  8. Static and fatigue tensile properties of cross-ply laminates containing vascules for self-healing applications

    NASA Astrophysics Data System (ADS)

    Luterbacher, R.; Trask, R. S.; Bond, I. P.

    2016-01-01

    The effect of including hollow channels (vascules) within cross-ply laminates on static tensile properties and fatigue performance is investigated. No change in mechanical properties or damage formation is observed when a single vascule is included in the 0/90 interface, representing 0.5% of the cross sectional area within the specimen. During tensile loading, matrix cracks develop in the 90° layers leading to a reduction of stiffness and strength (defined as the loss of linearity) and a healing agent is injected through the vascules in order to heal them and mitigate the caused degradation. Two different healing agents, a commercial low viscosity epoxy resin (RT151, Resintech) and a toughened epoxy blend (bespoke, in-house formulation) have been used to successfully recover stiffness under static loading conditions. The RT151 system recovered 75% of the initial failure strength, whereas the toughened epoxy blend achieved a recovery of 67%. Under fatigue conditions, post healing, a rapid decay of stiffness was observed as the healed damage re-opened within the first 2500 cycles. This was caused by the high fatigue loading intensity, which was near the static failure strength of the healing resin. However, the potential for ameliorating (via self-healing or autonomous repair) more diffuse transverse matrix damage via a vascular network has been shown.

  9. The Effect of Grain Size and Dislocation Density on the Tensile Properties of Ni-SiCNP Composites During Annealing

    NASA Astrophysics Data System (ADS)

    Yang, Chao; Huang, Hefei; Thorogood, Gordon James; Jiang, Li; Ye, Xiangxi; Li, Zhijun; Zhou, Xingtai

    2016-03-01

    The grain size refinement, enhancement of mechanical properties, and static recrystallization behavior of metallic nickel-silicon carbide nano-particle (Ni-3wt.%SiCNP) composites, milled for times ranging from 8 to 48 h have been examined. One set of Ni-SiCNP composite samples were annealed at 300 °C for 250 h, while the other set of samples were maintained at room temperature for control purposes (reference). The electron backscatter diffraction results indicate that the grain size of the annealed Ni-SiCNP composite was refined due to grain restructuring during static recrystallization. The x-ray diffraction results indicate that low-temperature annealing effectively reduced the density of dislocations; this can be explained by the dislocation pile-up model. Additionally, the tensile tests indicated that the annealed Ni-SiCNP composite had a significant increase in strength due to an increase of the Hall-Petch strengthening effect with a slight increase in the total elongation. The decrease of dislocation pile-up in the grain interiors and the increase in grain boundary sliding are assumed to be the main mechanisms at play. The relationship between the microstructural evolution and the variation of tensile properties is examined in this study.

  10. Effect of Austenite Stability on Microstructural Evolution and Tensile Properties in Intercritically Annealed Medium-Mn Lightweight Steels

    NASA Astrophysics Data System (ADS)

    Song, Hyejin; Sohn, Seok Su; Kwak, Jai-Hyun; Lee, Byeong-Joo; Lee, Sunghak

    2016-06-01

    The microstructural evolution with varying intercritical-annealing temperatures of medium-Mn ( α + γ) duplex lightweight steels and its effects on tensile properties were investigated in relation to the stability of austenite. The size and volume fraction of austenite grains increased as the annealing temperature increased from 1123 K to 1173 K (850 °C to 900 °C), which corresponded with the thermodynamic calculation data. When the annealing temperature increased further to 1223 K (950 °C), the size and volume fraction were reduced by the formation of athermal α'-martensite during the cooling because the thermal stability of austenite deteriorated as a result of the decrease in C and Mn contents. In order to obtain the best combination of strength and ductility by a transformation-induced plasticity (TRIP) mechanism, an appropriate mechanical stability of austenite was needed and could be achieved when fine austenite grains (size: 1.4 μm, volume fraction: 0.26) were homogenously distributed in the ferrite matrix, as in the 1123 K (850 °C)—annealed steel. This best combination was attributed to the requirement of sufficient deformation for TRIP and the formation of many deformation bands at ferrite grains in both austenite and ferrite bands. Since this medium-Mn lightweight steel has excellent tensile properties as well as reduced alloying costs and weight savings, it holds promise for new automotive applications.

  11. Microstructures and Tensile Mechanical Properties of Titanium Rods Made by Powder Compact Extrusion of a Titanium Hydride Powder

    NASA Astrophysics Data System (ADS)

    Zheng, Yifeng; Yao, Xun; Liang, Jiamiao; Zhang, Deliang

    2016-04-01

    Nearly fully dense titanium with good mechanical properties was fabricated rapidly by induction heating, holding, and hot extrusion of the TiH2 powder compacts. The dehydrogenation and consolidation processes took less than 15 minutes in total. The microstructures, contents of interstitial elements (H, O), tensile mechanical properties, and fracture behaviors of titanium samples made with different holding and extrusion temperatures [1273 K, 1373 K, and 1473 K (1000 °C, 1100 °C, and 1200 °C)] were investigated. The results showed that the hydrogen content in the extruded rods was around 0.09 wt pct when the holding and extrusion temperature was 1373 K or 1473 K (1100 °C or 1200 °C), with almost all of the TiH2 phase being transformed into Ti phase during the heating, holding, and extrusion process steps. The extruded Ti samples had a lamellar structure consisting of fine α lamellae with random orientations in different lamellar colonies and the relative density of all the extruded samples exceeded 99.5 pct. The residual TiH2 phase can reduce the ductility of extruded rods. The sample extruded at 1373 K (1100 °C) has the best elongation to fracture of 21.0 pct, and its average yield strength and ultimate tensile strength reached 536.8 and 691.8 MPa, respectively.

  12. Tensile properties and interfacial bonding of multi-layered, high-purity titanium strips fabricated by ARB process.

    PubMed

    Ghafari-Gousheh, Soroush; Nedjad, Syamak Hossein; Khalil-Allafi, Jafar

    2015-11-01

    Severe plastic deformation (SPD) processing has shown very effective in promotion of mechanical properties of metals and alloys. In this study, the results of investigating mechanical properties and also inter-layer bond performance of accumulative roll bonded high purity titanium (HP-Ti) strips are presented. High purity titanium plates were severely deformed by use of a combination of cold rolling (CR) to a thickness reduction of approximately 87% and then accumulative roll bonding (ARB) for three cycles (N=3) at ambient temperature. Optical and scanning electron microscopy, tensile testing, and hardness measurements were conducted. The ARB strips exhibited lower tensile strength and ductility in comparison to cold rolled one which can basically be attributed to the poor function of the latest bonds established in the centerlines of the strips. Fractographic examinations revealed the interfacial de-bonding along the centerline between the layers having undergone roll bonding for just one cycle. It was while the interfaces having experienced roll bonding for more cycles showed much higher resistance against delaminating. PMID:26253205

  13. Effect of rolling in the intercritical region on the tensile properties of dual-phase steel

    SciTech Connect

    Ahmad, E.; Priestner, R.

    1998-12-01

    A steel containing 0.088 wt% C, 1.2 wt% Mn, and 0.78 wt% Cr was rolled at intercritical temperature (790 C) and quenched to produce dual-phase microstructure. Rolling caused anisotropic increase in tensile strength and little change in ductility. The results suggest that rolling increased strength by a combination of strengthening of the ferrite and an increase in the stress transferred to the martensite. Up to 20% rolling reduction strengthened the ferrite by work hardening, larger reductions then reduced the strength of ferrite, anisotropically, due to increased recovery. Subgrains in ferrite were observed after rolling in the intercritical region which can contribute to the ultimate strength of the rolled material.

  14. Tensile properties and damage microstructures in ORR/HFIR-irradiated austenitic stainless steels

    NASA Astrophysics Data System (ADS)

    Wakai, E.; Hashimoto, N.; Robertson, J. P.; Jistukawa, S.; Sawai, T.; Hishinuma, A.

    2000-12-01

    The synergistic effect of displacement damage and helium generation under neutron irradiation on tensile behavior and microstructures of austenitic stainless steels was investigated. The steels were irradiated at 400°C in the spectrally-tailored (ST) Oak Ridge research reactor/high flux isotope reactor (ORR/HFIR) capsule to 17 dpa with a helium production of about 200 appm and in the HFIR target capsule to 21 and 34 dpa with 1590 and 2500 appm He, respectively. The increase of yield strength in the target irradiation was larger than that in the ST irradiation because of the high-number density of Frank loops, bubbles, voids, and carbides. Based on the theory of dispersed barrier hardening, the strengths evaluated from these clusters coincide with the measured increase of yield strengths. This analysis suggests that the main factors of radiation hardening in the ST and the target irradiation at 400°C are Frank-type loops and cavities, respectively.

  15. Optimizing the tensile properties of polyvinyl alcohol hydrogel for the construction of a bioprosthetic heart valve stent.

    PubMed

    Wan, W K; Campbell, G; Zhang, Z F; Hui, A J; Boughner, D R

    2002-01-01

    Although bioprosthetic heart valves offer the benefits of a natural opening and closing, better hemodynamics, and avoidance of life-long anticoagulant therapy, they nevertheless tend to fail in 10-15 years from tears and calcification. Several authors, including the present ones, have identified the rigid stent as a factor contributing to these failures. The ultimate solution is an artificial heart valve that has mechanical properties that allow it to move in conformity with the aortic root during the cardiac cycle, has superior hemodynamics, is nonthrombogenic, will last more than 20 years, and mitigates the need for anticoagulants. We have identified a polymer, polyvinyl alcohol (PVA) hydrogel, that has mechanical properties similar to soft tissue. The purpose of this research is to match the tensile properties of PVA to the porcine aortic root and to fabricate a stent prototype for a bioprosthetic heart valve with the use of the PVA hydrogel. Specimens of 15% w/w PVA were prepared by processing through 1-6 cycles of freezing (-20 degrees C) at 0.2 degrees C/min freeze rate and thawing (+20 degrees C) at different thawing rates (0.2 degrees C/min and 1 degrees C/min), for different holding times (1 and 6 h) at -20 degrees C. Subsequently tensile tests and stress-relaxation tests were conducted on the specimens. The different holding times at -20 degrees C demonstrated no difference in the result. The slower thawing rate improved the tensile properties but did not produce significant changes on the stress-relaxation properties. The nonlinear stress-strain curve for the PVA after the fourth freeze-thaw cycle matched the porcine aortic root within the physiological pressure range. The stress-relaxation curve for PVA also approximated the shape of the aortic root. The complex geometry of an artificial heart valve stent was successfully injection molded. These results, in combination with other preliminary findings for biocompatibility and fatigue behavior, suggest

  16. Thermal, tensile and rheological properties of high density polyethylene (HDPE) processed and irradiated by gamma-ray in different atmospheres

    SciTech Connect

    Ferreto, H. F. R. E-mail: ana-feitoza@yahoo.com.br; Oliveira, A. C. F. E-mail: ana-feitoza@yahoo.com.br; Parra, D. F. E-mail: ablugao@ipen.br; Lugão, A. B. E-mail: ablugao@ipen.br; Gaia, R.

    2014-05-15

    The aim of this paper is to investigate structural changes of high density polyethylene (HDPE) modified by ionizing radiation (gamma rays) in different atmospheres. The gamma radiation process for modification of commercial polymers is a widely applied technique to promote new physical-chemical and mechanical properties. Gamma irradiation originates free radicals which can induce chain scission or recombination, providing its annihilation, branching or crosslinking. This polymer was irradiated with gamma source of {sup 60}Co at doses of 5, 10, 20, 50 or 100 kGy at a dose rate of 5 kGy/h. The changes in molecular structure of HDPE, after gamma irradiations were evaluated using thermogravimetric analysis (TGA) and tensile machine and oscillatory rheology. The results showed the variations of the properties depending on the dose at each atmosphere.

  17. Effect of native oxide layers on copper thin-film tensile properties: A reactive molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Skarlinski, Michael D.; Quesnel, David J.

    2015-12-01

    Metal-oxide layers are likely to be present on metallic nano-structures due to either environmental exposure during use, or high temperature processing techniques such as annealing. It is well known that nano-structured metals have vastly different mechanical properties from bulk metals; however, difficulties in modeling the transition between metallic and ionic bonding have prevented the computational investigation of the effects of oxide surface layers. Newly developed charge-optimized many body [Liang et al., Mater. Sci. Eng., R 74, 255 (2013)] potentials are used to perform fully reactive molecular dynamics simulations which elucidate the effects that metal-oxide layers have on the mechanical properties of a copper thin-film. Simulated tensile tests are performed on thin-films while using different strain-rates, temperatures, and oxide thicknesses to evaluate changes in yield stress, modulus, and failure mechanisms. Findings indicate that copper-thin film mechanical properties are strongly affected by native oxide layers. The formed oxide layers have an amorphous structure with lower Cu-O bond-densities than bulk CuO, and a mixture of Cu2O and CuO charge character. It is found that oxidation will cause modifications to the strain response of the elastic modulii, producing a stiffened modulii at low temperatures (<75 K) and low strain values (<5%), and a softened modulii at higher temperatures. While under strain, structural reorganization within the oxide layers facilitates brittle yielding through nucleation of defects across the oxide/metal interface. The oxide-free copper thin-film yielding mechanism is found to be a tensile-axis reorientation and grain creation. The oxide layers change the observed yielding mechanism, allowing for the inner copper thin-film to sustain an FCC-to-BCC transition during yielding. The mechanical properties are fit to a thermodynamic model based on classical nucleation theory. The fit implies that the oxidation of the films

  18. The effect of postprocessing on tensile property and microstructure evolution of friction stir welding aluminum alloy joint

    SciTech Connect

    Hu, Z.L.; Wang, X.S.; Pang, Q.; Huang, F.; Qin, X.P.; Hua, L.

    2015-01-15

    Friction stir welding is an efficient manufacturing method for joining aluminum alloy and can dramatically reduce grain size conferring excellent plastic deformation properties. Consequently, friction stir welding is used to manufacture tailor welded blanks to optimize weight or performance in the final component. In the study, the microstructural evolution and mechanical properties of friction stir welding joint during plastic forming and subsequent heat treatment were investigated. The microstructural characteristics of the friction stir welding joints were studied by Electron Backscattered Diffraction and Transmission Electron Microscopy. The mechanical properties were evaluated by tensile and microhardness tests. It is found that the tensile and yield strengths of friction stir welding joints are significantly improved after severe plastic deformation due to the grain refinement. Following heat treatment, the strength of the friction stir welding joints significantly decrease due to the obvious abnormal grain growth. Careful attention must be given to the processing route of any friction stir welding joint intended for plastic forming, especially the annealing between forming passes. Severe plastic deforming of the friction stir welding joint leads to a high level of stored energy/dislocation density, which causes the abnormal grain growth during subsequent heat treatment, and consequently reduce the mechanical properties of the friction stir welding joint. - Highlights: • Great changes are observed in the microstructure of FSW joint after postprocessing. • Postprocessing shows great effect on the microstructure stability of FSW joint. • The weld shows more significant decrease in strength than the BM due to the AGG. • Attention must be given to the processing route of FSW joint for plastic forming.

  19. 49 CFR 1546.201 - Acceptance and screening of individuals and accessible property.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Acceptance and screening of individuals and... FOREIGN AIR CARRIER SECURITY Operations § 1546.201 Acceptance and screening of individuals and accessible... or accessible property before boarding an aircraft or entering a sterile area. (b) Screening...

  20. Further Evaluation of the Psychometric Properties of the Acceptance and Action Questionnaire-II

    ERIC Educational Resources Information Center

    Fledderus, Martine; Oude Voshaar, Martijn A. H.; ten Klooster, Peter M.; Bohlmeijer, Ernst T.

    2012-01-01

    The Acceptance and Action Questionnaire-II (AAQ-II) is a self-report measure designed to assess experiential avoidance as conceptualized in acceptance and commitment therapy (ACT). The current study is the first to evaluate the psychometric properties of the AAQ-II in a large sample of adults (N = 376) with mild to moderate levels of depression…

  1. 10 CFR 603.540 - Acceptability of fully depreciated real property or equipment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Acceptability of fully depreciated real property or equipment. 603.540 Section 603.540 Energy DEPARTMENT OF ENERGY (CONTINUED) ASSISTANCE REGULATIONS TECHNOLOGY INVESTMENT AGREEMENTS Pre-Award Business Evaluation Cost Sharing § 603.540 Acceptability of fully...

  2. 10 CFR 603.550 - Acceptability of intellectual property.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... property (e.g., copyrighted material, including software) as cost sharing because: (1) It is difficult to... the contribution. For example, a for-profit firm may offer the use of commercially available software for which there is an established license fee for use of the product. The costs of the development...

  3. 10 CFR 603.550 - Acceptability of intellectual property.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... property (e.g., copyrighted material, including software) as cost sharing because: (1) It is difficult to... the contribution. For example, a for-profit firm may offer the use of commercially available software... the software would not be a reasonable basis for valuing its use....

  4. 10 CFR 603.550 - Acceptability of intellectual property.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... property (e.g., copyrighted material, including software) as cost sharing because: (1) It is difficult to... the contribution. For example, a for-profit firm may offer the use of commercially available software... the software would not be a reasonable basis for valuing its use....

  5. 10 CFR 603.550 - Acceptability of intellectual property.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... property (e.g., copyrighted material, including software) as cost sharing because: (1) It is difficult to... the contribution. For example, a for-profit firm may offer the use of commercially available software... the software would not be a reasonable basis for valuing its use....

  6. Effect of chain extension on rheology and tensile properties of PHB and PHB-PLA blends

    NASA Astrophysics Data System (ADS)

    Bousfield, Glenn

    blend continued to degrade, and the PLLA did not in these cases significantly increase complex viscosity. By contrast, the 25/75 PHB/PLLA blend had a complex viscosity equal to the neat PLLA blend, and both of the blends remained stable. All five blends were also produced with 1% Joncryl to observe the effect of Joncryl on the blends. In the 50/50 blend and the blends in which PLLA was the major component, complex viscosity increased by at least an order of magnitude, while in the 75/25 PHB/PLLA blend and the neat PHB blend, the effect of Joncryl was to increase complex viscosity only by a factor of 2. The effect of blending and of Joncryl on PHB-PLA blends was further investigated through uniaxial tensile stress testing of compression moulded samples of the blends, neat and with 1% Joncryl. The results showed an increase in tensile stress at yield and tensile strain at break for blends with the addition of Joncryl, although Young's modulus was somewhat diminished for these blends. In conclusion, chain extenders were not effective in reversing the effect of thermomechanical degradation, possibly because they do not change the resistance to bond rotation in PHB chains, or because they are not reactive with acrylates, although the exact cause has not been determined.

  7. Tensile Properties and Microstructure of Inconel 718 Fabricated with Electron Beam Freeform Fabrication (EBF(sup 3))

    NASA Technical Reports Server (NTRS)

    Bird, R. Keith; Hibberd, Joshua

    2009-01-01

    Electron beam freeform fabrication (EBF3) direct metal deposition processing was used to fabricate two Inconel 718 single-bead-width wall builds and one multiple-bead-width block build. Specimens were machined to evaluate microstructure and room temperature tensile properties. The tensile strength and yield strength of the as-deposited material from the wall and block builds were greater than those for conventional Inconel 718 castings but were less than those for conventional cold-rolled sheet. Ductility levels for the EBF3 material were similar to those for conventionally-processed sheet and castings. An unexpected result was that the modulus of the EBF3-deposited Inconel 718 was significantly lower than that of the conventional material. This low modulus may be associated with a preferred crystallographic orientation resultant from the deposition and rapid solidification process. A heat treatment with a high solution treatment temperature resulted in a recrystallized microstructure and an increased modulus. However, the modulus was not increased to the level that is expected for Inconel 718.

  8. Microstructure and tensile properties of Fe-40 at. pct Al alloys with C, Zr, Hf, and B additions

    NASA Technical Reports Server (NTRS)

    Gaydosh, D. J.; Draper, S. L.; Nathal, M. V.

    1989-01-01

    The influence of small additions of C, Zr, and Hf, alone or in combination with B, on the microstructure and tensile behavior of substoichiometric FeAl was investigated. Tensile properties were determined from 300 to 1100 K on powder which was consolidated by hot extrusion. All materials possessed some ductility at room temperature, although ternary additions generally reduced ductility compared to the binary alloy. Adding B to the C- and Zr-containing alloys changed the fracture mode from intergranular to transgranular and restored the ductility to approximately 5 percent elongation. Additions of Zr and Hf increased strength up to about 900 K. Fe6Al6Zr and Fe6Al6Hf precipitates, both with identical body-centered tetragonal structures, were identified as the principal second phase in these alloys. Strength decreased steadily as temperature increased above 700 K, as diffusion-assisted mechanisms became operative. Although all alloys had similar strengths at 1100 K, Hf additions significantly improved high-temperature ductility by suppressing cavitation.

  9. Effect of processing parameter and filler content on tensile properties of multi-walled carbon nanotubes reinforced polylactic acid nanocomposite

    NASA Astrophysics Data System (ADS)

    Ali, Adilah Mat; Ahmad, Sahrim Hj.

    2013-05-01

    Polymer nanocomposite of multi-walled carbon nanotubes (MWCNT) nanoparticles incorporated with polylactic acid (PLA) and liquid natural rubber (LNR) as compatibilizer were prepared via melt blending method using the Haake Rheomix internal mixer. In order to obtain the optimal processing parameter, the nanocomposite with 89 wt % of PLA was blended with 10 wt % of LNR and 1 wt % of MWCNTs were mixed with various mixing parameter condition; mixing temperature, mixing speed and mixing time. The optimum processing parameter of the composites was obtained at temperature of 190°C, rotation speed of 90 rpm and mixing time of 14 min. Next, the effect of MWCNTs loading on the tensile properties of nanocomposites was investigated. The nanocomposites were melt blended using the optimal processing parameter with MWCNTs loading of 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 and 4 wt %. The result showed that the sample with 3.5 wt % of MWCNTs gave higher tensile strength and Young's modulus. The SEM micrographs confirmed the effect of good dispersion of MWCNTs and their interfacial bonding in PLA nanocomposites. However, the elongation at break decreased with increasing the percentage of MWCNTs.

  10. Effect of yttrium additions on the elevated-temperature tensile properties and hardness of an advanced iron-nickel-chromium LMFBR cladding and duct alloy

    SciTech Connect

    Song, M.H.

    1981-10-01

    The effect of the addition of yttrium on the elevated temperature tensile properties and hardness of an Fe-34% Ni-12% Cr candidate LMFBR cladding and duct alloy was investigated. Tensile tests were performed from room temperature to 800/sup 0/C in 100/sup 0/C steps at strain rates of 2.2 x 10/sup -3/ and 2.2 x 10/sup -4/ sec/sup -1/. Hardness tests were performed from room temperature to 850/sup 0/C in 50/sup 0/C steps. The addition of 0.1% yttrium decreased the yield stress and ultimate tensile stress in the test temperature range employed. Hardness also decreased over this test temperature range. In tensile tests, dynamic strain aging behavior occurred both for the undoped and doped alloy in the temperature range from 200 to 600/sup 0/C and 300 to 600/sup 0/C for the lower and higher strain rate, respectively.

  11. Tensile and Creep Property Characterization of Potential Brayton Cycle Impeller and Duct Materials

    NASA Technical Reports Server (NTRS)

    Gabb, Timothy P.; Gayda, John

    2006-01-01

    This paper represents a status report documenting the work on creep of superalloys performed under Project Prometheus. Cast superalloys have potential applications in space as impellers within closed-loop Brayton cycle nuclear power generation systems. Likewise wrought superalloys are good candidates for ducts and heat exchangers transporting the inert working gas in a Brayton-based power plant. Two cast superalloys, Mar-M247LC and IN792, and a NASA GRC powder metallurgy superalloy, LSHR, are being screened to compare their respective capabilities for impeller applications. Several wrought superalloys including Hastelloy X, (Haynes International, Inc., Kokomo, IN), Inconel 617, Inconel 740, Nimonic 263, and Incoloy MA956 (Special Metals Corporation, Huntington, WV) are also being screened to compare their capabilities for duct applications. These proposed applications would require sufficient strength and creep resistance for long term service at temperatures up to 1200 K, with service times to 100,000 h or more. Conventional tensile and creep tests were performed at temperatures up to 1200 K on specimens extracted from the materials. Initial microstructure evaluations were also undertaken.

  12. Effect of Annealing on Microstructure and Tensile Properties of 5052/AZ31/5052 Clad Sheets

    NASA Astrophysics Data System (ADS)

    Nie, Huihui; Liang, Wei; Chi, Chengzhong; Li, Xianrong; Fan, Haiwei; Yang, Fuqian

    2016-05-01

    Three-layered 5052Al/AZ31Mg/5052Al (5052/AZ31/5052) clad sheets were fabricated by four-pass rolling and annealed under different conditions. Under the optimal annealing condition, homogeneous and equiaxial grains with an average AZ31 grain size of 5.24 µm were obtained and the maximum values of ultimate tensile strength and elongation of the clad sheet reached 230 MPa and 18%, respectively. Electron backscatter diffraction analysis showed that the AZ31 layer had a typical rolling texture with its c-axis parallel to the normal direction. The fraction of low-angle grain boundaries in the 5052 layer was nearly four times more than that in the AZ31 layer because of different deformation extent and recrystallization driving forces. The textures of Al3Mg2 and Mg17Al12 were similar to that of 5052 because of the deformation coordination during the rolling and recrystallization process. The orientation relationship between Mg17Al12 and AZ31 seemed to be (110) Mg17Al12//(10-11) AZ31.

  13. Tensile anisotropy and creep properties of a Fe-14CrWTi ODS ferritic steel

    NASA Astrophysics Data System (ADS)

    Steckmeyer, A.; Rodrigo, Vargas Hideroa; Gentzbittel, J. M.; Rabeau, V.; Fournier, B.

    2012-07-01

    A Fe-14Cr oxide dispersion strengthened (ODS) ferritic steel is studied as a potential material for cladding tube application for the next generation of fast-breeder nuclear reactors. Tensile specimens machined out from a hot extruded round bar in three different orientations are used to evaluate the mechanical anisotropy of this steel for temperatures in the range 20-750 °C. Its anisotropy is discussed both in terms of mechanical strength and fracture mode. At high temperatures (HTs), above 500 °C, the longitudinal direction appears to be the most ductile and most resistant direction. Longitudinal creep tests between 650 °C and 900 °C were also carried out. They show this ODS steel has a high HT creep lifetime and a low creep failure strain. Intergranular cracks aligned along the loading axis were observed on fractured creep specimens. They reveal a particular weakness of prior particle boundaries and suggest to modify the elaboration process through mechanical alloying and hot extrusion.

  14. Tensile properties of vanadium alloys irradiated at <430{degrees}C

    SciTech Connect

    Chung, H.M.; Smith, D.L.

    1997-08-01

    Recent attention to vanadium alloys has focused on significant susceptibility to loss of work-hardening capability in irradiation experiments at <430{degrees}C. An evaluation of this phenomenon was conducted on V-Ti, V-Cr-Ti, and V-Ti-Si alloys irradiated in several conventional and helium-charging irradiation experiments in the FFTF-MOTA, HFIR, and EBR-II. Work hardening capability and uniform tensile elongation appear to vary strongly from alloy and heat to heat. A strong heat-to-heat variation has been observed in V-4Cr-4Ti alloys tested, i.e., a 500-kg heat (No. 832665), a 100-kg heat (VX-8), and a 30-kg heat (BL-47). The significant differences in susceptibility to loss of work-hardening capability from one heat to another are estimated to correspond to a difference of {approx}100{degrees}C or more in minimum allowable operating temperature (e.g., 450 versus 350{degrees}C).

  15. Microstructure evolution and tensile properties of Zr-2.5 wt.% Nb pressure tubes processed from billets with different microstructures

    SciTech Connect

    Kapoor, K.; Saratchandran, N.; Muralidharan, K.

    1999-02-01

    Pressurized heavy water reactors (PHWR) use zirconium-base alloys for their low neutron-absorption cross section, good mechanical strength, low irradiation creep, and high corrosion resistance in reactor atmospheres. Starting with identical ingots, billets having different microstructures were obtained by three different processing methods for fabrication of Zr-2.5 wt%Nb pressure tubes., The billets were further processed by hot extrusion and cold Pilger tube reducing to the finished product. Microstructural characterization was done at each stage of processing. The effects of the initial billet microstructure on the intermediate and final microstructure and mechanical property results were determined. It was found that the structure at each stage and the final mechanical properties depend strongly on the initial billet microstructure. The structure at the final stage consists of elongated alpha zirconium grains with a network of metastable beta zirconium phase. Some of this metastable phase transforms into stable beta niobium during thermomechanical processing. Billets with quenched structure resulted in less beta niobium at the final stage. The air cooled billets resulted in a large amount of beta niobium. The tensile properties, especially the percentage elongation, were found to vary for the different methods. Higher percentage elongation was observed for billets having quenched structure. Extrusion and forging did not produce any characteristic differences in the properties. The results were used to select a process flow sheet which yields the desired mechanical properties with suitable microstructure in the final product.

  16. Studies of Microtexture and Its Effect on Tensile and High-Cycle Fatigue Properties of Laser-Powder-Deposited INCONEL 718

    NASA Astrophysics Data System (ADS)

    Qi, Huan; Azer, Magdi; Deal, Andrew

    2012-11-01

    The current work studies the microstructure, texture, and mechanical properties of INCONEL 718 alloy (IN718) produced by laser direct metal deposition. The grain microstructure exhibits an alternative distribution of banded fine and coarse grain zones as a result of the rastering scanning pattern. The effects of the anisotropic crystallographic texture on the tensile and high-cycle fatigue (HCF) properties at room temperature are investigated. Tensile test results showed that the tensile strength of laser-deposited IN718 after direct aging or solution heat treatment is equivalent to the minimum-forged IN718 properties. The transverse direction (relative to the laser scanning direction) produces >10 pct stiffer modulus of elasticity but 3 to 6 pct less tensile strength compared to the longitudinal direction due to the preferential alignment of grains having <111> and <100> directions parallel to the tensile loading direction. Laser-deposited IN718 with good metallurgical integrity showed equivalent HCF properties compared to the direct-aged wrought IN718, which can be attributed to the banded grain size variation and cyclic change of inclining grain orientations resulted from alternating rastering deposition path.

  17. Studies on tensile properties and fracture behavior of Al-6Si-0.5Mg (-Cu or/and Ni) alloys at various strain rates

    NASA Astrophysics Data System (ADS)

    Hossain, A.; Gulshan, F.; Kurny, A. S. W.

    2016-07-01

    The aim of this paper is to evaluate the effects of various strain rates on the tensile properties of Al-6Si-0.5Mg cast alloys with Cu or/and Ni additions and to establish data on the stress-strain behavior of the alloys with applications in automotive engineering. Experimental alloys of the following composition were prepared by melt processing technique. Both microstructure and the mechanical properties were investigated. The uniaxial tension test was carried out at strain rates ranging from 10-4s-1 to 10-2s-1. Tensile strengths were found to increase with ageing temperature and the maximum being attained at peak age condition (1hr at 225°C). The additions of Cu or/and Ni resulted in an increase in tensile strength and 2wt% Cu content alloy (Al-6Si-0.5Mg-2Cu) showed maximum strength. Evaluation of tensile properties at three strain rates (10-4, 10-3 and 10-2s-1) showed that strain rates affected the tensile properties significantly. At higher strain rates the strength was better but ductility was poor.

  18. Metallurgical and tensile property analysis of several silicon carbide/titanium composite systems

    NASA Technical Reports Server (NTRS)

    Brewer, W. D.; Unnam, J.

    1983-01-01

    Several silicon-carbide fiber reinforced titanium matrix composite systems were investigated to determine composite degradation mechanisms and to develop techniques to minimize loss of mechanical properties during fabrication and in service. Emphasis was on interface control by fiber or matrix coatings. Fibers and matrix materials were sputter coated with various metals to determine the effects of the coatings on basic fiber properties, fiber-matrix interactions, and on composite properties. The effects of limited variations in fabrication temperature on composite properties were determined for composites consolidated by standard press-diffusion-bonding techniques.

  19. Effect of Specimen Diameter on Tensile Properties of Austenitic Stainless Steels in Liquid Hydrogen and Gaseous Helium at 20K

    NASA Astrophysics Data System (ADS)

    Fujii, H.; Ohmiya, S.; Shibata, K.; Ogata, T.

    2006-03-01

    Tensile tests using round bar type specimens of 3, 5 and 7 mm in diameter were conducted at 20K in liquid hydrogen and also in gaseous helium at the same temperature for three major austenitic stainless steels, JIS SUS304L, 316L and 316LN, extensively used for cryogenic applications including liquid hydrogen transportation and storage vessels. Stress-strain curves were considerably different between circumstances and also specimen diameter, resulting in differences of strength and ductility. In liquid hydrogen, serrated deformation appeared after considerable work hardening and more active in specimens with larger diameter. Meanwhile serrated deformation was observed from the early stage of plastic deformation in gaseous helium at 20 K and serration was more frequent in specimens with smaller diameter. The serrated deformation behaviors were numerically simulated for 304L steel with taking thermal properties such as thermal conductivity, specific heat, heat transfer from specimens to cryogenic media into account, and some agreement with the experiments was obtained.

  20. Tensile and impact properties of vanadium-base alloys irradiated at low temperatures in the ATR-A1 experiment

    SciTech Connect

    Tsai, H.; Nowicki, L.J.; Billone, M.C.; Chung, H.M.; Smith, D.L.

    1998-03-01

    Subsize tensile and Charpy specimens made from several V-(4-5)Cr-(4-5)Ti alloys were irradiated in the ATR-A1 experiment to study the effects of low-temperature irradiation on mechanical properties. These specimens were contained in lithium-bonded subcapsules and irradiated at temperatures between {approx}200 and 300 C. Peak neutron damage was {approx}4.7 dpa. Postirradiation testing of these specimens has begun. Preliminary results from a limited number of specimens indicate a significant loss of work-hardening capability and dynamic toughness due to the irradiation. These results are consistent with data from previous low-temperature neutron irradiation experiments on these alloys.

  1. Effect of Specimen Diameter on Tensile Properties of Austenitic Stainless Steels in Liquid Hydrogen and Gaseous Helium at 20K

    SciTech Connect

    Fujii, H.; Ohmiya, S.; Shibata, K.; Ogata, T.

    2006-03-31

    Tensile tests using round bar type specimens of 3, 5 and 7 mm in diameter were conducted at 20K in liquid hydrogen and also in gaseous helium at the same temperature for three major austenitic stainless steels, JIS SUS304L, 316L and 316LN, extensively used for cryogenic applications including liquid hydrogen transportation and storage vessels. Stress-strain curves were considerably different between circumstances and also specimen diameter, resulting in differences of strength and ductility. In liquid hydrogen, serrated deformation appeared after considerable work hardening and more active in specimens with larger diameter. Meanwhile serrated deformation was observed from the early stage of plastic deformation in gaseous helium at 20 K and serration was more frequent in specimens with smaller diameter. The serrated deformation behaviors were numerically simulated for 304L steel with taking thermal properties such as thermal conductivity, specific heat, heat transfer from specimens to cryogenic media into account, and some agreement with the experiments was obtained.

  2. Tensile properties of V-Cr-Ti alloys after exposure in oxygen-containing environments

    SciTech Connect

    Natesan, K.; Soppet, W.K.

    1998-03-01

    A systematic study was conducted to evaluate the oxidation kinetics of V-4Cr-4Ti (44 alloy) and V-5Cr-5Ti alloys (55 alloy) and to establish the role of oxygen ingress on the tensile behavior of the alloys at room temperature and at 500 C. The oxidation rate of the 44 alloy is slightly higher than that of the 55 alloy. The oxidation process followed parabolic kinetics. Maximum engineering stress for 55 alloy increased with an increase in oxidation time at 500 C. The maximum stress values for 55 alloy were higher at room temperature than ta 500 C for the same oxidation treatment. Maximum engineering stresses for 44 alloy were substantially lower than those for 55 alloy in the same oxidation {approx}500 h exposure in air at 500 C; the same values were 4.8 and 6.1%, respectively, at 500 C after {approx}2060 h oxidation in air at 500 C. Maximum engineering stress for 44 alloy at room temperature was 421.6--440.6 MPa after {approx}250 h exposure at 500 C in environments with a pO{sub 2} range of 1 {times} 10{sup {minus}6} to 760 torr. The corresponding uniform and total elongation values were 11--14.4% and 14.5--21.7%, respectively. Measurements of crack depths in various specimens showed that depth is independent of pO{sub 2} in the preexposure environment and was of 70--95 {micro}m after 250--275 h exposure at 500 C.

  3. Tensile properties of thin Au-Ni brazes between strong base materials

    SciTech Connect

    Tolle, M.C.; Kassner, M.E. )

    1991-12-01

    It has long been known that when relatively strong base materials are joined by thin, soft, interlayer metals such as with brazing or various solid state joining processes, the ultimate tensile strength (UTS) of the bond may be several factors higher than the UTS of the bulk, or unconstrained, interlayer metals. However, earlier work reported by the authors confirmed that delayed or creep'' failure of the bond may occur at stresses much less than the UTS. It was found that for thin silver interlayers, prepared by brazing and physical vapor deposition (PVD), joining elastically deforming base materials (i.e. no measurable plastic deformation occurs in the base metal at the applied stresses), the ambient (and near-ambient) temperature time to failure is controlled by the creep rate of the silver interlayer which is determined by the effective stress within the interlayer. The plastic deformation within the interlayer causes cavity nucleation which continues until the concentration of nuclei is sufficiently high to lead to instability and eventual failure. The delayed failure may be accelerated by base material creep resulting from the effective stress in the base material. Plastic deformation in the base metal causes corresponding deformation in the interlayer, and cavities nucleate as with elastic base metal case. The delayed failure phenomenon was confirmed by the authors only for silver interlayers; other compositions were not tested. In this study, maraging steel was joined with an Au-Ni braze alloy with 57.5 at. % Au and 42.5 at. % Ni. The microstructure is expected to be a refined two-phase (spinodal) alloy with higher strength than the PVD silver of our previous investigation.

  4. Tensile properties of thin Au-Ni brazes between strong base materials

    SciTech Connect

    Tolle, M.C.; Kassner, M.E.

    1991-12-01

    It has long been known that when relatively strong base materials are joined by thin, soft, interlayer metals such as with brazing or various solid state joining processes, the ultimate tensile strength (UTS) of the bond may be several factors higher than the UTS of the bulk, or unconstrained, interlayer metals. However, earlier work reported by the authors confirmed that delayed or ``creep`` failure of the bond may occur at stresses much less than the UTS. It was found that for thin silver interlayers, prepared by brazing and physical vapor deposition (PVD), joining elastically deforming base materials (i.e. no measurable plastic deformation occurs in the base metal at the applied stresses), the ambient (and near-ambient) temperature time to failure is controlled by the creep rate of the silver interlayer which is determined by the effective stress within the interlayer. The plastic deformation within the interlayer causes cavity nucleation which continues until the concentration of nuclei is sufficiently high to lead to instability and eventual failure. The delayed failure may be accelerated by base material creep resulting from the effective stress in the base material. Plastic deformation in the base metal causes corresponding deformation in the interlayer, and cavities nucleate as with elastic base metal case. The delayed failure phenomenon was confirmed by the authors only for silver interlayers; other compositions were not tested. In this study, maraging steel was joined with an Au-Ni braze alloy with 57.5 at. % Au and 42.5 at. % Ni. The microstructure is expected to be a refined two-phase (spinodal) alloy with higher strength than the PVD silver of our previous investigation.

  5. Tensile Properties and Integrity of Clean Room and Low-Modulus Disposable Nitrile Gloves: A Comparison of Two Dissimilar Glove Types

    PubMed Central

    Phalen, Robert N.; Wong, Weng kee

    2012-01-01

    Background: The selection of disposable nitrile exam gloves is complicated by (i) the availability of several types or formulations, (ii) product variability, and (iii) an inability of common quality control tests to detect small holes in the fingers. Differences in polymer formulation (e.g. filler and plasticizer/oil content) and tensile properties are expected to account for much of the observed variability in performance. Objectives: This study evaluated the tensile properties and integrity (leak failure rates) of two glove choices assumed to contain different amounts of plasticizers/oils. The primary aims were to determine if the tensile properties and integrity differed and if associations existed among these factors. Additional physical and chemical properties were evaluated. Methods: Six clean room and five low-modulus products were evaluated using the American Society for Testing and Materials Method D412 and a modified water-leak test to detect holes capable of passing a virus or chemical agent. Results: Significant differences in the leak failure rates and tensile properties existed between the two glove types (P ≤ 0.05). The clean room gloves were about three times more likely to have leak failures (chi-square; P = 0.001). No correlation was observed between leak failures and tensile properties. Solvent extract, an indication of added plasticizer/oil, was not associated with leak failures. However, gloves with a maximum modulus <4 MPa or area density (AD) <11 g cm−2 were about four times less likely to leak. Conclusions: On average, the low-modulus gloves were a better choice for protection against aqueous chemical or biological penetration. The observed variability between glove products indicated that glove selection cannot rely solely on glove type or manufacturer labeling. Measures of modulus and AD may aid in the selection process, in contrast with common measures of tensile strength and elongation at break. PMID:22201179

  6. Soft magnetic properties of nanocrystalline Fe73B7Si16Nb3Cu1 alloy after rapid heating under tensile stress.

    PubMed

    Nosenko, Anton; Mika, Taras; Rudenko, Olexandr; Yarmoshchuk, Yevhenii; Nosenko, Viktor

    2015-01-01

    Amorphous Fe73B7Si16Nb3Cu1 ribbon was crystallized rapidly by electric current heating under simultaneously applied tensile stress along the ribbon axis. As a result, strong transverse magnetic anisotropy was induced in the ribbon. Dynamic magnetic properties of the ribbons rapidly heated either under the tensile stress or without tensile stress were measured using toroidal cores. Optimal electric current heating regime that provides maximum improvement of the initial magnetic permeability and core loss was determined. Tensile stress increase from 0 to 180 MPa was shown to result in the decrease of the initial magnetic permeability down to 400 and core loss at frequencies from 0.4 to 200 kHz. Comparative analysis of magnetic properties of the cut core (with non-magnetic gap) and the cores heated under tensile stress was carried out. The magnetic properties of the latter cores are advantageous for manufacturing the reactors and linear chokes of switch-mode power supplies. PMID:25852427

  7. Soft magnetic properties of nanocrystalline Fe73B7Si16Nb3Cu1 alloy after rapid heating under tensile stress

    NASA Astrophysics Data System (ADS)

    Nosenko, Anton; Mika, Taras; Rudenko, Olexandr; Yarmoshchuk, Yevhenii; Nosenko, Viktor

    2015-03-01

    Amorphous Fe73B7Si16Nb3Cu1 ribbon was crystallized rapidly by electric current heating under simultaneously applied tensile stress along the ribbon axis. As a result, strong transverse magnetic anisotropy was induced in the ribbon. Dynamic magnetic properties of the ribbons rapidly heated either under the tensile stress or without tensile stress were measured using toroidal cores. Optimal electric current heating regime that provides maximum improvement of the initial magnetic permeability and core loss was determined. Tensile stress increase from 0 to 180 MPa was shown to result in the decrease of the initial magnetic permeability down to 400 and core loss at frequencies from 0.4 to 200 kHz. Comparative analysis of magnetic properties of the cut core (with non-magnetic gap) and the cores heated under tensile stress was carried out. The magnetic properties of the latter cores are advantageous for manufacturing the reactors and linear chokes of switch-mode power supplies.

  8. 10 CFR 603.540 - Acceptability of fully depreciated real property or equipment.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Acceptability of fully depreciated real property or... real property or equipment. The contracting officer should limit the value of any contribution of a... time of the negotiations; (c) The effect of any increased maintenance charges or decreased...

  9. 49 CFR 1544.201 - Acceptance and screening of individuals and accessible property.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Acceptance and screening of individuals and... screening of individuals and accessible property. (a) Preventing or deterring the carriage of any explosive...) Screening of individuals and accessible property. Except as provided in its security program, each...

  10. On the complexity of the relationship between microstructure and tensile properties in cast aluminum

    NASA Astrophysics Data System (ADS)

    Bjurenstedt, Anton; Seifeddine, Salem; Jarfors, Anders E. W.

    2015-03-01

    The relationship between microstructure and mechanical properties in cast aluminum alloys is complex and is strongly affected by the casting process conditions and melt handling practices. The aim of the current work is to understand the critical interactions between material microstructure, mechanical properties and process quality in the development of high performance aluminum alloys. The mechanical properties were investigated and correlated with microstructural features such as porosity, Fe-rich particles, secondary dendrite arm spacing (SDAS) and Si-particle length. The correlation with process quality measures such as bifilm index, density index and sludge factor (SF) were also investigated. The Si-particle lengths were found to explain variation in material strength and ductility which factors such as the bifilm index and porosity could not.

  11. Effect of native oxide layers on copper thin-film tensile properties: A reactive molecular dynamics study

    SciTech Connect

    Skarlinski, Michael D.; Quesnel, David J.

    2015-12-21

    Metal-oxide layers are likely to be present on metallic nano-structures due to either environmental exposure during use, or high temperature processing techniques such as annealing. It is well known that nano-structured metals have vastly different mechanical properties from bulk metals; however, difficulties in modeling the transition between metallic and ionic bonding have prevented the computational investigation of the effects of oxide surface layers. Newly developed charge-optimized many body [Liang et al., Mater. Sci. Eng., R 74, 255 (2013)] potentials are used to perform fully reactive molecular dynamics simulations which elucidate the effects that metal-oxide layers have on the mechanical properties of a copper thin-film. Simulated tensile tests are performed on thin-films while using different strain-rates, temperatures, and oxide thicknesses to evaluate changes in yield stress, modulus, and failure mechanisms. Findings indicate that copper-thin film mechanical properties are strongly affected by native oxide layers. The formed oxide layers have an amorphous structure with lower Cu-O bond-densities than bulk CuO, and a mixture of Cu{sub 2}O and CuO charge character. It is found that oxidation will cause modifications to the strain response of the elastic modulii, producing a stiffened modulii at low temperatures (<75 K) and low strain values (<5%), and a softened modulii at higher temperatures. While under strain, structural reorganization within the oxide layers facilitates brittle yielding through nucleation of defects across the oxide/metal interface. The oxide-free copper thin-film yielding mechanism is found to be a tensile-axis reorientation and grain creation. The oxide layers change the observed yielding mechanism, allowing for the inner copper thin-film to sustain an FCC-to-BCC transition during yielding. The mechanical properties are fit to a thermodynamic model based on classical nucleation theory. The fit implies that the oxidation of the

  12. Crystalline and tensile properties of carbon nanotube and graphene reinforced polyamide 12 fibers

    NASA Astrophysics Data System (ADS)

    Chatterjee, S.; Nüesch, F. A.; Chu, B. T. T.

    2013-02-01

    The influence of carbon nanotubes (CNTs) and graphene nanoplatelets (GnPs) on the structure and mechanical properties of polyamide 12 (PA12) fibers was investigated. As seen from wide-angle X-ray diffraction analysis the crystallinity index increases with incorporation of nanofillers due to nucleation effects. Marked improvement was noted for mechanical properties of the composites with increase in elastic modulus, yield stress and strength of the fibers. The most significant improvement of a factor of 4 could be observed for elastic modulus with the inclusion of 0.5 wt.% GnP. A comparative study was made between the fibers reinforced with CNTs and GnPs.

  13. Solar Effects on Tensile and Optical Properties of Hubble Space Telescope Silver-Teflon(Registered Trademark) Insulation

    NASA Technical Reports Server (NTRS)

    deGroh, Kim, K.; Dever, Joyce A.; Snyder, Aaron; Kaminski, Sharon; McCarthy, Catherine E.; Rapoport, Alison L.; Rucker, Rochelle N.

    2006-01-01

    A section of the retrieved Hubble Space Telescope (HST) solar array drive arm (SADA) multilayer insulation (MLI), which experienced 8.25 years of space exposure, was analyzed for environmental durability of the top layer of silver-Teflon (DuPont) fluorinated ethylene propylene (Ag-FEP). Because the SADA MLI had solar and anti-solar facing surfaces and was exposed to the space environment for a long duration, it provided a unique opportunity to study solar effects on the environmental degradation of Ag-FEP, a commonly used spacecraft thermal control material. Data obtained included tensile properties, solar absorptance, surface morphology and chemistry. The solar facing surface was found to be extremely embrittled and contained numerous through-thickness cracks. Tensile testing indicated that the solar facing surface lost 60% of its mechanical strength and 90% of its elasticity while the anti-solar facing surface had ductility similar to pristine FEP. The solar absorptance of both the solar facing surface (0.155 plus or minus 0.032) and the anti-solar facing surface (0.208 plus or minus 0.012) were found to be greater than pristine Ag-FEP (0.074). Solar facing and anti-solar facing surfaces were microscopically textured, and locations of isolated contamination were present on the anti-solar surface resulting in increased localized texturing. Yet, the overall texture was significantly more pronounced on the solar facing surface indicating a synergistic effect of combined solar exposure and increased heating with atomic oxygen erosion. The results indicate a very strong dependence of degradation, particularly embrittlement, upon solar exposure with orbital thermal cycling having a significant effect.

  14. Gas bubble retention and its effect on waste properties: Retention mechanisms, viscosity, and tensile and shear strengths

    SciTech Connect

    Gauglitz, P.A.; Rassat, S.D.; Powell, M.R.

    1995-08-01

    Several of the underground nuclear storage tanks at Hanford have been placed on a flammable gas watch list, because the waste is either known or suspected to generate, store, and episodically release flammable gases. Because retention and episodic release of flammable gases from these tanks containing radioactive waste slurries are critical safety concerns, Pacific Northwest Laboratory (PNL) is studying physical mechanisms and waste properties that contribute to the episodic gas release from these storage tanks. This study is being conducted for Westinghouse Hanford Company as part of the PNL Flammable Gas project. Previous investigations have concluded that gas bubbles are retained by the slurry or sludge that has settled at the bottom of the tanks; however, the mechanisms responsible for the retention of these bubbles are not well understood. Understanding the rheological behavior of the waste, particularly of the settled sludge, is critical to characterizing the tendency of the waste to retain gas bubbles and the dynamics of how these bubbles are released from the waste. The presence of gas bubbles is expected to affect the rheology of the sludge, specifically its viscosity and tensile and shear strengths, but essentially no literature data are available to assess the effect of bubbles. The objectives of this study were to conduct experiments and develop theories to understand better how bubbles are retained by slurries and sludges, to measure the effect of gas bubbles on the viscosity of simulated slurries, and to measure the effect of gas bubbles on the tensile and shear strengths of simulated slurries and sludges. In addition to accomplishing these objectives, this study developed correlations, based on the new experimental data, that can be used in large-scale computations of waste tank physical phenomena.

  15. Tensile and solubility properties of calcium caseinate films cross-linked with genipin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Edible films made from dairy proteins have the potential to improve food quality and safety and reduce petrochemical-based packaging because of their excellent grease, aroma and oxygen barrier properties. However, most are soluble in water and sensitive to humidity which limits their use in many app...

  16. Tensile properties and deformation mechanisms in two-phase titanium aluminide sheet material

    SciTech Connect

    Appel, F.; Wagner, R.; Clemens, H.; Glatz, W.

    1997-12-31

    The mechanical properties of two-phase TiAl sheets with different compositions and microstructures were investigated over the temperature range 25--1,000 C. The microprocesses of plasticity were characterized by electron microscope observations. Particular emphasis has been paid to the mechanisms governing the deformation behavior at elevated temperatures which are relevant for the fabrication and engineering applications of structural components.

  17. Influence of Sludge Particles on the Tensile Properties of Die-Cast Secondary Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Ferraro, Stefano; Timelli, Giulio

    2015-04-01

    The effects of sludge intermetallic particles on the mechanical properties of a secondary AlSi9Cu3(Fe) die-casting alloy have been studied. Different alloys have been produced by systematically varying the Fe, Mn, and Cr contents within the composition tolerance limits of the standard EN AC-46000 alloy. The microstructure shows primary α-Al x (Fe,Mn,Cr) y Si z sludge particles, with polyhedral and star-like morphologies, although the presence of primary β-Al5FeSi phase is also observed at the highest Fe:Mn ratio. The volume fraction of primary compounds increases as the Fe, Mn, and Cr contents increase and this can be accurately predicts from the Sludge Factor by a linear relationship. The sludge amount seems to not influence the size and the content of porosity in the die-cast material. Furthermore, the sludge factor is not a reliable parameter to describe the mechanical properties of the die-cast AlSi9Cu3(Fe) alloy, because this value does not consider the mutual interaction between the elements. In the analyzed range of composition, the design of experiment methodology and the analysis of variance have been used in order to develop a semi-empirical model that accurately predicts the mechanical properties of the die-cast AlSi9Cu3(Fe) alloys as function of Fe, Mn, and Cr concentrations.

  18. Microstructural Developments and Tensile Properties of Lean Fe-Mn-Al-C Lightweight Steels

    NASA Astrophysics Data System (ADS)

    Sohn, S. S.; Lee, S.; Lee, B.-J.; Kwak, J.-H.

    2014-09-01

    Concepts of Fe-Al-Mn-C-based lightweight steels are fairly simple, but primary metallurgical issues are complicated. In this study, recent studies on lean-composition lightweight steels were reviewed, summarized, and emphasized by their microstructural development and mechanical properties. The lightweight steels containing a low-density element of Al were designed by thermodynamic calculation and were manufactured by conventional industrial processes. Their microstructures consisted of various secondary phases as κ-carbide, martensite, and austenite in the ferrite matrix according to manufacturing and annealing procedures. The solidification microstructure containing segregations of C, Mn, and Al produced a banded structure during the hot rolling. The (ferrite + austenite) duplex microstructure was formed after the annealing, and the austenite was retained at room temperature. It was because the thermal stability of austenite nucleated from fine κ-carbide was quite high due to fine grain size of austenite. Because these lightweight steels have outstanding properties of strength and ductility as well as reduced density, they give a promise for automotive applications requiring excellent properties.

  19. Effect of fiber treatments on tensile and thermal properties of starch/ethylene vinyl alcohol copolymers/coir biocomposites.

    PubMed

    Rosa, Morsyleide F; Chiou, Bor-sen; Medeiros, Eliton S; Wood, Delilah F; Williams, Tina G; Mattoso, Luiz H C; Orts, William J; Imam, Syed H

    2009-11-01

    Coir fibers received three treatments, namely washing with water, alkali treatment (mercerization) and bleaching. Treated fibers were incorporated in starch/ethylene vinyl alcohol copolymers (EVOH) blends. Mechanical and thermal properties of starch/EVOH/coir biocomposites were evaluated. Fiber morphology and the fiber/matrix interface were further characterized by scanning electron microscopy (SEM). All treatments produced surface modifications and improved the thermal stability of the fibers and consequently of the composites. The best results were obtained for mercerized fibers where the tensile strength was increased by about 53% as compared to the composites with untreated fibers, and about 33.3% as compared to the composites without fibers. The mercerization improved fiber-matrix adhesion, allowing an efficient stress transfer from the matrix to the fibers. The increased adhesion between fiber and matrix was also observed by SEM. Treatment with water also improved values of Young's modulus which were increased by about 75% as compared to the blends without the fibers. Thus, starch/EVOH blends reinforced with the treated fibers exhibited superior properties than neat starch/EVOH. PMID:19560341

  20. Magnetic properties of Fe-based ribbons with controlled permeability prepared by continuous pulse annealing under tensile stress

    NASA Astrophysics Data System (ADS)

    Takagi, Kotaro; Yanai, Takeshi; Takahashi, Ken-ichiro; Nakano, Masaki; Fukunaga, Hirotoshi; Yoshizawa, Yoshihito

    2009-04-01

    An amorphous Fe73.5Cu1Nb3Si15.5B7 ribbon was pulse annealed continuously under tensile stress by being passed through in an infrared furnace switched on and off repeatedly for preparation of a nanocrystallized toroidal core with controlled permeability. Optimization of the duty ratio D(=Ton/T) of the furnace enabled us to obtain ribbons with low Hc(<10 A/m) and completely developed anisotropy under a high moving velocity of the ribbon, 50 cm/min. ac magnetic properties of a toroidal core, which is made from the pulse-annealed ribbon, at Bm=0.1 T were measured in the frequency range of 0.1-1 MHz. The loss of the prepared core at f =0.1 MHz is 0.50 J/m3, which is lower than those for a gapped ferrite, sendust powder, and amorphous powder core. The relative permeability of approximately 330 was constant up to 1 MHz. These results suggest that the continuous stress annealing by pulse annealing method is one of the hopeful methods for preparation of a long ribbon with excellent magnetic properties.

  1. Effect of fission neutron irradiation on the tensile and electrical properties of copper and copper alloys

    SciTech Connect

    Fabritsiev, S.A.; Zinkle, S.J.; Rowcliffe, A.F.

    1995-04-01

    The objective of this study is to evaluate the properties of several copper alloys following fission reactor irradiation at ITER-relevant temperatures of 80 to 200{degrees}C. This study provides some of the data needed for the ITER research and development Task T213. These low temperature irradiations caused significant radiation hardening and a dramatic decrease in the work hardening ability of copper and copper alloys. The uniform elongation was higher at 200{degree}C compared to 100{degree}C, but still remained below 1% for most of the copper alloys.

  2. Tensile properties of cast and mechanically alloyed FeAl with high boron content

    SciTech Connect

    Kim, M.H.; Kwun, S.I.

    1996-08-01

    The FeAl with B2 structure has been considered as a potential structural material for use at elevated temperatures and severe environment. Two major problems with this polycrystalline aluminide are its brittleness through cleavage or grain boundary failure at ambient temperature and rapid strength drop at high temperatures above 750K. In order to expand the use of iron aluminide, these two problems must be overcome. Making a grain size small might be one of the effective ways as the stress distribution is more homogeneous throughout the material. Another method to increase the ductility of iron rich FeAl seems to add small amount of boron. Webb reported that the optimum B content for ambient temperature ductility enhancement was approximately 12 wppm in FeAl(40at%Al). With these points in mind, the authors have tried to modify room and high temperature mechanical properties of FeAl by mechanical alloying. The mechanical alloying is a unique process in that it is an entirely solid state process, permitting fine distribution of insoluble phases and fine grain size material. This paper compares the mechanical properties of the cast and the mechanically alloyed FeAl with B as much as 0.3wt%. The highest B content added in iron rich FeAl was reported to be 0.2wt% up to now.

  3. Effect of Austempering Conditions on the Microstructure and Tensile Properties of Low Alloyed Sintered Steel

    NASA Astrophysics Data System (ADS)

    Campos, M.; Sicre-Artalejo, J.; Muñoz, J. J.; Torralba, J. M.

    2010-07-01

    Because of the combination of strength and toughness, much interest has been focused on austempered sintered low-alloyed steels. Implementation of this treatment for powder metal components has been limited by interaction between the open porosity of the material and the cooling fluid. This work discusses the influence of different austempering environments and parameters on the microstructure and, as a consequence, on the final properties. The sintered steels selected are based on two different prealloyed powders, Fe-1.5Cr-0.2Mo and Fe-1.5Mo, with the addition of 0.6 wt pct graphite. Green samples with medium density (7.3 g/cm3) were sintered at 1393 and 1523 K (1120 and 1250 °C) to ensure a decrease in open porosity. The austempering treatment process requires austenitizing at 1133 K (860 °C) for 2 hours followed by quenching in different baths at 563 K (290 °C). The final strength and ductility are dependent upon the relative amounts of ferrite, pearlite, and bainite phases present in the austempered steel. Discussion of the experimental results compares the as-sintered and the austempered observations as well as the relationship between mechanical properties and the phases present in the final microstructures.

  4. Tensile Properties and Microstructural Characterization of Hi-Nicalon SiC/RBSN Composites

    NASA Technical Reports Server (NTRS)

    Bhatt, Ramakrishna T.

    1998-01-01

    The room temperature physical and mechanical properties of silicon carbide fiber-reinforced reaction-bonded silicon nitride matrix composites (SiC/RBSN) were measured, and the composite microstructure was analyzed. The composites consist of nearly 24 vol% of aligned Hi-Nicalon SiC fiber yarns in a approx. 30 vo1% porous silicon nitride matrix. The fiber yarns were coated by chemical vapor deposition with a 0.8 micron layer of boron nitride (BN) followed by a 0.2 micron layer of SiC. In the as-fabricated condition, both 1-D and 2-D composites exhibited high strength and graceful failure, and showed improved properties when compared with unreinforced matrix of comparable density. No indication of reaction between the SiC fiber and BN coating was noticed, but the outer SiC layer reacted locally with the nitridation enhancing additive in the RBSN matrix. A comparison is made between the predicted and measured values of matrix cracking strength.

  5. Material and structural tensile properties of the human medial patello-femoral ligament.

    PubMed

    Criscenti, G; De Maria, C; Sebastiani, E; Tei, M; Placella, G; Speziali, A; Vozzi, G; Cerulli, G

    2016-02-01

    The medial patellofemoral ligament (MPFL) is considered the most important passive patellar stabilizer and acts 50-60% of the force of the medial soft-tissue which restrains the lateralization of the patella between 0° and 30°. In this work, 24 human knees have been tested to evaluate the material properties of MPFL and to determine the structural behavior of femur-MPFL-Patella complex (FMPC). Particular attention was given to maintain the anatomical orientation between the patella and MPFL and to the evaluation of the elongation during the mechanical tests. The ultimate stress of the isolated ligament was 16±11MPa, the ultimate strain was 24.3±6.8%, the Young׳s Modulus was 116±95MPa and the strain energy density was 2.97±1.69MPa. The ultimate load of the whole structure, FMPC, was 145±68N, the ultimate elongation was 9.5±2.9mm, the linear stiffness was 42.5±10.2N/mm and the absorbed energy was 818.8±440.7Nmm. The evaluation of material and structural properties of MPFL is fundamental to understand its contribution as stabilizer and for the selection of repair and reconstruction methods. PMID:26454357

  6. Tensile Properties and Microstructural Characterization of Hi-Nicalon SiC/RBSN Composites

    NASA Technical Reports Server (NTRS)

    Bhatt, Ramakrishna T.

    1998-01-01

    The room temperature physical and mechanical properties of silicon carbide fiber-reinforced reaction-bonded silicon nitride matrix composites (SiC/RBSN) were measured, and the composite microstructure was analyzed. The composites consist of nearly 24 vol% of aligned Hi-Nicalon SiC fiber yarns in a approx. 30 vol% porous silicon nitride matrix. The fiber yarns were coated by chemical vapor deposition with a 0.8 mm layer of boron nitride (BN) followed by a 0.2 mm layer of SiC. In the as-fabricated condition, both 1-D and 2-D composites exhibited high strength and graceful failure, and showed improved properties w en compared with unreinforced matrix of comparable density. No indication of reaction between the SiC fiber and BN coating was noticed, but the outer SiC layer reacted locally with the nitridation enhancing additive in the RBSN matrix. A comparison is made between the predicted and measured values of matrix cracking strength.

  7. Electrospun polycaprolactone matrices with tensile properties suitable for soft tissue engineering.

    PubMed

    Elamparithi, Anuradha; Punnoose, Alan M; Kuruvilla, Sarah; Ravi, Maddaly; Rao, Suresh; Paul, Solomon F D

    2016-05-01

    The extracellular environment is a complex network of functional and structural components that impart chemical and mechanical stimuli that affect cellular function and fate. Cell differentiation on three dimensional scaffolds is also determined by the modulus of the substrate. Electrospun PCL nanofibers, which mimic the extra cellular matrix, have been developed with a wide variety of solvents and their combinations. The various studies have revealed that the solvents used influence the physical and mechanical properties, resulting in scaffolds with Young's modulus in the range of 1.8-15.4 MPa, more suitable for engineering of hard tissue like bone. The current study describes the use of benign binary solvent-generated fibrous scaffolds with a Young's modulus of 36.05 ± 13.08 kPa, which is almost 50 times lower than that of scaffolds derived from the commonly used solvents, characterized with myoblast, which can be further explored for applications in muscle and soft tissue engineering. PMID:25619755

  8. Effects of aminopropyltriethoxysilane (γ-APS) on tensile properties and morphology of polypropylene (PP), recycle acrylonitrile butadiene rubber (NBRr) and sugarcane bagasse (SCB) composites

    NASA Astrophysics Data System (ADS)

    Santiagoo, Ragunathan; Omar, Latifah; Zainal, Mustaffa; Ting, Sam Sung; Ismail, Hanafi

    2015-07-01

    The performance of sugarcane baggase (SCB) treated with γ-APS filled polypropylene (PP)/recycled acrylonitrile butadiene rubber (NBRr) biocomposites were investigated. The composites with different filler loading ranging from 5 to 30 wt % were prepared using heated two roll mill by melt mixing at temperature of 180 °C. Tensile properties of the PP/NBRr/SCB composites which is tensile strength, Young Modulus and elongation at break were investigated. Increasing of treated SCB filler loading in PP/NBRr/SCB composites have increased the Young modulus however decreased the tensile strength and elongation at break of the PP/NBRr/SCB composites. From the results, γ-APS treated SCB composites shown higher tensile strength and Young Modulus but lower elongation at break when compared to the untreated SCB composites. This is due to the stronger bonding between γ-APS treated SCB with PP/NBRr matrices. These findings was supported by micrograph pictures from morphological study. SCB filler treated with γ-APS has improved the adhesion as well as gave strong interfacial bonding between SCB filler and PP/NBRr matrices which results in good tensile strength of PP/NBRr/SCB composites.

  9. 77 to 1200 K tensile properties of several wrought superalloys after long-term 1093 K heat treatment in air and vacuum

    NASA Astrophysics Data System (ADS)

    Whittenberger, J. D.

    1994-02-01

    The 77 to 1200 K tensile properties of approximately 1.3 mm thick wrought sheet Co-base Haynes alloy 188 and Ni-base Haynes alloy 230 and Inconel 617 have been measured after heat treatment in air and vacuum for periods up to 22,500 h at 1093 K. Significant changes in structure were produced by prior exposures, including precipitation of second phases and, in the case of heat treatment in air, oxide scale and surface-connected grain boundary pits/oxides, as deep as 50 to 70 µm, in all three superalloys. Due to the geometry of the experiment, the vacuum-exposed samples were protected from loss of volatile elements by evaporation; hence, such specimens were simply given 1093 K anneals in an innocuous environment, which produced very little surface attack. Compared to the properties of as-received alloys, prior exposure tended to reduce both the yield strength and ultimate tensile strength, with the greatest reductions at 77 and 298 K. The most dramatic effect of heat treatment was found in the low-temperature residual tensile elongation, where decreases from 40 to 5% at 77 K were found. Ductility is the only property that was found to have a consistent dependency on environment, with air exposure always yielding less tensile elongation than vacuum exposure.

  10. 77 to 1,200 K tensile properties of several wrought superalloys after long-term 1,093 K heat treatments in air and vacuum

    SciTech Connect

    Whittenberger, J.D. . Lewis Research Center)

    1994-02-01

    The 77 to 1,200 K tensile properties of approximately 1.3 mm thick wrought sheet Co-base Haynes alloy 188 and Ni-base Haynes alloy 230 and Inconel 617 have been measured after heat treatment in air and vacuum for periods up to 22,500 h at 1,093 K. Significant changes in structure were produced by prior exposures, including precipitation of second phases and, in the case of heat treatment in air, oxide scale and surface-connected grain boundary pits/oxides, as deep as 50 to 70 [mu]m, in all three superalloys. Due to the geometry of the experiment, the vacuum-exposed samples were protected from loss of volatile elements by evaporation; hence, such specimens were simply given 1,093 K anneals in an innocuous environment, which produced very little surface attack. Compared to the properties of as-received alloys, prior exposure tended to reduce both the yield strength and ultimate tensile strength, with the greatest reductions at 77 and 298 K. The most dramatic effect of heat treatment was found in the low-temperature residual tensile elongation, where decreases from 40 to 5% at 77 K were found. Ductility is the only property that was found to have a consistent dependency on environment, with air exposure always yielding less tensile elongation than vacuum exposure.

  11. The Influence of Ni and V Trace Elements on High-Temperature Tensile Properties and Aging of A356 Aluminum Foundry Alloy

    NASA Astrophysics Data System (ADS)

    di Giovanni, Maria Teresa; Cerri, Emanuela; Casari, Daniele; Merlin, Mattia; Arnberg, Lars; Garagnani, Gian Luca

    2016-05-01

    High-temperature tensile properties of unmodified A356 alloy with and without the addition of Ni or V in traces (600 and 1000 ppm of Ni and V, respectively) were investigated by analyzing samples obtained from sand and permanent mold castings in the as-cast and T6 heat-treated conditions. Tensile tests were performed at 508 K (235 °C) at a crosshead speed of 1 mm/min. In addition, samples were subjected to artificial aging at 508 K (235 °C) for different times, and corresponding hardness curves were plotted. Microstructures and fracture surfaces, analyzed by FEG-SEM equipped with energy dispersive X-ray spectroscopy, showed that neither Ni nor V addition had a detrimental effect on high-temperature tensile properties. Aging curves showed a strong loss of hardness affecting the T6 class between 30-min and 1-h exposure time. After 6-h aging, no evidence of aging treatment persisted on hardness of the tested material. Hardness values did not reveal any significant difference between the reference alloy and the Ni- and V-containing alloys in both casting conditions, in complete analogy with the tensile properties. Unmodified eutectic silicon particles provided inhomogeneity in the α-Al matrix and acted as the principal source of stress concentration leading to fracture.

  12. Tensile Creep Properties of the 50Au-50Cu Braze Alloy

    SciTech Connect

    Stephens, J.J.

    1999-05-28

    The 50Au-50CU (wt.%) alloy is a solid-solution strengthened braze alloy used extensively in conventional, hermetic metal/ceramic brazing applications where low vapor pressure is a requirement. Typical metal/ceramic base materials would be KovarTM alloy and metallized and Ni-plated 94% alumina ceramic. The elevated temperature mechanical properties are important for permitting FEA evaluation of residual stresses in metal/ceramic brazes given specific geometries and braze cooldown profiles. For material with an atomic composition of 76.084 at.% CL 23.916 Au (i.e., on the Cu-rich side of Cu3Au) that was annealed for 2 hr. at 750°C and water quenched a Garofalo sinh equation was found to adequately characterize the minimum strain rate data over the temperature mnge 450-850°C. At lower temperatures (250 arid 350°C), a conventional power law equation was found to characterize the data. For samples held long periods of time at 375°C (96 hrs.) and slowly cooled to room temperature, a slight strengthening reaction was observed: with the stress necessary to reach the same strain rate increasing by about 15% above the baseline annealed and quenched data. X-ray diffiction indicates that the 96 hr at 375°C + slow cool condition does indeed order. The microhardness of the ordered samples indicates a value of 94.5 VHN, compared to 93.7 VHN for the baseline annealed and quenched (disordered FCC) samples. From a brazing perspective, the relative sluggishness of this ordering reaction does not appear to pose a problem for braze joints cooled at reasonable rates following brazing.

  13. Tensile properties from room temperature to 1315 C of tungsten-lined tantalum-alloy (T-111) tubing fabricated by hot isostatic pressing

    NASA Technical Reports Server (NTRS)

    Buzzard, R. J.; Metroka, R. R.

    1974-01-01

    The effects were studied of a thin tungsten liner on the tensile properties of T-111 tubing considered for fuel cladding in a space power nuclear reactor concept. The results indicate that the metallurgically bonded liner had no appreciable effects on the properties of the T-111 tubing. A hot isostatic pressing method used to apply the liners is described along with a means for overcoming the possible embrittling effects of hydrogen contamination.

  14. Effect of carbon content on high temperature tensile properties of Fe{sub 3}Al based intermetallic alloys

    SciTech Connect

    Baligidad, R.G.; Prakash, U.; Radhakrishna, A.; Rao, V.R.; Rao, P.K.; Ballal, N.B.

    1997-01-01

    Ordered intermetallic alloys based on the iron aluminide Fe{sub 3}Al are being considered for high temperature structural applications. Though these alloys exhibit poor room temperature ductility and low fracture toughness, significant improvement in these respects can be achieved by alloying addition and process control. Most of the reported literature is on compositions with very low (<0.01 wt.%) carbon contents because carbon is known to embrittle these alloys causing significant reduction in ductility. However, no reasons have been ascribed to this loss in ductility. Recently the authors have reported that addition of carbon in the range of 0.14 to 0.50 wt.% significantly increases the room temperature strength of Fe-16 wt.% (28 at.%)Al alloys. These alloys also exhibited good room temperature by the interstitial carbon, as well as precipitation hardening due to the presence of Fe{sub 3}AlC precipitates. Here, the authors report elevated temperature tensile properties of these alloys.

  15. Influence of humidity on the room temperature tensile properties of Fe[sub 3]Al-based alloys

    SciTech Connect

    Moret, M.; Jongenburger, C.P. ); Zhuang, L. )

    1994-11-01

    Iron aluminides are of potential interest in view of their good corrosion resistance at elevated temperatures, especially in atmospheres with high sulfur and low oxygen partial pressures. However, the ductility of these alloys at room temperature is relatively low. Liu et al. reported that Fe[sub 3]Al was quite ductile when tested in a dry oxygen atmosphere and in a vacuum at room temperature. The lowest ductility was obtained when samples were tested in H[sub 2]O vapor. It has been suggested that the embrittlement of Fe[sub 3]Al is due to atomic hydrogen arising from a reaction between water vapor and aluminum atoms at crack tips. The hydrogen atoms diffuse into the metal and concentrate on critical trap sites, such as grain boundaries and dislocations, thereby promoting crack propagation. In this paper, the tensile properties of a binary and alloyed iron aluminide will be reported as a function of the temperature, strain rate and relative humidity of the air. The influence of humidity on fracture surfaces of the aluminides will be shown.

  16. Charpy toughness and tensile properties of a neutron irradiated stainless steel submerged-arc weld cladding overlay

    SciTech Connect

    Corwin, W.R.; Berggren, R.G.; Nanstad, R.K.

    1984-01-01

    The possibility of stainless steel cladding increasing the resistance of an operating nuclear reactor pressure vessel to extension of surface flaws is highly dependent upon the irradiated properties of the cladding. Therefore, weld overlay cladding irradiated at temperatures and fluences relevant to power reactor operation was examined. The cladding was applied to a pressure vessel steel plate by the submerged-arc, single-wire, oscillating electrode method. Three layers of cladding were applied to provide a cladding thickness adequate for fabrication of test specimens. The first layer was type 309, and the upper two layers were type 308 stainless steel. There was considerable dilution of the type 309 in the first layer of cladding as a result of excessive melting of the base plate. Specimens for the irradiation study were taken from near the base plate/cladding interface and also from the upper layers of cladding. Charpy V-notch and tensile specimens were irradiated at 288/sup 0/C to neutron fluences of 2 x 10/sup 23/ n/m/sup 2/ (E > 1 MeV). When irradiated, both types 308 and 309 cladding showed a 5 to 40% increase in yield strength accompanied by a slight increase in ductility in the temperature range from 25 to 288/sup 0/C. All cladding exhibited ductile-to-brittle transition behavior during impact testing.

  17. Effect of test temperature and strain rate on the tensile properties of high-strength, high-conductivity copper alloys

    SciTech Connect

    Zinkle, S.J.; Eatherly, W.S.

    1997-04-01

    The unirradiated tensile properties of wrought GlidCop AL25 (ITER grade zero, IGO) solutionized and aged CuCrZr, and cold-worked and aged and solutionized and aged Hycon 3HP{trademark} CuNiBe have been measured over the temperature range of 20-500{degrees}C at strain rates between 4 x 10{sup {minus}4} s{sup {minus}1} and 0.06 s{sup {minus}1}. The measured room temperature electrical conductivity ranged from 64 to 90% IACS for the different alloys. All of the alloys were relatively insensitive to strain rate at room temperature, but the strain rate sensitivity of GlidCop Al25 increased significantly with increasing temperature. The CuNiBe alloys exhibited the best combination of high strength and high conductivity at room temperature. The strength of CuNiBe decreased slowly with increasing temperature. However, the ductility of CuNiBe decreased rapidly with increasing temperature due to localized deformation near grain boundaries, making these alloy heats unsuitable for typical structural applications above 300{degrees}C. The strength and uniform elongation of GlidCop Al25 decreased significantly with increasing temperature at a strain rate of 1 x 10{sup {minus}3} s{sup {minus}1}, whereas the total elongation was independent of test temperature. The strength and ductility of CuCrZr decreased slowly with increasing temperature.

  18. Characterization of Tensile Properties, Limiting Strains, and Deep Drawing Behavior of AA5754-H22 Sheet at Elevated Temperature

    NASA Astrophysics Data System (ADS)

    Panicker, Sudhy S.; Singh, Har Govind; Panda, Sushanta Kumar; Dashwood, Richard

    2015-11-01

    Automotive industries are very much interested in characterization of formability improvement of aluminum alloys at elevated temperatures before designing tools, heating systems, and processing sequences for fabrication of auto-body panels by warm forming technology. In this study, tensile tests of AA5754-H22 aluminum alloy were carried out at five different temperatures and three different strain rates to investigate the deformation behavior correlating with Cowper-Symonds constitutive equation. Laboratory scale warm forming facilities were designed and fabricated to perform limiting dome height and deep drawing tests to evaluate forming limit strains and drawability of sheet metal at different tool temperatures. The forming limit strain and dome height improved significantly when both the die and punch were heated to 200 °C. Remarkable improvement in deep drawn cup depth was observed when die and punch temperatures were maintained at 200 and 30 °C, respectively, producing a non-isothermal temperature gradient of approximately 93 °C across the blank from flange to center. The forming behavior at different isothermal and non-isothermal conditions were predicted successfully using a thermo-mechanical FE model incorporating temperature-dependent properties in Barlat-89 yield criterion coupled with Cowper-Symonds hardening model, and the thinning/failure location in deformed cups were validated implementing the experimental limiting strains as damage model.

  19. An open-end burst test method to obtain uniaxial hoop tensile properties of fuel cladding in a hot cell

    NASA Astrophysics Data System (ADS)

    Nakatsuka, Masafumi; Aita, Makoto; Sakamoto, Kan; Higuchi, Toru

    2013-03-01

    The hoop stress-hoop strain relationship of fuel cladding is one of the essential input parameters for safety analysis of fuel rods. The three objectives of this paper were: to propose a burst test method for open-end tube specimens with the uniaxial hoop stress condition; to develop the necessary in-cell high temperature open-end burst (OEB) techniques to implement the method; and to determine the optimum specimen length for the proposed OEB test method. Silicone oil was selected as the pressurization medium, and it was sealed inside the specimens not by welding but by O-rings so that no axial tensile stress was induced in the specimens. The specimens with combined end plugs and O-rings were successfully assembled by manipulators in a hot cell, and a high temperature (⩽350 °C), high pressure (⩽100 MPa) seal was achieved. The optimum specimen length was determined by using ductile and embrittled tubes with various lengths of 30-60 mm and was found to be around 45 mm for typical BWR fuel rods. During the OEB test, internal pressure and diametral expansion were monitored to obtain the basic mechanical performance properties of the fuel cladding such as yield stress, ultimate strength, as well as the true hoop stress-hoop strain curve.

  20. Effect of neutron irradiation on tensile properties of materials for pressure vessel internals of WWER type reactors

    NASA Astrophysics Data System (ADS)

    Sorokin, A. A.; Margolin, B. Z.; Kursevich, I. P.; Minkin, A. J.; Neustroev, V. S.

    2014-01-01

    Tensile properties of austenitic stainless steels used for pressure vessel internals of WWER type reactors (18Cr-10Ni-Ti steel and its weld metal) in the initial and irradiated conditions were investigated. Based on the presented original investigations and generalization of the available experimental data the dependences of yield strength and ultimate strength on a neutron damage dose up to 108 dpa, irradiation temperature range 320-450 °C and test temperature range 20-450 °C were obtained. The method of determination of the stress-strain curve parameters was proposed which does not require uniform elongation of a specimen as an input parameter. The dependences was proposed allowing one to calculate the stress-strain curve parameters for 18Cr-10Ni-Ti steel and its weld metal for different test temperatures, different irradiation temperatures and doses. The dependences were obtained to describe the fracture strain decrease under irradiation at a temperature range 320-340 °C when irradiation swelling is absent.

  1. 49 CFR 1544.201 - Acceptance and screening of individuals and accessible property.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 9 2012-10-01 2012-10-01 false Acceptance and screening of individuals and accessible property. 1544.201 Section 1544.201 Transportation Other Regulations Relating to Transportation (Continued) TRANSPORTATION SECURITY ADMINISTRATION, DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION...

  2. 49 CFR 1546.201 - Acceptance and screening of individuals and accessible property.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 9 2014-10-01 2014-10-01 false Acceptance and screening of individuals and accessible property. 1546.201 Section 1546.201 Transportation Other Regulations Relating to Transportation (Continued) TRANSPORTATION SECURITY ADMINISTRATION, DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION SECURITY FOREIGN AIR CARRIER SECURITY Operations...

  3. 49 CFR 1544.201 - Acceptance and screening of individuals and accessible property.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 9 2014-10-01 2014-10-01 false Acceptance and screening of individuals and accessible property. 1544.201 Section 1544.201 Transportation Other Regulations Relating to Transportation (Continued) TRANSPORTATION SECURITY ADMINISTRATION, DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION SECURITY AIRCRAFT OPERATOR SECURITY: AIR...

  4. 49 CFR 1544.201 - Acceptance and screening of individuals and accessible property.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 9 2011-10-01 2011-10-01 false Acceptance and screening of individuals and accessible property. 1544.201 Section 1544.201 Transportation Other Regulations Relating to Transportation (Continued) TRANSPORTATION SECURITY ADMINISTRATION, DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION...

  5. 49 CFR 1546.201 - Acceptance and screening of individuals and accessible property.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 9 2011-10-01 2011-10-01 false Acceptance and screening of individuals and accessible property. 1546.201 Section 1546.201 Transportation Other Regulations Relating to Transportation (Continued) TRANSPORTATION SECURITY ADMINISTRATION, DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION...

  6. 49 CFR 1544.201 - Acceptance and screening of individuals and accessible property.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 9 2013-10-01 2013-10-01 false Acceptance and screening of individuals and accessible property. 1544.201 Section 1544.201 Transportation Other Regulations Relating to Transportation (Continued) TRANSPORTATION SECURITY ADMINISTRATION, DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION...

  7. 10 CFR 603.540 - Acceptability of fully depreciated real property or equipment.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Acceptability of fully depreciated real property or equipment. 603.540 Section 603.540 Energy DEPARTMENT OF ENERGY (CONTINUED) ASSISTANCE REGULATIONS TECHNOLOGY... officer must consider: (a) The original cost of the asset; (b) Its estimated remaining useful life at...

  8. Determination of the elastic properties of rabbit vocal fold tissue using uniaxial tensile testing and a tailored finite element model.

    PubMed

    Latifi, Neda; Miri, Amir K; Mongeau, Luc

    2014-11-01

    The aim of the present study was to quantify the effects of the specimen shape on the accuracy of mechanical properties determined from a shape-specific model generation strategy. Digital images of five rabbit vocal folds (VFs) in their initial undeformed conditions were used to build corresponding specific solid models. The displacement field of the VFs under uniaxial tensile test was then measured over the visible portion of the surface using digital image correlation. A three-dimensional finite element model was built, using ABAQUS, for each solid model, while imposing measured boundary conditions. An inverse-problem method was used, assuming a homogeneous isotropic linear elastic constitutive model. Unknown elastic properties were identified iteratively through an error minimization technique between simulated and measured force-time data. The longitudinal elastic moduli of the five rabbit VFs were calculated and compared to values from a simple analytical method and those obtained by approximating the cross-section as elliptical. The use of shape-specific models significantly reduced the standard deviation of the Young׳s moduli of the tested specimens. However, a non-parametric statistical analysis test, i.e., the Friedman test, yielded no statistically significant differences between the shape-specific method and the elliptic cylindrical finite element model. Considering the required procedures to reconstruct the shape-specific finite element model for each tissue specimen, it might be expedient to use the simpler method when large numbers of tissue specimens are to be compared regarding their Young׳s moduli. PMID:25173237

  9. Carbon nanotube modification using gum arabic and its effect on the dispersion and tensile properties of carbon nanotubes/epoxy nanocomposites.

    PubMed

    Kim, Man Tae; Park, Ho Seok; Hui, David; Rhee, Kyong Yop

    2011-08-01

    In this study, the effects of a MWCNT treatment on the dispersion of MWCNTs in aqueous solution and the tensile properties of MWCNT/epoxy nanocomposites were investigated. MWCNTs were treated using acid and gum arabic, and MWCNT/epoxy nanocomposites were fabricated with 0.3 wt.% unmodified, oxidized and gum-treated MWCNTs. The dispersion states of the unmodified, oxidized, and Gum-treated MWCNTs were characterized in distilled water. The tensile strengths and elastic modulus of the three nanocomposites were determined and compared. The results indicated that the gum treatment produced better dispersion of the MWCNTs in distilled water and that gum-treated MWCNT/epoxy nanocomposites had a better tensile strength and elastic modulus than did the unmodified and acid-treated MWCNT/epoxy nanocomposites. Scanning electron microscope examination of the fracture surface showed that the improved tensile properties of the gum-treated MWCNT/epoxy nanocomposites were attributed to the improved dispersion of MWCNTs in the epoxy and to interfacial bonding between nanotubes and the epoxy matrix. PMID:22103198

  10. Analysis of elevated-temperature tensile and creep properties of normalized and tempered 2 1/4 Cr-1 Mo steel

    SciTech Connect

    Booker, M.K.; Booker, B.L.P.; Swindeman, R.W.

    1982-01-01

    Tensile and creep data were collected for normalized and tempered 2 1/4 Cr-1 Mo steel from American, Japanese, British, French, and German sources. These included creep data obtained at temperatures from 427 to 600/sup 0/C (800 to 1112/sup 0/F) and tensile data from room temperature to 550/sup 0/C (1022/sup 0/F). Properties examined included yield strength, ultimate tensile strength, 10/sup 5/-h creep-rupture strength, and 10/sup -5/%/h creep strength. These are the properties used in setting allowable stresses for Section VIII, Division 1, of the ASME Boiler and Pressure Vessel Code. The data were analyzed by using lot-centered regression approaches that yielded expressions for the variations in the above properties with loading condition, as well as accounting for lot-to-lot variations in properties. No indications were found of systematic differences in any of the properties examined for data from the different countries. However, the estimated allowable stresses from this investigation fell up to 10% below those currently given for this material in the ASME Code. Several possible reasons were cited for the differences, and we concluded that our results are not overly conservative. On the other hand, there is no direct evidence that the current code allowable stresses are insufficiently conservative, since those stresses rely on factors (such as service experience) other than experimental data.

  11. Influence of thermo-mechanical treatment on the tensile properties of a modified 14Cr-15Ni stainless steel

    NASA Astrophysics Data System (ADS)

    Vijayanand, V. D.; Laha, K.; Parameswaran, P.; Nandagopal, M.; Panneer Selvi, S.; Mathew, M. D.

    2014-10-01

    The titanium modified 14Cr-15Ni austenitic stainless steel is used as clad and wrapper material for fast breeder nuclear reactor. Thermo-mechanical treatments consisting of solution annealing at two different temperatures of 1273 and 1373 K followed by cold-work and thermal ageing have been imparted to the steel to tailor its microstructure for enhancing strength. Tensile tests have been carried out on the thermo-mechanically treated steel at nominal strain rate of 1.6 × 10-4 s-1 over a temperature range of 298-1073 K. The yield stress and the ultimate tensile strength of the steel increased with increase in solution treatment temperature and this has been attributed to the fine and higher density of Ti(C,N) precipitate. Tensile flow behaviour of the steel has been analysed using Ludwigson and Voce constitutive equations. The steel heat treated at higher solution temperature exhibited earlier onset of cross slip during tensile deformation. The rate of recovery at higher test temperatures was also influenced by variations in solution heat treatment temperature. In addition, dynamic recrystallization during tensile deformation at higher temperatures was profound for steel solution heat-treated at lower temperature. The differences in flow behaviour and softening mechanisms during tensile testing of the steel after different heat treated conditions have been attributed to the nature of Ti(C,N) precipitation.

  12. Analysis of elevated-temperature tensile and creep properties of normalized and tempered 2-1/4 Cr-1 Mo steel

    SciTech Connect

    Booker, M.K.; Booker, B.L.P.; Swindeman, R.W.

    1982-01-01

    The ferritic 2-1/4 Cr-1 Mo steel is an important construction material for elevated-temperature applications worldwide. It is of particular interest for coal conversion pressure vessels. Tensile and creep data are presented for normalized and tempered 2-1/4 Cr-1 Mo steel from American, Japanese, British, French, and German sources. These include creep data obtained at temperatures from 427 to 600/sup 0/C (800 to 1112/sup 0/F) and tensile data from room temperature to 550/sup 0/C (1022/sup 0/F). Properties examined included yield strength, ultimate tensile strength, 10/sup 5/-h creep-rupture strength, and 10/sup -5/%/h creep strength. These are the properties used in setting allowable stresses for Secton VIII, Division 1, of the ASME Boiler and Pressure Vessel Code. The data were analyzed by using lot-centered regression approaches that yielded expressions for the variations in the above properties with loading condition, as well as accounting for lot-to-lot variations in properties.

  13. Physico-chemical properties and acceptability of yam flour substituted with soy flour.

    PubMed

    Akingbala, J O; Oguntimein, G B; Sobande, A O

    1995-07-01

    Yam flour was substituted 10, 20 and 40% with defatted and full fat soy flour. The effect of the substitution on the proximate composition, swelling power, solubility, water binding capacity and Brabender visco amylograph cooking properties of the yam flour and acceptability of the cooked paste (amala), were evaluated. Protein contents of the mixtures were 23.0 and 25.5% on substituting 40% full-and defatted soy flours for yam flour, ash and crude fibre contents increased while carbohydrate content, swelling power, Brabender paste viscosities decreased with increase in soy flour substitution of yam flour. Colour, texture, taste and overall acceptability of pastes (amala) from the mixed flours were rated lower than that of yam flour. Up to 10% defatted and 20% full fat soy flour substitution for yam flour was acceptable for amala. PMID:8719741

  14. Tensile Testing: A Simple Introduction

    ERIC Educational Resources Information Center

    Carr, Martin

    2006-01-01

    Tensile testing may be used to decide, say, which steel to use in various constructions. Analogous testing can be done simply in the classroom using plasticine and helps to introduce pupils to the various properties studied in materials science.

  15. Tensile properties of haynes alloy 230 and inconel 617 after long exposures to LiF-22CaF2 and vacuum at 1093 K

    NASA Astrophysics Data System (ADS)

    Whittenberger, J. D.

    1994-12-01

    As a part of a study of a space-based thermal energy storage system utilizing the latent heat of fusion of the eutectic salt LiF-20CaF2 (mole%), the two wrought Ni-base superalloys Haynes alloy 230 and Inconel 617 were subjected to molten salt, its vapor, and vacuum for periods as long as 10,000 h at 1093 K. Following exposure, the microstructures were characterized, and samples from each superalloy were tensile tested between 77 and 1200 K. Neither the structure nor mechanical properties revealed evidence for additional degradation due to exposures to the salt. Although some loss in tensile properties was noted, particularly at 77 K, this reduction could be ascribed to the influence of simple aging at 1093 K.

  16. Effect of small additions of silicon, iron, and aluminum on the room-temperature tensile properties of high-purity uranium

    SciTech Connect

    Ludwig, R.L.

    1983-11-14

    Eleven binary and ternary alloys of uranium and very low concentrations of iron, silicon, and aluminum were prepared and tested for room-temperature tensile properties after various heat treatments. A yield strength approximately double that of high-purity derby uranium was obtained from a U-400 ppM Si-200 ppM Fe alloy after beta solution treatment and alpha aging. Higher silicon plus iron alloy contents resulted in increased yield strength, but showed an unacceptable loss of ductility.

  17. Mechanical properties of Bi2223 filaments extracted from multifilamentary tape evaluated by the single-fibre tensile test

    NASA Astrophysics Data System (ADS)

    Sugano, Michinaka; Osamura, Kozo; Hojo, Masaki

    2003-05-01

    The Young's modulus and the tensile fracture strength of Bi2223 filaments extracted from multifilamentary tape have been evaluated using the single-fibre tensile test; they are estimated to be 106 GPa and 45 MPa, respectively. The distribution of the fracture strength can be analysed using the Weibull distribution function. It was found that the observed scatter of strength is very large compared with other superconducting filaments such as NbTi and Nb3Al. The Young's modulus was nearly identical with the estimated values based on the rule of mixture from the unload/reload modulus.

  18. A Comparative Evaluation of the Effect of Low Cycle Fatigue and Creep-Fatigue Interaction on Surface Morphology and Tensile Properties of 316L(N) Stainless Steel

    NASA Astrophysics Data System (ADS)

    Mariappan, K.; Shankar, Vani; Sandhya, R.; Bhaduri, A. K.; Laha, Kinkar

    2016-04-01

    In the present work, the deformation and damage evolution in 316L(N) stainless steel during low cycle fatigue (LCF) and creep-fatigue interaction (CFI) loadings have been compared by evaluating the residual tensile properties. Towards this, LCF and CFI experiments were carried out at constant strain amplitude of ±0.6 pct, strain rate of 3 × 10-3 s-1 and temperature of 873 K (600 °C). During CFI tests, 30 minutes hold period was introduced at peak tensile strain. Experiments were interrupted up to various levels of fatigue life viz. 5, 10, 30, 50, and 60 pct of the total fatigue life ( N f) under both LCF and CFI conditions. The specimens subjected to interrupted fatigue loadings were subsequently monotonically strained at the same strain rate and temperature up to fracture. Optical and scanning electron microscopy and profilometry were conducted on the untested and tested samples to elucidate the damage evolution during the fatigue cycling under both LCF and CFI conditions. The yield strength (YS) increased sharply with the progress of fatigue damage and attained saturation within 10 pct of N f under LCF condition. On the contrary, under CFI loading condition, the YS continuously increased up to 50 pct of N f, with a sharp increase of YS up to 5 pct of N f followed by a more gradual increase up to 50 pct of N f. The difference in the evolution of remnant tensile properties was correlated with the synergistic effects of the underlying deformation and damage processes such as cyclic hardening/softening, oxidation, and creep. The evolution of tensile properties with prior fatigue damage has been correlated with the change in surface roughness and other surface features estimated by surface replica technique and fractography.

  19. Influence of Prior Fatigue Damage on Tensile Properties of 316L(N) Stainless Steel and Modified 9Cr-1Mo Steel

    NASA Astrophysics Data System (ADS)

    Mariappan, K.; Shankar, Vani; Sandhya, R.; Mathew, M. D.; Bhaduri, A. K.

    2015-02-01

    In the current study, the effect of prior low-cycle fatigue (LCF) damage on the tensile properties of 316L(N) stainless steel (SS) and modified 9Cr-1Mo steel were systematically investigated. The LCF tests were interrupted at 5, 10, 30, and 50 pct of the total fatigue life followed by tensile tests on the same specimens at the same strain rate (3 × 10-3 s-1) and temperatures of 300 K, 823 K, and 873 K (27 °C, 550 °C, and 600 °C). Prior strain cycling at elevated temperatures had remarkable effect on the tensile properties of both cyclically hardening and cyclically softening materials. An exponential relationship between the yield stress and the amount of pre-strain cycles is obtained for both the materials. The initial drastic change in the yield strength values up to 10 pct of fatigue life may be due to the microstructural changes that lead to hardening or softening in 316L(N) SS and modified 9Cr-1Mo steel, respectively. Saturation in the yield strength values beyond 10 pct of fatigue life has practical importance for remnant fatigue life assessment. Evolution of fatigue damage in both the 316L(N) SS and modified 9Cr-1Mo steel was analyzed using the surface replica technique.

  20. Effect of ferrite transformation on the tensile and stress corrosion properties of type 316 L stainless steel weld metal thermally aged at 873 K

    NASA Astrophysics Data System (ADS)

    Shaikh, H.; Khatak, H. S.; Seshadri, S. K.; Gnanamoorthy, J. B.; Rodriguez, P.

    1995-07-01

    This article deals with the effect of the microstructural changes, due to transformation of delta ferrite, on the associated variations that take place in the tensile and stress corrosion properties of type 316 L stainless steel weld deposits when subjected to postweld heat treatment at 873 K for prolonged periods (up to 2000 hours). On aging for short durations (up to 20 hours), carbide/ carbonitride was the dominant transformation product, whereas sigma phase was dominant at longer aging times. The changes in the tensile and stress corrosion behavior of the aged weld metal have been attributed to the two competitive processes of matrix softening and hardening. Yield strength (YS) was found to depend predominantly on matrix softening only, while sig-nificant changes in the ultimate tensile strength (UTS) and the work-hardening exponent, n, occurred due to matrix hardening. Ductility and stress corrosion properties were considerably affected by both factors. Fractographic observations on the weld metal tested for stress-corrosion cracking (SCC) indicated a combination of transgranular cracking of the austenite and interface cracking.

  1. Effect of flaxseed flour incorporation on the physical properties and consumer acceptability of cereal bars.

    PubMed

    Khouryieh, H; Aramouni, F

    2013-12-01

    Extensive research has revealed numerous nutritional and health benefits of flaxseed due primarily to its nutrients content. The objective of this study was to evaluate the effect of flaxseed flour addition on the physical and sensory characteristics of cereal bars. Four formulations of the flaxseed cereal bars were prepared by partially replacing oats with flaxseed flour added at levels of 0 (control), 6%, 12% and 18%. There were no significant differences (p > 0.05) in water activity, moisture and firmness values between the flaxseed bars and control. Flaxseed addition significantly (p < 0.05) decreased lightness and increased redness of the bars. There were no significant differences (p > 0.05) between the 12% flax cereal bars and the control with respect to sensory attributes and overall acceptability. The overall acceptability for both 12% flax bars and the control was in between 'like moderately' and 'like slightly' on the 9-point hedonic scale. The overall acceptability was most highly correlated with flavor acceptability for both control (r = 0.80) and 12% flax (r = 0.82) cereal bars. Flaxseed bars provided 12% dietary fiber of the daily recommended value. These results indicated that flaxseed flour incorporation up to 12% substantially enhanced the nutritional qualities of the cereal bars without affecting their sensory and quality properties. PMID:23733813

  2. Development of India-specific RAFM steel through optimization of tungsten and tantalum contents for better combination of impact, tensile, low cycle fatigue and creep properties

    NASA Astrophysics Data System (ADS)

    Laha, K.; Saroja, S.; Moitra, A.; Sandhya, R.; Mathew, M. D.; Jayakumar, T.; Rajendra Kumar, E.

    2013-08-01

    Effects of tungsten and tantalum contents on impact, tensile, low cycle fatigue and creep properties of Reduced Activation Ferritic-Martensitic (RAFM) steel were studied to develop India-specific RAFM steel. Four heats of the steel have been melted with tungsten and tantalum contents in the ranges 1-2 wt.% and 0.06-0.14 wt.% respectively. Increase in tungsten content increased the ductile-to-brittle transition temperature (DBTT), low cycle fatigue and creep strength of the steel, whereas the tensile strength was not changed significantly. Increase in tantalum content increased the DBTT and low cycle fatigue strength of the steel whereas the tensile and creep strength decreased. Detailed TEM investigations revealed enhanced microstructural stability of the steel against creep exposure on tungsten addition. The RAFM steel having 1.4 wt.% tungsten with 0.06 wt.% tantalum was found to possess optimum combination of impact, tensile, low cycle fatigue and creep properties and is considered for Indian-specific RAFM steel. Low temperature impact energy of the RAFM steel is quite sensitive to the contents of tungsten and tantalum. The DBTT increased with both the tungsten and tantalum contents. Tungsten and tantalum contents in the investigated ranges had no appreciable effect on the tensile properties of the RAFM steel. Low cycle fatigue life of the RAFM steel increased with the increase in tungsten and tantalum contents. The softening rate with cyclic exposure was lowest for tungsten content of 1.4 wt.%, further increase in tungsten led to an increase in softening rate. Creep deformation and rupture strength of the RAFM steel were found to be quite sensitive to the tungsten and tantalum contents. Creep strength of the steel increased with increase in tungsten content and decreased with increase in tantalum content. Based on the study, the chemical composition of India-specific RAFM steel has been established as 9Cr-1.4W-0.06Ta-V, having optimum combination of strength and

  3. Tensile Properties of Nano AL2O3 Particulate-Reinforced Aluminum Matrix Composites by Mechanical Alloying and Hot Extrusion

    NASA Astrophysics Data System (ADS)

    Mehdinia, M.; Jenabali Jahromi, S. A.

    The powder of the micro Al and variant volume fractions of nano Al2O3 were milled by a high energy planetary ball-mill. By milling, a homogenous distribution of nano Al2O3 particles in the metal matrix were developed. Then the milled powder was cold compressed and sintered at 545°C for one hr. The mold and the sintered sample hold in a furnace until the temperature reached 545°C. Then the hot 27mm diameter sample was extruded to 6mm diameter. From the extruded specimens, tensile, hardness and microstructure of the prepared specimens were determined. By these tests the effect of milling time, the percent of nano-particles and the microstructure were evaluated. The hardness and tensile behaviors of aluminum matrix composites reinforced with nano Al2O3 particulate have been found to increase remarkably with the volume fraction of the reinforcement.

  4. Influence of the - phase separation on the tensile properties of Fe-base ODS PM 2000 alloy

    SciTech Connect

    Capdevila, C.; Miller, Michael K; Toda, I; Chao, J.

    2010-01-01

    The yield and ultimate tensile strengths of an ultrafine grained, oxide dispersion strengthened (ODS) PM 2000 alloy increased during aging at 475 C. Atom probe tomography and X-ray diffraction analysis revealed that the decrease in lattice parameter and the increases in the yield and ultimate tensile strengths were correlated with phase separation into Fe-rich {alpha} and Cr-enriched {alpha}{prime} phases. The lattice misfit between the emerging {alpha} and {alpha}{prime} domains and the resulting elastic strain, and the increment of the elastic modulus with aging time due to the corresponding decrease of lattice parameter during {alpha}-{alpha}{prime} phase separation, can be regarded as the main causes of hardening.

  5. Elevated temperature tensile properties of P9 steel towards ferritic steel wrapper development for sodium cooled fast reactors

    NASA Astrophysics Data System (ADS)

    Choudhary, B. K.; Mathew, M. D.; Isaac Samuel, E.; Christopher, J.; Jayakumar, T.

    2013-11-01

    Tensile deformation and fracture behaviour of the three developmental heats of P9 steel for wrapper applications containing varying silicon in the range 0.24-0.60% have been examined in the temperature range 300-873 K. Yield and ultimate tensile strengths in all the three heats exhibited gradual decrease with increase in temperature from room to intermediate temperatures followed by rapid decrease at high temperatures. A gradual decrease in ductility to a minimum at intermediate temperatures followed by an increase at high temperatures has been observed. The fracture mode remained transgranular ductile. The steel displayed signatures of dynamic strain ageing at intermediate temperatures and dominance of recovery at high temperatures. No significant difference in the strength and ductility values was observed for varying silicon in the range 0.24-0.60% in P9 steel. P9 steel for wrapper application displayed strength and ductility values comparable to those reported in the literature.

  6. Effect of Test Specimen Shape and Size on Interlaminar Tensile Properties of Advanced Carbon-Carbon Composites

    NASA Technical Reports Server (NTRS)

    Vaughn, Wallace L.

    2015-01-01

    The interlaminar tensile strength of 1000-tow T-300 fiber ACC-6 carbon-carbon composites was measured using the method of bonding the coupons to adherends at room temperature. The size, 0.70 to 1.963 inches maximum width or radius, and shape, round or square, of the test coupons were varied to determine if the test method was sensitive to these variables. Sixteen total variations were investigated and the results modeled.

  7. Plant material features responsible for bamboo's excellent mechanical performance: a comparison of tensile properties of bamboo and spruce at the tissue, fibre and cell wall levels

    PubMed Central

    Wang, Xiaoqing; Keplinger, Tobias; Gierlinger, Notburga; Burgert, Ingo

    2014-01-01

    Background and Aims Bamboo is well known for its fast growth and excellent mechanical performance, but the underlying relationships between its structure and properties are only partially known. Since it lacks secondary thickening, bamboo cannot use adaptive growth in the same way as a tree would in order to modify the geometry of the stem and increase its moment of inertia to cope with bending stresses caused by wind loads. Consequently, mechanical adaptation can only be achieved at the tissue level, and this study aims to examine how this is achieved by comparison with a softwood tree species at the tissue, fibre and cell wall levels. Methods The mechanical properties of single fibres and tissue slices of stems of mature moso bamboo (Phyllostachys pubescens) and spruce (Picea abies) latewood were investigated in microtensile tests. Cell parameters, cellulose microfibril angles and chemical composition were determined using light and electron microscopy, wide-angle X-ray scattering and confocal Raman microscopy. Key Results Pronounced differences in tensile stiffness and strength were found at the tissue and fibre levels, but not at the cell wall level. Thus, under tensile loads, the differing wall structures of bamboo (multilayered) and spruce (sandwich-like) appear to be of minor relevance. Conclusions The superior tensile properties of bamboo fibres and fibre bundles are mainly a result of amplified cell wall formation, leading to a densely packed tissue, rather than being based on specific cell wall properties. The material optimization towards extremely compact fibres with a multi-lamellar cell wall in bamboo might be a result of a plant growth strategy that compensates for the lack of secondary thickening growth at the tissue level, which is not only favourable for the biomechanics of the plant but is also increasingly utilized in terms of engineering products made from bamboo culms. PMID:25180290

  8. Effect of dynamically charged helium on tensile properties of V-5Ti, V-4Cr-4Ti, and V-3Ti-1Si

    SciTech Connect

    Chung, H.M.; Loomis, B.A.; Nowicki, L.; Smith, D.L.

    1996-04-01

    In the Dynamic Helium Charging Experiment (DHCE), helium was produced uniformly in the specimen at linear rates of {approx}0.4 to 4.2 appm He/dpa by the decay of tritium during irradiation to 18-31 dpa at 424-600{degrees}C in the lithium-filled DHCE capsules in the Fast Flux Test Facility. This report presents results of postirradiation tests of tensile properties of V-5Ti, V-4Cr-4Ti, V-3Ti-1Si. The effect of helium on tensile strength and ductility was insignificant after irradiation and testing at >420{degrees}C. Contrary to initial expectation, room temperature ductility of DHCE specimens was higher than that on non-DHCE specimens, whereas strength was lower, indicating that different types of hardening centers are produced during DHCE and non-DHCE irradiation. In strong contrast to results of tritium-trick experiments, in which dense coalescence of helium bubbles is produced on grain boundaries in the absence of displacement damage, no intergranular fracture was observed in any tensile specimens irradiated in the DHCE.

  9. Effect of UV-light on the uniaxial tensile properties and structure of uncoated and TiO2 coated Bombyx mori silk fibers

    NASA Astrophysics Data System (ADS)

    Aksakal, Baki; Koç, Kenan; Yargı, Önder; Tsobkallo, Katherina

    2016-01-01

    The effect of UV-light on the uniaxial tensile properties and the structure of uncoated and TiO2 coated silk fibers in the bave form by using sol-gel method was investigated with tensile testing and FT-IR/ATR spectroscopy methods after the silk filaments were exposed to UV-light with high intensity of 760 W/m2 for different times from 0.5 h to 1 day. It was clearly observed that TiO2 coating considerably increased the Young's modulus of the uncoated silk single filament by around 17% before the UV-irradiation. The yield point and the post yield region disappeared on the stress-strain curves of both uncoated and TiO2 coated silk filaments after UV-irradiation time higher than 1 h. Except for the Young's modulus, most of the tensile characteristics of both uncoated and TiO2 coated silk filaments decreased remarkably with increasing UV-irradiation time, e.g., after 1 h irradiation, although the Young's modulus slightly changed and ultimate tensile strength decreased by only around 18% and 23%, for the uncoated and TiO2 coated silk filaments, respectively; breaking extension decreased dramatically by 67% and 72%, respectively, for uncoated and TiO2 coated silk filaments. Only the Young's modulus of TiO2 coated silk filaments which can be considered as a more stable tensile characteristic became significantly higher than that of the uncoated silk filaments with increasing UV-irradiation time. After 1 day irradiation, even though the uncoated silk filaments could not be tested and completely lost of their fiber properties, the TiO2 coated silk filaments showed a stress-strain curve in initial elastic region with Young's modulus of ∼13 GPa which indicates considerable protective effect of TiO2 on the silk fiber structure, especially on the β-sheet microcrystals against UV-radiation. The FT-IR/ATR spectral results showed that significant photodegradation took place in not only crystalline but also amorphous regions which were deduced from the decrease in the absorbance

  10. Effect of UV-light on the uniaxial tensile properties and structure of uncoated and TiO2 coated Bombyx mori silk fibers.

    PubMed

    Aksakal, Baki; Koç, Kenan; Yargı, Önder; Tsobkallo, Katherina

    2016-01-01

    The effect of UV-light on the uniaxial tensile properties and the structure of uncoated and TiO2 coated silk fibers in the bave form by using sol-gel method was investigated with tensile testing and FT-IR/ATR spectroscopy methods after the silk filaments were exposed to UV-light with high intensity of 760W/m(2) for different times from 0.5h to 1day. It was clearly observed that TiO2 coating considerably increased the Young's modulus of the uncoated silk single filament by around 17% before the UV-irradiation. The yield point and the post yield region disappeared on the stress-strain curves of both uncoated and TiO2 coated silk filaments after UV-irradiation time higher than 1h. Except for the Young's modulus, most of the tensile characteristics of both uncoated and TiO2 coated silk filaments decreased remarkably with increasing UV-irradiation time, e.g., after 1h irradiation, although the Young's modulus slightly changed and ultimate tensile strength decreased by only around 18% and 23%, for the uncoated and TiO2 coated silk filaments, respectively; breaking extension decreased dramatically by 67% and 72%, respectively, for uncoated and TiO2 coated silk filaments. Only the Young's modulus of TiO2 coated silk filaments which can be considered as a more stable tensile characteristic became significantly higher than that of the uncoated silk filaments with increasing UV-irradiation time. After 1day irradiation, even though the uncoated silk filaments could not be tested and completely lost of their fiber properties, the TiO2 coated silk filaments showed a stress-strain curve in initial elastic region with Young's modulus of ∼13GPa which indicates considerable protective effect of TiO2 on the silk fiber structure, especially on the β-sheet microcrystals against UV-radiation. The FT-IR/ATR spectral results showed that significant photodegradation took place in not only crystalline but also amorphous regions which were deduced from the decrease in the absorbance

  11. The Relationships Between Microstructure, Tensile Properties and Fatigue Life in Ti-5Al-5V-5Mo-3Cr-0.4Fe (Ti-5553)

    NASA Astrophysics Data System (ADS)

    Foltz, John W., IV

    beta-titanium alloys are being increasingly used in airframes as a way to decrease the weight of the aircraft. As a result of this movement, Ti-5Al-5V-5Mo-3Cr-0.4Fe (Timetal 555), a high-strength beta titanium alloy, is being used on the current generation of landing gear. This alloy features good combinations of strength, ductility, toughness and fatigue life in alpha+beta processed conditions, but little is known about beta-processed conditions. Recent work by the Center for the Accelerated Maturation of Materials (CAMM) research group at The Ohio State University has improved the tensile property knowledge base for beta-processed conditions in this alloy, and this thesis augments the aforementioned development with description of how microstructure affects fatigue life. In this work, beta-processed microstructures have been produced in a Gleeble(TM) thermomechanical simulator and subsequently characterized with a combination of electron and optical microscopy techniques. Four-point bending fatigue tests have been carried out on the material to characterize fatigue life. All the microstructural conditions have been fatigue tested with the maximum test stress equal to 90% of the measured yield strength. The subsequent results from tensile tests, fatigue tests, and microstructural quantification have been analyzed using Bayesian neural networks in an attempt to predict fatigue life using microstructural and tensile inputs. Good correlation has been developed between lifetime predictions and experimental results using microstructure and tensile inputs. Trained Bayesian neural networks have also been used in a predictive fashion to explore functional dependencies between these inputs and fatigue life. In this work, one section discusses the thermal treatments that led to the observed microstructures, and the possible sequence of precipitation that led to these microstructures. The thesis then describes the implications of microstructure on fatigue life and

  12. Bio-nanocomposite films reinforced with cellulose nanocrystals: Rheology of film-forming solutions, transparency, water vapor barrier and tensile properties of films.

    PubMed

    El Miri, Nassima; Abdelouahdi, Karima; Barakat, Abdellatif; Zahouily, Mohamed; Fihri, Aziz; Solhy, Abderrahim; El Achaby, Mounir

    2015-09-20

    This study was aimed to develop bio-nanocomposite films of carboxymethyl cellulose (CMC)/starch (ST) polysaccharide matrix reinforced with cellulose nanocrystals (CNC) using the solution casting method. The CNC were extracted at the nanometric scale from sugarcane bagasse via sulfuric acid hydrolysis and used as reinforcing phase to produce CMC/ST-CNC bio-nanocomposite films at different CNC loading levels (0.5-5.0 wt%). Steady shear viscosity and dynamic viscoelastic measurements of film-forming solution (FFS) of neat CMC, CMC/ST blend and CMC/ST-CNC bio-nanocomposites were evaluated. Viscosity measurements revealed that a transition from Newtonian behavior to shear thinning occurred when CNC were added. The dynamic tests confirmed that all FFS have a viscoelastic behavior with an entanglement network structure, induced by the hydrogen bonding. In regard to the cast film quality, the rheological data showed that all FFS were suitable for casting of films at ambient temperature. The effect of CNC addition on the optical transparency, water vapor permeability (WVP) and tensile properties of bio-nanocomposite films was studied. It was found that bio-nanocomposite films remain transparent due to CNC dispersion at the nanoscale. The WVP was significantly reduced and the elastic modulus and tensile strength were increased gradually with the addition of CNC. Herein, the steps to form new eco-friendly bio-nanocomposite films were described by taking advantage of the combination of CMC, ST and CNC. The as-produced films exhibited good optical transparency, reduced WVP and enhanced tensile properties, which are the main properties required for packaging applications. PMID:26050901

  13. Acellularization-Induced Changes in Tensile Properties Are Organ Specific - An In-Vitro Mechanical and Structural Analysis of Porcine Soft Tissues

    PubMed Central

    Aust, Gabriela; Boldt, Andreas; Fritsch, Sebastian; Keil, Isabel; Koch, Holger; Möbius, Robert; Scheidt, Holger A.; Wagner, Martin F. X.; Hammer, Niels

    2016-01-01

    Introduction Though xenogeneic acellular scaffolds are frequently used for surgical reconstruction, knowledge of their mechanical properties is lacking. This study compared the mechanical, histological and ultrastructural properties of various native and acellular specimens. Materials and Methods Porcine esophagi, ureters and skin were tested mechanically in a native or acellular condition, focusing on the elastic modulus, ultimate tensile stress and maximum strain. The testing protocol for soft tissues was standardized, including the adaption of the tissue’s water content and partial plastination to minimize material slippage as well as templates for normed sample dimensions and precise cross-section measurements. The native and acellular tissues were compared at the microscopic and ultrastructural level with a focus on type I collagens. Results Increased elastic modulus and ultimate tensile stress values were quantified in acellular esophagi and ureters compared to the native condition. In contrast, these values were strongly decreased in the skin after acellularization. Acellularization-related decreases in maximum strain were found in all tissues. Type I collagens were well-preserved in these samples; however, clotting and a loss of cross-linking type I collagens was observed ultrastructurally. Elastins and fibronectins were preserved in the esophagi and ureters. A loss of the epidermal layer and decreased fibronectin content was present in the skin. Discussion Acellularization induces changes in the tensile properties of soft tissues. Some of these changes appear to be organ specific. Loss of cross-linking type I collagen may indicate increased mechanical strength due to decreasing transverse forces acting upon the scaffolds, whereas fibronectin loss may be related to decreased load-bearing capacity. Potentially, the alterations in tissue mechanics are linked to organ function and to the interplay of cells and the extracellular matrix, which is different in

  14. Effects of Intermittent Versus Continuous Heating upon the Tensile Properties of 2024-T4, 6061-T6 and 7075-T6 Alloys

    NASA Technical Reports Server (NTRS)

    Stickley, G. W.; Anerson, H. L.

    1956-01-01

    In some applications, aluminum alloys are subjected to intermittent heating at elevated temperature. It is generally considered that the effects of such intermittent heating are cumulative, and therefore are the same as if the heating had been continuous for the same total length of time. The object of these tests was to determine the effects of intermittent and continuous heating at 300 and 400 F, for total periods of 100 and 200 hr, upon the tensile properties of 2024-T4 and 6061-T6 alloy rolled-and-drawn rod and 7075-T6 alloy extrusions, at room temperature and at the temperature of heating.

  15. Thermal degradation of the tensile properties of undirectionally reinforced FP-Al2O3/EZ 33 magnesium composites

    NASA Technical Reports Server (NTRS)

    Bhatt, R.T.; Grimes, H. H.

    1983-01-01

    The effects of isothermal and cyclic exposure on the room temperature axial and transverse tensile strength and dynamic flexural modulus of 35 volume percent and 55 volume percent FP-Al203/EZ 33 magnesium composites were studied. The composite specimens were continuously heated in a sand bath maintained at 350 C for up to 150 hours or thermally cycled between 50 and 250 C or 50 and 350 C for up to 3000 cycles. Each thermal cycle lasted for a total of six minutes with a hold time of two minutes at the maximum temperature. Results indicate no significant loss in the room temperature axial tensile strength and dynamic flexural modulus of composites thermally cycled between 50 and 250 C or of composites isothermally heated at 350 C for up to 150 hours from the strength and modulus data for the untreated, as-fabricated composites. In contrast, thermal cycling between 50 and 350 C caused considerable loss in both room temperature strength and modulus. Fractographic analysis and measurement of composite transverse strength and matrix hardness of thermally cycled and isothermally heated composites indicated matrix softening and fiber/matrix debonding due to void growth at the interface and matrix cracking as the likely causes of the strength and modulus loss behavior. Previously announced in STAR as N82-21260

  16. Ultrasonic Spot Welding of Aluminum to High-Strength Low-Alloy Steel: Microstructure, Tensile and Fatigue Properties

    NASA Astrophysics Data System (ADS)

    Patel, V. K.; Bhole, S. D.; Chen, D. L.

    2014-04-01

    The structural applications of lightweight aluminum alloys inevitably involve dissimilar welding with steels and the related durability issues. This study was aimed at evaluating the microstructural change, lap shear tensile load, and fatigue resistance of dissimilar ultrasonic spot-welded joints of aluminum-to-galvanized high-strength low-alloy (HSLA) steel. Two non-uniform layers were identified in between Al and HSLA steel via SEM/EDS and XRD. One was an Al-Zn eutectic layer and the other was a thin (<2 μm) layer of intermetallic compound (IMC) of Al and Fe in the nugget zone. The lap shear tensile testing gave a maximum load of 3.7 kN and the sample failed initially in between the Al-Zn eutectic film and Al-Fe IMC, and afterward from the region containing Al on both matching fracture surfaces. The fatigue test results showed a fatigue limit of about 0.5 kN (at 1 × 107 cycles). The maximum cyclic stress at which transition of the fatigue fracture from transverse through-thickness crack growth mode to the interfacial failure mode occurs increases with increasing energy input.

  17. Thermal degradation of the tensile properties of undirectionally reinforced FP-AI203/EZ 33 magnesium composites

    NASA Technical Reports Server (NTRS)

    Bhatt, R. T.; Grimes, H. H.

    1982-01-01

    The effects of isothermal and cyclic exposure on the room temperature axial and transverse tensile strength and dynamic flexural modulus of 35 volume percent and 55 volume percent FP-Al2O3/EZ 33 magnesium composites were studied. The composite specimens were continuously heated in a sand bath maintained at 350 C for up to 150 hours or thermally cycled between 50 and 250 C or 50 and 350 C for up to 3000 cycles. Each thermal cycle lasted for a total of six minutes with a hold time of two minutes at the maximum temperature. Results indicate to significant loss in the room temperature axial tensile strength and dynamic flexural modulus of composites thermally cycled between 50 and 250 C or of composites isothermally heated at 350 C for up to 150 hours from the strength and modulus data for the untreated, as fabricated composites. In contrast, thermal cycling between 50 and 350 C caused considerable loss in both room temperature strength and modulus. Fractographic analysis and measurement of composite transverse strength and matrix hardness of thermally cycled and isothermally heated composites indicated matrix softening and fiber/matrix debonding due to void growth at the interface and matrix cracking as the likely causes of the strength and modulus loss behavior.

  18. Corrosion behavior and tensile properties of AISI 316LN stainless steel exposed to flowing sodium at 823 K

    SciTech Connect

    Pillai, S.R.; Barasi, N.S.; Khatak, H.S.; Terrance, A.L.E.; Kale, R.D.; Rajan, M.; Rajan, K.K.

    2000-02-01

    Austenitic stainless steel of the grade AISI 316 LN was exposed to flowing sodium in a loop at 823 K for 6,000 h to examine the corrosion and mass-transfer behavior. The specimens were incorporated in specially designed sample holders in the loop. These were retrieved and examined by various metallurgical techniques. Specimens were also subjected to thermal aging in the same sample holder to aid in separating the consequences of exposure to sodium from those cause by mere thermal effects. Microstructural investigations have revealed that thermal aging caused the precipitation of carbides at the grain boundaries. Exposure to sodium caused the leaching of elements such as chromium and nickel from the specimen. Loss of nickel from the austenite phase promoted the generation of ferrite phase. Microhardness investigation revealed the hardening of the sodium-exposed surface. Analysis using an electron Probe Microanalyzer revealed that the surface of the steel was both carburized and nitrided. Tensile tests indicated that there is no appreciable difference in the yield strength (YS) and ultimate tensile strength (UTS) of the thermally aged and sodium-exposed specimens when compared with the material in the as-received condition. However, the thermally aged and sodium-exposed specimens showed a decrease in the uniform elongation and total elongation at rupture, perhaps due to carburization and nitridation.

  19. Residual Stresses and Tensile Properties of Friction Stir Welded AZ31B-H24 Magnesium Alloy in Lap Configuration

    NASA Astrophysics Data System (ADS)

    Naik, Bhukya Srinivasa; Cao, Xinjin; Wanjara, Priti; Friedman, Jacob; Chen, Daolun

    2015-08-01

    AZ31B-H24 Mg alloy sheets with a thickness of 2 mm were friction stir welded in lap configuration using two tool rotational rates of 1000 and 1500 rpm and two welding speeds of 10 and 20 mm/s. The residual stresses in the longitudinal and transverse directions of the weldments were determined using X-ray diffraction. The shear tensile behavior of the lap joints was evaluated at low [233 K (-40 °C)], room [298 K (25 °C)], and elevated [453 K (180 °C)] temperatures. The failure load was highest for the lower heat input condition that was obtained at a tool rotational rate of 1000 rpm and a welding speed of 20 mm/s for all the test temperatures, due to the smaller hooking height, larger effective sheet thickness, and lower tensile residual stresses, as compared to the other two welding conditions that were conducted at a higher tool rotational rate or lower welding speed. The lap joints usually fractured on the advancing side of the top sheet near the interface between the thermo-mechanically affected zone and the stir zone. Elevated temperature testing of the weld assembled at a tool rotational rate of 1000 rpm and a welding speed of 20 mm/s led to the failure along the sheet interface in shear fracture mode due to the high integrity of the joint that exhibited large plastic deformation and higher total energy absorption.

  20. Microstructure and Tensile Properties of Mg (AM60)/Al2O3 Metal Matrix Composites with Varying Volume Fractions of Fiber Reinforcement

    NASA Astrophysics Data System (ADS)

    Zhang, Xuezhi; Fang, Li; Xiong, Bojun; Hu, Henry

    2015-12-01

    Magnesium alloy AM60 matrix-based composite reinforced with 7, 9, 11, 22, and 35 vol.% of Al2O3 fibers was squeeze cast. The microstructure and mechanical properties were investigated in comparison with the matrix alloy AM60. The results of tensile testing indicated that the addition of Al2O3 fibers to magnesium alloy AM60 led to a significant improvement in mechanical properties. As the fiber volume fraction increased, the strengths and moduli of the composites were enhanced considerably. However, the notable increase in strengths was at sacrifice in elongation. Microstructural analyses via scanning electron microscopy (SEM) revealed that the grain size decreased with increasing volume fractions of reinforcement. The restriction of grain growth by the limited inter-fiber spacing could be the primary mechanism for a reduction in the grain size of the matrix alloy. The SEM fractography evidently reveals that the debonding of fibers from the matrix alloy and the fiber cracking were two primary mechanisms for the tensile failure of the composites.

  1. Effects of Cooling Conditions on Microstructure, Tensile Properties, and Charpy Impact Toughness of Low-Carbon High-Strength Bainitic Steels

    NASA Astrophysics Data System (ADS)

    Sung, Hyo Kyung; Shin, Sang Yong; Hwang, Byoungchul; Lee, Chang Gil; Lee, Sunghak

    2013-01-01

    In this study, four low-carbon high-strength bainitic steel specimens were fabricated by varying finish cooling temperatures and cooling rates, and their tensile and Charpy impact properties were investigated. All the bainitic steel specimens consisted of acicular ferrite, granular bainite, bainitic ferrite, and martensite-austenite constituents. The specimens fabricated with higher finish cooling temperature had a lower volume fraction of martensite-austenite constituent than the specimens fabricated with lower finish cooling temperature. The fast-cooled specimens had twice the volume fraction of bainitic ferrite and consequently higher yield and tensile strengths than the slow-cooled specimens. The energy transition temperature tended to increase with increasing effective grain size or with increasing volume fraction of granular bainite. The fast-cooled specimen fabricated with high finish cooling temperature and fast cooling rate showed the lowest energy transition temperature among the four specimens because of the lowest content of coarse granular bainite. These findings indicated that Charpy impact properties as well as strength could be improved by suppressing the formation of granular bainite, despite the presence of some hard microstructural constituents such as bainitic ferrite and martensite-austenite.

  2. Microstructure and Tensile Properties of BN/SiC Coated Hi-Nicalon, and Sylramic SiC Fiber Preforms. Revised

    NASA Technical Reports Server (NTRS)

    Bhatt, Ramakrishna T.; Chen, Yuan L.; Morscher, Gregory N.

    2002-01-01

    Batch to batch and within batch variations, and the influence of fiber architecture on room temperature physical and tensile properties of BN/SiC coated Hi-Nicalon and Sylramic SiC fiber preform specimens were determined. The three fiber architectures studied were plain weave (PW), 5-harness satin (5HS), and 8-harness satin (8HS). Results indicate that the physical properties vary up to 10 percent within a batch, and up to 20 percent between batches of preforms. Load-reload (Hysteresis) and acoustic emission methods were used to analyze damage accumulation occurring during tensile loading. Early acoustic emission activity, before observable hysteretic behavior, indicates that the damage starts with the formation of nonbridged tunnel cracks. These cracks then propagate and intersect the load bearing "0 deg" fibers giving rise to hysteretic behavior. For the Hi-Nicalon preform specimens, the onset of "0 deg" bundle cracking stress and strain appeared to be independent of the fiber architecture. Also, the "0 deg" fiber bundle cracking strain remained nearly the same for the preform specimens of both fiber types. TEM analysis indicates that the CVI BN interface coating is mostly amorphous and contains carbon and oxygen impurities, and the CVI SiC coating is crystalline. No reaction exists between the CVI BN and SiC coating.

  3. Relating sensory and chemical properties of sour cream to consumer acceptance.

    PubMed

    Shepard, L; Miracle, R E; Leksrisompong, P; Drake, M A

    2013-09-01

    Sour cream is a widely popular acidified dairy product. Volatile compounds and organic acids and their specific contributions to flavor or acceptance have not been established, nor has a comprehensive study been conducted to characterize drivers of liking for sour cream. The objective of this study was to characterize chemical and sensory properties of sour cream and to determine the drivers of liking for sour cream. Descriptive sensory and instrumental analyses followed by consumer testing were conducted. Flavor and texture attributes of 32 (22 full-fat, 6 reduced-fat, and 4 fat-free) commercial sour creams were evaluated by a trained descriptive sensory panel. Percent solids, percent fat, pH, titratable acidity, and colorimetric measurements were conducted to characterize physical properties of sour creams. Organic acids were evaluated by HPLC and volatile aroma active compounds were evaluated by gas chromatography-mass spectrometry with gas chromatography-olfactometry. Consumer acceptance testing (n=201) was conducted on selected sour creams, followed by external preference mapping. Full-fat sour creams were characterized by the lack of surface gloss and chalky textural attributes, whereas reduced-fat and fat-free samples displayed high intensities of these attributes. Full-fat sour creams were higher in cooked/milky and milk fat flavors than the reduced-fat and fat-free samples. Reduced-fat and fat-free sour creams were characterized by cardboard, acetaldehyde/green, and potato flavors, bitter taste, and astringency. Lactic acid was the prominent organic acid in all sour creams, followed by acetic and citric acids. High aroma-impact volatile compounds in sour creams were 2,3-butanedione, acetic acid, butyric acid, octanal, 2-methyl-3-furanthiol, 1-octene-3-one, and acetaldehyde. Positive drivers of liking for sour cream were milk fat, cooked/milky and sweet aromatic flavors, opacity, color intensity, and adhesiveness. This comprehensive study established

  4. Effects of long-term thermal aging on the tensile and creep properties of commercially heat-treated alloy 718

    SciTech Connect

    Booker, M.K.

    1984-01-01

    Alloy 718 is a structure material widely used in elevated-temperature applications. In particular, it was extensively used in the design of the upper internal system and control rod drive line of the proposed Clinch River Breeder Reactor. Its popularity is due to several excellent behavioral features, including high creep and creep-rupture strength, good oxidation resistance, and exceptional high-cycle fatigue strength. However, alloy 718 is extremely complex, and its microstructure can be significantly modified by thermal treatment. The stability of the alloy in long-term elevated-temperature service is therefore a substantial concern in any such application. This report presents tensile and creep data obtained on three heats of alloy 718 after thermal aging for up to 27,000 h from 593 to 76{degree}C. Implications of these results in terms of long-term stability of the alloy are discussed. 5 refs., 13 figs., 6 tabs.

  5. Largely improved tensile properties of chitosan film via unique synergistic reinforcing effect of carbon nanotube and clay.

    PubMed

    Tang, Changyu; Xiang, Lixue; Su, Juanxia; Wang, Ke; Yang, Changyue; Zhang, Qin; Fu, Qiang

    2008-04-01

    In this work, a great synergistic effect of 2D clay platelets and 1D carbon nanotubes (CNTs) on reinforcing chitosan matrix has been observed for the first time. With incorporation of 3 wt % clay and 0.4 wt % CNTs, the tensile strength and Young's modulus of the nanocomposites are significantly improved by about 171 and 124%, respectively, compared with neat chitosan. This could be understood as due to the formation of much jammed fillers network with 1D CNTs and 2D clay platelets combined together, as indicated by rheological measurement. Our work demonstrates a good example for the preparation of high performance polymer nanocomposites by using nanofillers of different dimension together. PMID:18335921

  6. Bisimide amine cured epoxy /IME/ resins and composites. II - Ten-degree off-axis tensile and shear properties of Celion 6000/IME composites

    NASA Technical Reports Server (NTRS)

    Scola, D. A.

    1982-01-01

    Bisimide amines (BIAs), which are presently used as curing agents in a state-of-the-art epoxy resin, are oligomeric and polymeric mixtures. A series of composites consisting of the novel BIA-cured epoxy resin reinforced with Celion 6000 graphite fibers were fabricated and evaluated, and the ten-degree, off-axis uniaxial tensile and shear properties of these composites were determined. The use of the intralaminar shear strain-to-failure was used in the calculation of resin shear strain-to-failure. Study results indicate that several of these novel composite systems exhibit shear strain properties that are superior to those of the control composite system of the present experiments, which employed a sulfone curing agent.

  7. Tensile Creep and Fatigue of Sylramic-iBN Melt-Infiltrated SiC Matrix Composites: Retained Properties, Damage Development, and Failure Mechanisms

    NASA Technical Reports Server (NTRS)

    Morscher, Greg; Gowayed, yasser; Miller, Robert; Ojard, Greg; Ahmad, Jalees; Santhosh, Unni; John, Reji

    2008-01-01

    An understanding of the elevated temperature tensile creep, fatigue, rupture, and retained properties of ceramic matrix composites (CMC) envisioned for use in gas turbine engine applications are essential for component design and life-prediction. In order to quantify the effect of stress, time, temperature, and oxidation for a state-of-the-art composite system, a wide variety of tensile creep, dwell fatigue, and cyclic fatigue experiments were performed in air at 1204 C for the SiC/SiC CMC system consisting of Sylramic-iBN SiC fibers, BN fiber interphase coating, and slurry-cast melt-infiltrated (MI) SiC-based matrix. Tests were either taken to failure or interrupted. Interrupted tests were then mechanically tested at room temperature to determine the residual properties. The retained properties of most of the composites subjected to tensile creep or fatigue were usually within 20% of the as-produced strength and 10% of the as-produced elastic modulus. It was observed that during creep, residual stresses in the composite are altered to some extent which results in an increased compressive stress in the matrix upon cooling and a subsequent increased stress required to form matrix cracks. Microscopy of polished sections and the fracture surfaces of specimens which failed during stressed-oxidation or after the room-temperature retained property test was performed on some of the specimens in order to quantify the nature and extent of damage accumulation that occurred during the test. It was discovered that the distribution of stress-dependent matrix cracking at 1204 C was similar to the as-produced composites at room temperature; however, matrix crack growth occurred over time and typically did not appear to propagate through thickness except at final failure crack. Failure of the composites was due to either oxidation-induced unbridged crack growth, which dominated the higher stress regime (> 179 MPa) or controlled by degradation of the fibers, probably caused by

  8. Effects of excipients on the tensile strength, surface properties and free volume of Klucel® free films of pharmaceutical importance

    NASA Astrophysics Data System (ADS)

    Gottnek, Mihály; Süvegh, Károly; Pintye-Hódi, Klára; Regdon, Géza

    2013-08-01

    The physicochemical properties of polymers planned to be applied as mucoadhesive films were studied. Two types of Klucel® hydroxypropylcellulose (LF and MF) were used as film-forming polymers. Hydroxypropylcellulose was incorporated in 2 w/w% with glycerol and xylitol as excipients and lidocaine base as an active ingredient at 5, 10 or 15 w/w% of the mass of the film-forming polymer. The free volume changes of the films were investigated by positron annihilation lifetime spectroscopy, the mechanical properties of the samples were measured with a tensile strength tester and contact angles were determined to assess the surface properties of the films. It was found that the Klucel® MF films had better physicochemical properties than those of the LF films. Klucel® MF as a film-forming polymer with lidocaine base and both excipients at 5 w/w% exhibited physicochemical properties and good workability. The excipients proved to exert strong effects on the physicochemical properties of the tested systems and it is very important to study them intensively in preformulation studies in the pharmaceutical technology in order to utilise their benefits and to avoid any disadvantageous effects.

  9. 24 CFR 1710.558 - Previously accepted state filings-notice of revocation rights on property report cover page.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...-notice of revocation rights on property report cover page. 1710.558 Section 1710.558 Housing and Urban....558 Previously accepted state filings—notice of revocation rights on property report cover page. (a)(1... after 15 percent of the purchase price, exclusive of interest, has been paid, the seller shall refund...

  10. 24 CFR 1710.558 - Previously accepted state filings-notice of revocation rights on property report cover page.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...-notice of revocation rights on property report cover page. 1710.558 Section 1710.558 Housing and Urban....558 Previously accepted state filings—notice of revocation rights on property report cover page. (a)(1... after 15 percent of the purchase price, exclusive of interest, has been paid, the seller shall refund...

  11. 24 CFR 1710.558 - Previously accepted state filings-notice of revocation rights on property report cover page.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...-notice of revocation rights on property report cover page. 1710.558 Section 1710.558 Housing and Urban....558 Previously accepted state filings—notice of revocation rights on property report cover page. (a)(1... after 15 percent of the purchase price, exclusive of interest, has been paid, the seller shall refund...

  12. 24 CFR 1710.558 - Previously accepted state filings-notice of revocation rights on property report cover page.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...-notice of revocation rights on property report cover page. 1710.558 Section 1710.558 Housing and Urban....558 Previously accepted state filings—notice of revocation rights on property report cover page. (a)(1... after 15 percent of the purchase price, exclusive of interest, has been paid, the seller shall refund...

  13. 12 CFR 1010.558 - Previously accepted state filings-notice of revocation rights on property report cover page.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... revocation rights on property report cover page. 1010.558 Section 1010.558 Banks and Banking BUREAU OF... State Law § 1010.558 Previously accepted state filings—notice of revocation rights on property report... purchaser's default or breach of contract after 15 percent of the purchase price, exclusive of interest,...

  14. Data Qualification and Data Summary Report: Intact Rock Properties Data on Tensile Strength, Schmidt Hammer Rebound Hardness, and Rock Triaxial Creep

    SciTech Connect

    E.M. Cikanek; R.J. Blakely; T.A. Grant; L.E. Safley

    2003-07-29

    This report presents a systematic review of the available data in the TDMS that are relevant to the following intact rock properties: rock tensile strength, Schmidt hammer rebound hardness, and rock triaxial creep. Relevant data are compiled from qualified and unqualified sources into the summary DTNs and these DTNs are evaluated for qualification using the method of corroborating data as defined in AP-SIII.2Q, ''Qualification of Unqualified Data''. This report also presents a summary of the compiled information in the form of descriptive statistics and recommended values that will be contained in a Reference Information Base (RIB) item prepared in accordance with AP-SIII.4Q, ''Development, Review, Online Placement, and Maintenance of Individual Reference Information Base Data Items''. The primary purpose of this report is to produce qualified sets of data that include all relevant intact rock tensile strength, Schmidt hammer rebound hardness, and rock triaxial creep testing done over the course of the Yucca Mountain Project (YMP). A second purpose is to provide a qualified summary (i.e., a RIB data item) of the test results using descriptive statistics. The immediate purpose of the report is to support the data needs of repository design; however, the products are designed to be appropriate for general use by the YMP. The appropriateness and limitations, if any, of the data, with respect to the intended use, are addressed in this report.

  15. Effect of FFTF irradiation on tensile properties of P- and Ti-modified model austenitic alloys with small amounts of boron

    NASA Astrophysics Data System (ADS)

    Kurishita, H.; Muroga, T.; Watanabe, H.; Yoshida, N.; Kayano, H.; Hamilton, M. L.

    1994-09-01

    The interactive effects of P and Ti additions, {helium}/{dpa} ratio, irradiation and test temperature on postirradiation tensile properties of a model Fe-16Cr-17Ni alloy were investigated. Miniature tensile specimens containing 64 and 522 appm 10B (0.75 and 3.8 {He}/{dpa} ratio), with and without 0.1 wt% P and 0.25 wt% Ti additions, were irradiated to 33 dpa at 703, 793 and 874 K in the Fast Flux Test Facility (FFTF). They were deformed at 300, 473 and 673 K. For all the alloy conditions the irradiation at 703 K increases the yield stress and decreases the uniform elongation significantly. An effect of 10B addition occurs, which is not related to helium generation, but it is small compared to the effects of P and Ti additions. Additions of P and Ti, especially their simultaneous addition, cause a significant strengthening but no appreciable change in uniform elongation. The cause of the strengthening and the observed changes in uniform elongation are discussed.

  16. Tensile properties of HA 230 and HA 188 after 400 and 2500 hour exposures to LiF-22CaF2 and vacuum at 1093 K

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. Daniel

    1990-01-01

    The solid-to-liquid phase transformation of the nominal LiF-20CaF2 eutectic at 1043 K is considered to be an ideal candidate thermal energy storage mechanism for a space based low temperature Brayton cycle solar dynamic system. Although Co, Fe, and Ni superalloys are thought to be suitable containment materials for LiF based salts, long term containment is of concern because molten fluorides are usually corrosive and Cr can be lost into space through evaporation. Two examples of commercially available superalloys in sheet form, the Ni-base material HA 230 and the Co-base material Ha 88, have been exposed to molten LiF-22CaF2, its vapor, and vacuum, at 1093 K, for 400 and 2500 hr. Triplicate tensile testing of specimens subjected to all three environments have been undertaken between 77 to 1200 K. Comparison of the weight gain data, microstructure, and tensile properties indicate that little, if any, difference in behavior can be ascribed to the exposure environment.

  17. Tensile properties of cast titanium alloys: Titanium-6Al-4V ELI and Titanium-5Al-2.5Sn ELI

    NASA Technical Reports Server (NTRS)

    Billinghurst, E. E., Jr.

    1992-01-01

    This work was performed to determine the tensile properties of cast, hot isostatic pressed (HIP'ed), and annealed titanium alloys, Ti-6Al-4V ELI and Ti-5Al-2.5Sn ELI, that are candidate materials for the space transportation main engine (STME) liquid hydrogen turbopump impeller. Samples of the cast alloys were HIP'ed, annealed, and machined into tensile specimens. The specimens were tested in air at ambient temperature (70 F) and also at -423 F in liquid hydrogen. The Ti-6Al-4V alloy had an average ultimate strength of 129.1 ksi at 70 F and 212.2 ksi at -423 F. The Ti-5Al-2.5Sn alloy had an average ultimate strength of 108.4 ksi at 70 degrees F and 185.0 ksi at -423 F. The ductility, as measured by reduction of area, for the Ti-6Al-4V averaged 15.2 percent at 70 F and 8.7 percent at -423 F, whereas for the Ti-5Al-2.5Sn alloy average reduction of area was 24.6 percent at 70 F and 11.7 percent at -423 F.

  18. Elevated temperature tensile properties of irradiated 20/25/Nb stainless steel fuel pin cladding at low and high strain rates

    NASA Astrophysics Data System (ADS)

    Gravenor, J. G.; Douglas, J.

    1988-09-01

    Tensile specimens were prepared from 20/25/Nb stainless steel fuel pin cladding irradiated in a Commercial Advanced Gas-cooled Reactor (CAGR) at temperatures in the range 622-866 K and integrated fast neutron doses up to 16 × 10 24n/ m2. The tests were performed in air at temperatures in the range 298-873 K at strain rates from 2 × 10 -5s-1 to 7.2 s -1. The tensile properties varied with irradiation temperature, test temperature and strain rate. At lower irradiation temperature, strengthening produced by fast neutron damage was accompanied by reduced elongation. Strengthening was also observed at higher irradiation temperatures, possibly due to precipitation phenomena. The maximum irradiation embrittlement was observed in tests at 873 K at low strain rates between 2 × 10 -4s-1 and 2 × 10 -5s-1. The failure mode of embrittled specimens irradiated at higher temperatures was characterized by prematurely ruptured ductile fibres, rather than by intergranular cracking.

  19. A metallographic study of porosity and fracture behavior in relation to the tensile properties in 319.2 end chill castings

    SciTech Connect

    Samuel, A.M.; Samuel, F.H.

    1995-09-01

    A metallographic study of the porosity and fracture behavior in unidirectionally solidified end chill castings of 319.2 aluminum alloy (Al-6.2 pct Si-3.8 pct Cu-0.5 pct Fe-0.14 pct Mn-0.06 pct Mg-0.073 pct Ti) was carried out using optical microscopy and scanning electron microscopy (SEM) to determine their relationship with the tensile properties. The parameters varied in the production of these castings were the hydrogen ({approximately}0.1 and {approximately}0.37 mL/100 g Al), modifier (0 and 300 ppm Sr), and grain refiner (0 and 0.03 wt pct Ti) concentrations, as well as the solidification time, which increased with decreasing distance from the end chill bottom of the casting, giving dendrite arm spacings (DASs) ranging from {approximately}15 to {approximately}95 {micro}m. Image analysis and energy dispersive X-ray (EDX) analysis were employed for quantification of porosity/microstructural constituents and fracture surface analysis (phase identification), respectively. The results showed that the local solidification time (viz. DAS) significantly influences the ductility at low hydrogen levels; at higher levels, however, hydrogen has a more pronounced effect (porosity related) on the drop in ductility. Porosity is mainly observed in the form of elongated pores along the grain boundaries, with Sr increasing the porosity volume percent and grain refining increasing the probability for pore branching. The beneficial effect of Sr modification, however, improves the alloy ductility. Fracture of the Si, {beta}-Al{sub 5}FeSi, {alpha}-Al{sub 15}(Fe,Mn){sub 3}Si{sub 2}, and Al{sub 2}Cu phases takes place within the phase particles rather than at the particle/Al matrix interface. Sensitivity of tensile properties to DAS allows for the use of the latter as an indicator of the expected properties of the alloy.

  20. Effects of Fiber Coatings on Tensile Properties of Hi-Nicalon SiC/RBSN Tow Composites

    NASA Technical Reports Server (NTRS)

    Bhatt, Ramakrishna T.; Hull, David R.

    1997-01-01

    Uncoated Hi-Nicalon silicon carbide (SiC) fiber tows and those coated with a single surface layer of pyrolytic boron nitride (PBN), double layers of PBN/Si-rich PBN, and boron nitride (BN)/SiC coatings deposited by chemical vapor deposition (CVD) method were infiltrated with silicon slurry and then exposed to N2, for 4 hr at 1200 and 1400 C. Room temperature ultimate tensile fracture loads and microstructural characterization of uncoated and CVD coated Hi-Nicalon SiC fiber reinforced reaction-bonded silicon nitride (RBSN) tow composites were measured to select suitable interface coating(s) stable under RBSN processing conditions. Results indicate that room temperature ultimate fracture loads of the uncoated Hi-Nicalon SiC/RBSN tow composites nitrided at both temperatures were significantly lower than those of the uncoated Hi-Nicalon tows without slurry infiltration. In contrast, all CVD coated Hi-Nicalon SiC/RBSN tow composites retained a greater fraction of the dry tow fracture load after nitridation at 1200 C, but degraded significantly after nitridation at 1400 C. Reaction between metal impurities (Fe and Ni) present in the attrition milled silicon powder and uncoated regions of SiC fibers appears to be the probable cause for fiber degradation.

  1. Evaluation of the effect of different stretching patterns on force decay and tensile properties of elastomeric ligatures

    PubMed Central

    Aminian, Amin; Nakhaei, Samaneh; Agahi, Raha Habib; Rezaeizade, Masoud; Aliabadi, Hamed Mirzazadeh; Heidarpour, Majid

    2015-01-01

    Background: There have been numerous researches on elastomeric ligatures, but clinical conditions in different stages of treatment are not exactly similar to laboratory conditions. The aim of this in vitro study was to simulate clinical conditions and evaluate the effect of three stretching patterns on the amount of force, tensile strength (TS) and extension to TS of the elastomers during 8 weeks. Materials and Methods: Forces, TS and extension to TS of two different brands of elastomers were measured at initial, 24 h and 2, 4, and 8-week intervals using a testing machine. During the study period, the elastomers were stored in three different types of jig (uniform stretching, 1 and 3 mm point stretching) designed by the computer-aided design and computer-aided manufacturing technique in order to simulate the different stages of orthodontic treatment. Results: The elastomeric ligatures under study exhibited a similar force decay pattern. The maximum force decay occurred during the first 24 h (49.9% ± 15%) and the amount of force decay was 75.7% ± 8% after 8 weeks. In general, the TS decreased during the study period, and the amount of extension to TS increased. Conclusion: Although the elastic behavior of all ligatures under study was similar, the amount of residual force, TS and extension to TS increased in elastomers under point stretching pattern. PMID:26759597

  2. Statistical properties of microcracking in polyurethane foams under tensile and creep tests: influence of temperature and density.

    NASA Astrophysics Data System (ADS)

    Deschanel, Stephanie; Vigier, Gerard; Godin, Nathalie; Vanel, Loic; Ciliberto, Sergio

    2007-03-01

    For some heterogeneous materials fracture can be described as a clustering of microcracks: global rupture being not controlled by a single event. We focus on polyurethane foams whose heterogeneities (pores) constitute the termination points where microcracks can stop. We record both the spatial and time distributions of acoustic emission emitted by a sample during mechanical tests: each microcrack nucleation corresponds to a burst of energy that can be localized on the widest face of the specimen. The probability distributions of the energy released is power-law distributed, independently of the material density, the loading mode or the mechanical behavior. On the other hand, the agreement of a power law for the time intervals between two damaging events seems to require a quasi constant stress during damaging. Moreover, we notice a behavior difference of the cumulative number of events and the cumulative energy of the localized events with temperature in the case of tensile tests and not any more for creep tests. The occurrence of a unique behavior and a power law in a restricted time interval for the cumulative number of events and the cumulative energy in creep allow us to apprehend interesting later studies of materials' lifetime prediction.

  3. Effect of strain rate on the tensile properties of unirradiated and irradiated V-4Cr-4Ti

    NASA Astrophysics Data System (ADS)

    Rowcliffe, A. F.; Zinkle, S. J.; Hoelzer, D. T.

    2000-12-01

    Tensile tests were carried out on an annealed, unirradiated V-4Cr-4Ti alloy from RT to 850°C at strain rates ranging from 10-1 to 10-5 s-1. Below 300°C, where interstitial solutes are relatively immobile, deformation is homogeneous, and the strain rate sensitivity (SRS) of the yield and flow stress is positive. Between 300°C and 700°C, the formation of solute atmospheres at locked dislocations results in dynamic strain-aging (DSA), deformation becomes heterogeneous, and the SRS of the flow stress is negative; in this regime the lower yield stress is independent of strain rate. Above 700°C, substitutional solutes are also mobile, DSA declines, and the material enters a power law creep regime in which the SRS becomes positive again. Following neutron irradiation to 0.5 dpa at temperatures ⩽400°C, severe flow localization occurs due to the high number density of <1 1 0> and <1 1 1> loops. However, above 400°C, strain hardening capacity returns but without the Lüders extension. At 500°C, after several percent plastic deformation, DSA occurs as interstitial solutes are released from the defect structure.

  4. Effect of Orientation on the Tensile and Creep Properties of Coarse-Grained INCONEL Alloy MA754

    SciTech Connect

    Terry C. Totemeier; Thomas M. Lillo

    2005-03-01

    Elevated temperature tensile and creep-rupture tests were performed on INCONEL MA754 in longitudinal and transverse orientations at temperatures from 700 to 1000°C. The transverse orientation was weaker and less ductile than the longitudinal orientation due to a higher grain boundary density perpendicular to the applied stress axis. This effect was especially pronounced in creep tests at 900 and 1000°C. Threshold creep behavior was observed for the longitudinal orientation, with stress exponents ranging from 29 to 40. Stress exponents in the long transverse orientation ranged from 24 at 800°C to 5 at 1000°C, indicating a temperature-varying deformation mechanism. Creep ductility in the transverse orientation was extremely low, less than 1 pct for higher temperature, lower stress conditions. Failure in all transverse specimens was controlled by grain boundary separation. Even in the relatively weak transverse direction, the strength of MA754 compares favorably with other alloys being considered for advanced power plant applications.

  5. Effect of open hole on tensile failure properties of 2D triaxial braided textile composites and tape equivalents

    NASA Technical Reports Server (NTRS)

    Norman, Timothy L.; Anglin, Colin; Gaskin, David; Patrick, Mike

    1995-01-01

    The unnotched and notched (open hole) tensile strength and failure mechanisms of two-dimensional (2D) triaxial braided composites were examined. The effect of notch size and notch position were investigated. Damage initiation and propagation in notched and unnotched coupons were also examined. Theory developed to predict the normal stress distribution near an open hole and failure for tape laminated composites was evaluated for its applicability to triaxial braided textile composite materials. Four fiber architectures were considered with different combinations of braid angle, longitudinal and braider yam size, and percentage of longitudinal yarns. Tape laminates equivalent to textile composites were also constructed for comparison. Unnotched tape equivalents were stronger than braided textiles but exhibited greater notch sensitivity. Notched textiles and tape equivalents have roughly the same strength at large notch sizes. Two common damage mechanisms were found: braider yams cracking and near notch longitudinal yarn splitting. Cracking was found to initiate in braider yarns in unnotched and notched coupons, and propagate in the direction of the braider yarns until failure. Longitudinal yarn splitting occurred in three of four architectures that were longitudinally fiber dominated. Damage initiation stress decreased with increasing braid angle. No significant differences in prediction of near notch stress between measured and predicted stress were weak for textiles with large braid angle. Notch strength could not be predicted using existing anisotropic theory for braided textiles due to their insensitivity to notch.

  6. Effect of Fiber Strength on the Room Temperature Tensile Properties of Sic/Ti-24Al-11Nb

    NASA Technical Reports Server (NTRS)

    Draper, S. L.; Brindley, P. K.; Nathal, M. V.

    1991-01-01

    SCA-6 SiC fibers of known strength were incorporated into SiC/Ti-24Al-11Nb (at. percent) composites and the effect of fiber strength variability on room temperature composite strength was investigated. Fiber was etched out of a composite fabricated by the powder cloth technique and the effect of the fabrication process on fiber strength was assessed. The strength of the composite was directly correlated with the strength of the as-received fiber. The strength of composite plates containing mixed fiber strengths was dominated by the lower strength fiber. Fabrication by the powder cloth technique resulted in only a slight degradation of fiber strength. The strength of the composite was found to be overestimated by the rule of mixtures strength calculation. Examination of failed tensile specimens revealed periodic fiber cracks and the failure mode was concluded to be cumulative. With the variation in fiber strength eliminated, the composite UTS was found to have a positive correlation with volume fraction of fiber.

  7. Tensile properties of austenitic stainless steels and their weld joints after irradiation by the ORR-spectrally-tailoring experiment

    NASA Astrophysics Data System (ADS)

    Jitsukawa, S.; Maziasz, P. J.; Ishiyama, T.; Gibson, L. T.; Hishinuma, A.

    1992-09-01

    Tensile specimens of the Japanese heat of PCA (JPCA) and type 316 stainless steels were irradiated in spectrally tailored capsules in the Oak Ridge Research Reactor (ORR) to a peak dose of 7.4 dpa and a peak helium level of 105 appm in the temperature range between 328 and 673 K. Specimens of type 316 steel with weld joints produced by tungsten inert gas (TIG) and electron beam (EB) welding techniques were also included. Irradiation caused both increases in flow stress and decreases in elongation. Weld joint specimens exhibited both lower strength and elongation after irradiation. The reduction of area (RA) for the TIG weld joint specimens decreased by a factor of 5 compared to unirradiated base metal specimens, however, they still fractured in a ductile mode. The EB weld joints maintained RA levels similar to that of the unirradiated base metal specimens. Post-radiation ductilities of weld joints and base metal specimens of these steels should be adequate for their application to next generation fusion experimental devices, such as the International Tokamak Experimental Reactor (ITER).

  8. Rate effect on mechanical properties of hydraulic concrete flexural-tensile specimens under low loading rates using acoustic emission technique.

    PubMed

    Su, Huaizhi; Hu, Jiang; Tong, Jianjie; Wen, Zhiping

    2012-09-01

    Acoustic emission (AE) waveform is generated by dislocation, microcracking and other irreversible changes in a concrete material. Based on the AE technique (AET), this paper focuses on strain rate effect on physical mechanisms of hydraulic concrete specimens during the entire fracture process of three point bending (TPB) flexural tests at quasi-static levels. More emphasis is placed on the influence of strain rate on AE hit rate and AE source location around peak stress. Under low strain rates, namely 0.77×10(-7)s(-1), 1×10(-7)s(-1) to 1×10(-6)s(-1) respectively, the results show that the tensile strength increases as the strain rate increases while the peak AE hit rate decreases. Meanwhile, the specimen under a relatively higher strain rate shows a relatively wider intrinsic process zone in a more diffuser manner, lots of distributed microcracks relatively decrease stress intensity, thus delay both microcracking localization and macrocrack propagation. These phenomena can be attributed to Stéfan effect. In addition, further tests, namely the combination of AE monitoring and strain measuring systems was designed to understand the correlation between AE event activity and microfracture (i.e., microcracking and microcracking localization). The relative variation trend of cumulative AE events accords well with that of the load-deformation curve. PMID:22534061

  9. Tensile properties, residual stress distribution and grain arrangement as a function of sheet thickness of Mg-Al-Mn alloy subjected to two-sided and simultaneous LSP impacts

    NASA Astrophysics Data System (ADS)

    Luo, K. Y.; Liu, B.; Wu, L. J.; Yan, Z.; Lu, J. Z.

    2016-04-01

    Two-sided and simultaneous laser shock peening impacts is considered as a novel surface treatment technology for the turbine blade and thin-walled component. In this paper, tensile properties of Mg-Al-Mn alloy specimens with different sheet thickness under two kinds of laser shock peening strategies were investigated, and an overlapping three-dimension axisymmetric numerical model was developed to analyze the effects of sheet thickness on residual stress distributions. Meanwhile, special attentions were paid to the in-depth microstructural evolution as a function of sheet thickness. Results showed that sheet thickness had an important influence on the tensile properties of Mg-Al-Mn alloy, and the generated residual stress distribution and grain arrangement were two important factors. The corresponding influence mechanism of sheet thickness on the tensile properties of Mg-Al-Mn alloy was also presented, and the optimal thickness of Mg-Al-Mn alloy sheet may be 4 mm or more.

  10. Tensile Properties of 7075-T6 and 2024-T3 Aluminum-alloy Sheet Heated at Uniform Temperature Rates Under Constant Load

    NASA Technical Reports Server (NTRS)

    Heimerl, George J; Inge, John E

    1955-01-01

    Results are presented of tests to determine the effect of heating at uniform temperature rates from 0.2 degrees to 100 degrees F. per second on the tensile properties of 7075-T6 d(75s-T6) and 2024-T3 (24s-T3) aluminum-alloy sheet under constant-load conditions. Yield and rupture stresses, obtained under rapid-heating conditions, are compared with results of elevated-temperature stress-strain tests for 1/2-hour exposure. Master yield-and-rupture-stress curves based on linear temperature-rate parameter are presented. Yield and rupture stresses and temperatures may be predicted by means of master curves and the parameter.

  11. Effect of Friction Stir Processing on Microstructure and Tensile Properties of an Investment Cast Al-7Si-0.6Mg Alloy

    SciTech Connect

    Jana, Saumyadeep; Mishra, Rajiv S.; Baumann, John B.; Grant, Glenn J.

    2010-10-01

    Friction stir processing (FSP) is emerging as a promising tool for microstructural modification. The present study assesses the effects of FSP on the microstructure and mechanical properties of an investment cast Al-7Si-Mg alloy. FSP eliminates porosity and significantly refines eutectic Si particles. The extent of particle refinement varied with changes in processing conditions. High tool rotation rate and low to intermediate tool traverse speed generated a higher volume fraction of finer particles. Tensile ductility changed significantly as a result of FSP, whereas UTS improved only marginally. Yield strength was similar in both cast and FSPed samples under various heat treated conditions, with the highest value obtained after a T6 heat treatment. Further, FSP caused significant grain refinement in the stir zone, subsequently transforming into very coarse grains as abnormal grain growth (AGG) occurred during solution treatment at high temperature.

  12. Quantitative evaluation of collagen crosslinks and corresponding tensile mechanical properties in mouse cervical tissue during normal pregnancy.

    PubMed

    Yoshida, Kyoko; Jiang, Hongfeng; Kim, MiJung; Vink, Joy; Cremers, Serge; Paik, David; Wapner, Ronald; Mahendroo, Mala; Myers, Kristin

    2014-01-01

    The changes in the mechanical integrity of the cervix during pregnancy have implications for a successful delivery. Cervical collagens are known to remodel extensively in mice with progressing gestation leading to a soft cervix at term. During this process, mature crosslinked collagens are hypothesized to be replaced with immature less crosslinked collagens to facilitate cervical softening and ripening. To determine the mechanical role of collagen crosslinks during normal mouse cervical remodeling, tensile load-to-break tests were conducted for the following time points: nonpregnant (NP), gestation day (d) 6, 12, 15, 18 and 24 hr postpartum (PP) of the 19-day gestation period. Immature crosslinks (HLNL and DHLNL) and mature crosslinks (DPD and PYD) were measured using ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS). There were no significant changes in the total immature crosslink density (HLNL+DHLNL mol per collagen mol) throughout normal mouse gestation (range: 0.31-0.49). Total mature crosslink density (PYD+DPD mol per collagen mol) decreased significantly in early softening from d6 to d15 (d6: 0.17, d12: 0.097, d15: 0.026) and did not decrease with further gestation. The maturity ratio (total mature to total immature crosslinks) significantly decreased in early softening from d6 to d15 (d6: 0.2, d15: 0.074). All of the measured crosslinks correlated significantly with a measure of tissue stiffness and strength, with the exception of the immature crosslink HLNL. This data provides quantitative evidence to support the hypothesis that as mature crosslinked collagens decline, they are replaced by immature collagens to facilitate increased tissue compliance in the early softening period from d6 to d15. PMID:25397407

  13. 41 CFR 102-75.1140 - What is the policy governing the acceptance or rejection of a conditional gift of real property...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... governing the acceptance or rejection of a conditional gift of real property for a particular defense... governing the acceptance or rejection of a conditional gift of real property for a particular defense... action taken with respect to acceptance or rejection of the conditional gift and of its final disposition....

  14. 41 CFR 102-75.1140 - What is the policy governing the acceptance or rejection of a conditional gift of real property...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... governing the acceptance or rejection of a conditional gift of real property for a particular defense... governing the acceptance or rejection of a conditional gift of real property for a particular defense... action taken with respect to acceptance or rejection of the conditional gift and of its final disposition....

  15. 41 CFR 102-75.1140 - What is the policy governing the acceptance or rejection of a conditional gift of real property...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... governing the acceptance or rejection of a conditional gift of real property for a particular defense... governing the acceptance or rejection of a conditional gift of real property for a particular defense... action taken with respect to acceptance or rejection of the conditional gift and of its final disposition....

  16. 41 CFR 102-75.1140 - What is the policy governing the acceptance or rejection of a conditional gift of real property...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... governing the acceptance or rejection of a conditional gift of real property for a particular defense... governing the acceptance or rejection of a conditional gift of real property for a particular defense... action taken with respect to acceptance or rejection of the conditional gift and of its final disposition....

  17. 41 CFR 102-75.1140 - What is the policy governing the acceptance or rejection of a conditional gift of real property...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... governing the acceptance or rejection of a conditional gift of real property for a particular defense... governing the acceptance or rejection of a conditional gift of real property for a particular defense... action taken with respect to acceptance or rejection of the conditional gift and of its final disposition....

  18. The effects on tensile, shear, and adhesive mechanical properties when recycled epoxy/fiberglass is used as an alternative for glass microballoons in fiberglass foam core sandwiches

    NASA Astrophysics Data System (ADS)

    Wilson, Dru Matthew

    The problem of this study was to determine whether fiberglass foam core sandwiches made with recycled epoxy/fiberglass have equal or better flatwise tension, shear, and peel (adhesion) mechanical properties when compared with composite sandwiches made with industry standard glass microballoons. Recycling epoxy/fiberglass could save money by: (1) reusing cured composite materials, (2) consuming less virgin composite materials, (3) spending less on transportation and disposing of unusable composites, and (4) possibly enabling companies to sell their recycled composite powder to other manufacturers. This study used three mechanical property tests, which included: flatwise tensile test, shear test, and peel (adhesion) test. Each test used 300 samples for a combined total of 900 sandwich test samples for this study. A factorial design with three independent variables was used. The first variable, filler type, had three levels: no filler, microballoon filler, and recycled epoxy/fiberglass filler. The second variable, foam density, had four levels: 3 lb/ft³, 4 lb/ft³, 5 lb/ft³, and 6 lb/ft³. The third variable, filler percentage ratio, had eight levels: 0%, 10%, 20%, 30%, 40%, 50%, 60%, and 70%. The results of this study revealed two primary conclusions. The first conclusion was that sandwich test panels produced with recycled epoxy/fiberglass powder were equal or significantly better in tensile, shear, and peel (adhesion) strength than sandwiches produced with hollow glass microballoons. The second conclusion was that sandwich test panels produced with recycled epoxy/fiberglass powder were equal or significantly lighter in weight than sandwiches produced with hollow glass microballoons.

  19. Effect of fiber distribution and realignment on the nonlinear and inhomogeneous mechanical properties of human supraspinatus tendon under longitudinal tensile loading

    PubMed Central

    Lake, Spencer P.; Miller, Kristin S.; Elliott, Dawn M.; Soslowsky, Louis J.

    2010-01-01

    Tendon exhibits nonlinear stress-strain behavior that may be due, in part, to movement of collagen fibers through the extracellular matrix. While a few techniques have been developed to evaluate the fiber architecture of other soft tissues, the organizational behavior of tendon under load has not been determined. The supraspinatus tendon (SST) of the rotator cuff is of particular interest for investigation due to its complex mechanical environment and corresponding inhomogeneity. In addition, SST injury occurs frequently with limited success in treatment strategies, illustrating the need for a better understanding of SST properties. Therefore, the objective of this study was to quantitatively evaluate the inhomogeneous tensile mechanical properties, fiber organization and fiber realignment under load of human SST utilizing a novel polarized light technique. Fiber distributions were found to become more aligned under load, particularly during the low stiffness toe-region, suggesting that fiber realignment may be partly responsible for observed nonlinear behavior. Fiber alignment was found to correlate significantly with mechanical parameters, providing evidence for strong structure-function relationships in tendon. Human SST exhibits complex, inhomogeneous mechanical properties and fiber distributions, perhaps due to its complex loading environment. Surprisingly, histological grade of degeneration did not correlate with mechanical properties. PMID:19544524

  20. CHARACTERIZATION OF TENSILE STRENGTH OF GLOVEBOX GLOVES

    SciTech Connect

    Korinko, P.; Chapman, G.

    2012-02-29

    A task was undertaken to compare various properties of different glovebox gloves, having various compositions, for use in gloveboxes at the Savannah River Site (SRS). One aspect of this project was to determine the tensile strength (TS) of the gloves. Longitudinal tensile samples were cut from 15 different gloves and tensile tested. The stress, load, and elongation at failure were determined. All of the gloves that are approved for glovebox use and listed in the glovebox procurement specification met the tensile and elongation requirements. The Viton{reg_sign} compound gloves are not listed in the specification, but exhibited lower tensile strengths than permissible based on the Butyl rubber requirements. Piercan Polyurethane gloves were the thinnest samples and exhibited the highest tensile strength of the materials tested.

  1. Tensile Test For Arboform Samples

    NASA Astrophysics Data System (ADS)

    Plavanescu (Mazurchevici), Simona; Quadrini, Fabrizio; Nedelcu, Dumitru

    2015-07-01

    Petroleum-based plastic materials constitute a major environmental problem due to their low biodegradability and accumulation in various environments. Therefore, searching for novel biodegradable plastics is received particular attention. Our studied material, "Liquid wood" produced from lignin, natural fibres and natural additives, is completely biodegradable in natural environment, in normal conditions. This paper presents the behaviour of Arboform and Arboform reinforced with Aramidic Fibers tensile test analysis. Experimental data show that the tensile strength reached an average value of 15.8 MPa, the modulus of elasticity after tests is 3513.3MPA for Arboform and for the reinforcement the tensile strength is 23.625MPa, the modulus of elasticity after tests is 3411.5MPA, the materials present a brittle behaviour. The high mechanical properties of newly developed material, better than of other ordinary plastics, recommend it as a potential environment-friendly substituent for synthetic plastics, which are present in all fields of activity.

  2. Silphenylene elastomers have high thermal stability and tensile strength

    NASA Technical Reports Server (NTRS)

    1969-01-01

    Two polymeric silphenylene ethers, when cured by reactions with ethyl silicates and metal salts at room temperature, form elastomers having excellent thermal stability and tensile properties. The highest tensile strength obtained in a reinforced elastomer was 2800 psi.

  3. Effect of iron-intermetallics and porosity on tensile and impact properties of aluminum-silicon-copper and aluminum-silicon-magnesium cast alloys

    NASA Astrophysics Data System (ADS)

    Ma, Zheyuan

    Aluminum-silicon (Al-Si) alloys are an important class of materials that constitute the majority of aluminum cast parts produced, due to their superior properties and excellent casting characteristics. Within this family of alloys, Al-Si-Cu and Al-Si-Mg cast alloys are frequently employed in automotive applications. The commercially popular 319 and 356 alloys, representing these two alloy systems, were selected for study in the present work, with the aim of investigating the effect of iron intermetallics and porosity on the alloy performance. This was carried out through a study of the tensile and impact properties, these being two of the important mechanical properties used in design calculations. Iron, through the precipitation of second phase intermetallic constituents, in particular the platelike beta-Al5FeSi phase, is harmful to the alloy properties. Likewise, gas- or shrinkage porosity in castings is also detrimental to the mechanical properties. By determining the optimum alloying, melt processing and solidification parameters (viz., Fe content, Sr modification and cooling rate) required to minimize the harmful effects of porosity and iron intermetallics, and studying their role on the fracture behavior, the fracture mechanism in the alloys could be determined. Castings were prepared from both industrial and experimental 319.2, B319.2 and A356.2 alloy melts, containing Fe levels of 0.2--1.0 wt%. Sr-modified (˜200 ppm) melts were also prepared for each alloy Fe level. The end-chilled refractory mold used provided directional solidification and a range of cooling rates (or dendrite arm spacings, DAS) within the same casting. Tensile and impact test samples machined from specimen blanks sectioned from the castings at various heights above the chill end provided DASs of 23--85mum. All samples were T6-heat-treated before testing. Tests were carried out employing Instron Universal and Instrumented Charpy testing machines. Optical microscopy, image analysis, SEM

  4. Effect of the addition of Mn on the tensile properties of a spray-formed and extruded Al-9Si-4Cu-1Fe alloy

    NASA Astrophysics Data System (ADS)

    Benetti, G. D.; Jorge, A. M., Jr.; Kiminami, C. S.; Botta, W. J.; Bolfarini, C.

    2009-01-01

    The microstructure and the tensile properties of a spray-formed and extruded Al- 9Si-4Cu-1Fe alloy were investigated. Manganese (0.3, 1, 2 in wt%) was added to the alloy to avoid the formation of the needle-like β-AlFeSi intermetallic phases that are highly detrimental to the alloy's ductility. The deposits were extruded at 623K with a n area reduction of 5 to 1. Small faceted dispersoids surrounding the equiaxial α-Al matrix, mainly in the form of silicon particles, were identified by SEM-EDS, as well as the Mn-containing α-Al15(Fe,Mn)3Si2 phase. The presence of the needle-like β-Al(Fe,Mn)Si was scanty, even with the lowest Mn content. The room temperature tensile tests of all the extruded alloys showed a significant increase in elongation to fracture when compared with the values observed fo r the as-spray formed deposits.This result can be ascribed to the elimination of porosity promoted by the extrusion process and to the smaller grain size of the extruded samples. PUBLISHER'S NOTE This article by Benetti et al was published in error, it was a duplicate of article 012114 which appears later in this volume, the duplicate PDF and references have been deleted. The missing article by S Jayalakshmi, E Fleury and D J Sordelet, which forms part of the section HYDROGEN IN METASTABLE ALLOYS, now appears at the end of the volume (012120).

  5. Effects of test environment and grain size on the tensile properties of L1 sub 2 -ordered (Co,Fe) sub 3 V alloys

    SciTech Connect

    Nishimura, C.; Liu, C.T.

    1991-01-01

    The influence of test environment, grain size, and heat treatment on the tensile properties and fracture behavior of L1{sub 2}-ordered (Co{sub 78}Fe{sub 22}){sub 3}V and (Co{sub 85}Fe{sub 15}){sub 3}V alloys was studied at room temperature. The tensile ductility depends strongly on test environments; the elongation decreases in the sequence of oxygen, vacuum, air, and distilled water. The loss in elongation is accompanied by a change in fracture mode from transgranular to intergranular. When tested in oxygen or vacuum, (Co{sub 78}Fe{sub 22}){sub 3}V specimens exhibited predominantly transgranular fracture, while (Co{sub 85}Fe{sub 15}){sub 3}V specimens exhibited essentially intergranular fracture. Grain refinement of (Co{sub 78}Fe{sub 22}){sub 3}V resulted in a ductility improvement in air, while such a beneficial effect of a grain refinement was not observed in (Co{sub 85}Fe{sub 15}){sub 3}V. These results suggest that: (1) (Co,Fe){sub 3}V alloys exhibit a moisture-induced hydrogen embrittlement and (2) grain boundaries are more intrinsically brittle in (Co{sub 85}Fe{sub 15}){sub 3}V than in (Co{sub 78}Fe{sub 22}){sub 3}V. The presence of a brittle hexagonal phase is suggested to be the reason for the observed grain-boundary brittleness in (Co{sub 85}Fe{sub 15}){sub 3}V. 29 refs., 6 figs., 2 tabs.

  6. Tensile and Fracture Properties of Cast and Forged Composite Synthesized by Addition of Al-Si Alloy to Magnesium

    NASA Astrophysics Data System (ADS)

    Nanjunda Swamy, H. M.; Nath, S. K.; Ray, S.

    2009-12-01

    Cast Mg-Al-Si composites synthesized by addition of Al-Si alloy containing 10, 15, and 20 wt pct of Si, in molten magnesium, to generate particles of Mg2Si by reaction between silicon and magnesium during stir casting has opened up the possibility to control the size of these particles. The microstructure of the cast composite consists of relatively dark polyhedral phase of Mg2Si and bright phase of β-Al12Mg17 along the boundary between dendrites of α-Mg solid solution. After hot forging at 350 °C, the microstructure has changed to relatively smaller sizes of β-Al12Mg17 and Mg2Si particles apart from larger grains surrounded by smaller grains due to dynamic recovery and recrystallization. Some of the Mg2Si particles crack during forging. In both the cast and forged composite, the Brinell hardness increases rapidly with increasing volume fraction of Mg2Si, but the hardness is higher in forged composites by about 100 BHN. Yield strength in cast composites improves over that of the cast alloy, but there is a marginal increase in yield strength with increasing Mg2Si content. In forged composites, there is significant improvement in yield strength with increasing Mg2Si particles and also over those observed in their cast counterpart. In cast composites, ultimate tensile strength (UTS) decreases with increasing Mg2Si content possibly due to increased casting defects such as porosity and segregation, which increases with increasing Mg2Si content and may counteract the strengthening effect of Mg2Si content. However, in forged composite, UTS increases with increasing Mg2Si content until 5.25 vol pct due to elimination of segregation and lowering of porosity, but at higher Mg2Si content of 7 vol pct, UTS decreases, possibly due to extensive cracking of Mg2Si particles. On forging, the ductility decreases in forged alloy and composites possibly due to the remaining strain and the forged microstructure. The initiation fracture toughness, J IC , decreases drastically in

  7. Effect of solvent/polymer infiltration and irradiation on microstructure and tensile properties of carbon nanotube yarns

    DOE PAGESBeta

    Hiremath, Nitilaksha; Lu, Xinyi; Evora, Maria Cecilia; Naskar, Amit; Mays, Jimmy; Bhat, Gajanan

    2016-07-29

    Recently carbon nanotube (CNT) yarns have been gaining importance as an approach to harvest the excellent properties of the CNTs. However, the properties of CNT yarns at this stage are well below the expected value. Investigation of the structure of CNT yarns and possible approaches to enhance the strength and modulus are reported. Scanning electron microscopy and focused ion beam imaging reveal the inherently porous structure and poor orientation, emphasizing the need to enhance packing of CNT bundles in the yarns for increased strength and modulus. Densification of CNT yarn by toluene or polystyrene increases the strength by 140 ormore » 172 % and modulus by 79 or 218 %, respectively, as compared to that of the pristine yarn. E-beam irradiation was investigated as a means to introduce crosslinking and enhanced internanotubes bonding to increase strength and modulus. However, the irradiation resulted in generation of defects and damages to the yarn contributing to reduction in strength and modulus. Raman spectroscopy studies on the irradiated samples reveal the change in bonding characteristics resulting in poor mechanical properties. As a result, denser packing of nanotubes and increased interaction without any damage is the key to improve the properties of CNT yarns.« less

  8. Psychometric Properties of the Acceptance and Action Questionnaire-II for Chinese College Students and Elite Chinese Athletes

    ERIC Educational Resources Information Center

    Zhang, Chun-Qing; Chung, Pak-Kwong; Si, Gangyan; Liu, Jing Dong

    2014-01-01

    The purpose of the present study was to examine the psychometric properties of the Chinese version of the Acceptance and Action Questionnaire-II (AAQ-II) across two samples of Chinese college students (n = 183 and n = 366) and a sample of elite Chinese athletes (n = 330). Exploratory and confirmatory factor analyses supported the existence of a…

  9. 12 CFR 1010.558 - Previously accepted state filings-notice of revocation rights on property report cover page.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 8 2014-01-01 2014-01-01 false Previously accepted state filings-notice of revocation rights on property report cover page. 1010.558 Section 1010.558 Banks and Banking BUREAU OF CONSUMER FINANCIAL PROTECTION LAND REGISTRATION (REGULATION J) Certification of Substantially Equivalent State Law § 1010.558 Previously...

  10. 12 CFR 1010.558 - Previously accepted state filings-notice of revocation rights on property report cover page.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 8 2013-01-01 2013-01-01 false Previously accepted state filings-notice of revocation rights on property report cover page. 1010.558 Section 1010.558 Banks and Banking BUREAU OF CONSUMER FINANCIAL PROTECTION LAND REGISTRATION (REGULATION J) Certification of Substantially Equivalent State Law § 1010.558 Previously...

  11. 24 CFR 1710.558 - Previously accepted state filings-notice of revocation rights on property report cover page.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Previously accepted state filings-notice of revocation rights on property report cover page. 1710.558 Section 1710.558 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR HOUSING-FEDERAL HOUSING...

  12. 32 CFR 37.540 - May I accept fully depreciated real property or equipment as cost sharing?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 1 2010-07-01 2010-07-01 false May I accept fully depreciated real property or equipment as cost sharing? 37.540 Section 37.540 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE DoD GRANT AND AGREEMENT REGULATIONS TECHNOLOGY INVESTMENT AGREEMENTS Pre-Award...

  13. Influence of the tensile strain rate on the mechanical properties and phase composition of VNS 9-Sh TRIP steel

    NASA Astrophysics Data System (ADS)

    Terent'ev, V. F.; Slizov, A. K.; Prosvirnin, D. V.; Sirotinkin, V. P.; Ashmarin, A. A.; Gol'dberg, M. A.

    2015-10-01

    The influence of the strain rate on the mechanical properties and the phase composition of a sheet VNS 9-Sh (23Kh15N5AM3-Sh) TRIP steel is studied during static tension. The strain rate is changed in the range from 8.3 × 10-5 to 25 × 10-3 s-1. The dependence of the mechanical properties on the strain rate is found to be nonlinear. The TRIP effect is most pronounced at a strain rate of (8.3-17) × 10-5 s-1. In this strain rate, the deformation martensite content increases significantly, from 50 to 87%, as is detected by X-ray diffraction.

  14. Influence of delta ferrite and dendritic carbides on the impact and tensile properties of a martensitic chromium steel

    NASA Astrophysics Data System (ADS)

    Schäfer, L.

    1998-10-01

    Martensitic chrome steels with a high content of chromium incline to form delta ferrite frequently accompanied by massive dendritic carbide precipitations. Both phases mostly influence the mechanical properties of this steel in countercurrent manner. The relatively soft delta ferrite causes an increase of ductility and toughness, whilst the brittle dendritic carbides decreases both. Both phases mostly decrease the strength of the steel. One or the other influence will be dominant in dependence of the quantitative relation of the two phases. This is the cause for very different statements in the literature. The dendritic carbides should be avoided using a cooling rate of more than 10 3 K/min after the austenitization, because this phase mostly impairs the mechanical properties of the steel. However, the delta ferrite without dendritic carbides can be tolerated mostly.

  15. Mechanical Strength and Failure Characteristics of Cast Mg-9 pctAl-1 pctZn Alloys Produced by a Heated-Mold Continuous Casting Process: Tensile Properties

    NASA Astrophysics Data System (ADS)

    Okayasu, Mitsuhiro; Takeuchi, Shuhei; Ohfuji, Hiroaki

    2014-11-01

    The mechanical properties and failure characteristics of a cast Mg alloy (AZ91: Mg-Al8.9-Zn0.6-Mn0.2) produced by a heated-mold continuous casting process (HMC) are investigated. In a modification of the original HMC process, the cooling of the liquid alloy by direct water spray is carried out in an atmosphere of high-purity argon gas. The HMC-AZ91 alloy exhibits excellent mechanical properties (high strength and high ductility) that are about twice as high as those for the same alloy produced by conventional gravity casting. The increased material strength and ductility of the HMC sample are attributed to nanoscale and microscale microstructural characteristics. The fine grains and tiny spherical eutectic structures ( e.g., Mg17Al12 and Al6Mn) distributed randomly in the matrix of the HMC alloy result in resistance to dislocation movement, leading to high tensile strength. Basal slip on (0001) planes in the relatively organized crystal orientation of the HMC alloy, as well as grain boundary sliding through tiny spherical eutectic structures, results in high ductility. Details of the failure mechanism under static loading in the HMC alloy are also discussed using failure models.

  16. Effect of yttrium additions on the tensile properties and hardness of an iron-nickel-chromium alloy. [LMFBR

    SciTech Connect

    Shah-Khan, M.Z.

    1981-10-01

    Results of the research work show that the addition of 0.1% yttrium does not significantly change the mechanical properties of the AL1 alloy with temperature (even though the yttrium-doped samples did show a slight increase in yield stress and hardness for tests above 700/sup 0/C); the room temperature strength of the undoped AL1 alloy increases upon annealing at temperatures above 600/sup 0/C; and the room temperature uniform and fracture strains of the undoped AL1 alloy decrease upon annealing at temperatures above 600/sup 0/C.

  17. Microstructure and tensile properties of neutron irradiated Cu and Cu sbnd 5Ni containing isotopically controlled boron

    NASA Astrophysics Data System (ADS)

    Muroga, T.; Watanabe, H.; Yoshida, N.; Kurishita, H.; Hamilton, M. L.

    1995-08-01

    Cu and Cu sbnd 5Ni dopwe with either natural boron (20% 10B) or isotopically enriched boron (91% 10B) were irradiated in FFTF/MOTA at 646 K to 6.3 dpa and 683 K to 4.9 dpa. The He/dpa ratio varied from 0.1 to 224. The dependence of irradiation-induced microstructures and mechanical properties (yield stress change and uniform elongation) on the helium level was examined. In pure Cu, the void size distribution changed from unimodal to bimodal with the increase of He/dpa ratio. The swelling peak occured at a He/dpa ratio of 5 to 10. In Cu sbnd 5Ni, the swelling rapidly decreased with He/dpa ratio. The yield stress change was well correlated with microstructural-based calculations describing contributions to hardening by voids and dislocations. Cavity formation and growth at grain boundaries resulted in enhanced grain boundary fracture and significant loss of elongation in the case of high He/dpa ratio. This effect, however, was small at fusion-relevant He/dpa ratio.

  18. Influence of liquid lead and lead-bismuth eutectic on tensile, fatigue and creep properties of ferritic/martensitic and austenitic steels for transmutation systems

    NASA Astrophysics Data System (ADS)

    Gorse, D.; Auger, T.; Vogt, J.-B.; Serre, I.; Weisenburger, A.; Gessi, A.; Agostini, P.; Fazio, C.; Hojna, A.; Di Gabriele, F.; Van Den Bosch, J.; Coen, G.; Almazouzi, A.; Serrano, M.

    2011-08-01

    In this paper, the tensile, fatigue and creep properties of the Ferritic/Martensitic (F/M) steel T91 and of the Austenitic Stainless (AS) Steel 316L in lead-bismuth eutectic (LBE) or lead, obtained in the different organizations participating to the EUROTRANS-DEMETRA project are reviewed. The results show a remarkable consistency, referring to the variety of metallurgical and surface state conditions studied. Liquid Metal Embrittlement (LME) effects are shown, remarkable on heat-treated hardened T91 and also on corroded T91 after long-term exposure to low oxygen containing Liquid Metal (LM), but hardly visible on passive or oxidized smooth T91 specimens. For T91, the ductility trough was estimated, starting just above the melting point of the embrittler ( TM,E = 123.5 °C for LBE, 327 °C for lead) with the ductility recovery found at 425 °C. LME effects are weaker on 316L AS steel. Liquid Metal Assisted Creep (LMAC) effects are reported for the T91/LBE system at 550 °C, and for the T91/lead system at 525 °C. Today, if the study of the LME effects on T91 and 316L in LBE or lead can be considered well documented, in contrast, complementary investigations are necessary in order to quantify the LMAC effects in these systems, and determine rigorously the threshold creep conditions.

  19. Effects of Oxides on Tensile and Charpy Impact Properties and Fracture Toughness in Heat Affected Zones of Oxide-Containing API X80 Linepipe Steels

    NASA Astrophysics Data System (ADS)

    Sung, Hyo Kyung; Sohn, Seok Su; Shin, Sang Yong; Oh, Kyung Shik; Lee, Sunghak

    2014-06-01

    This study is concerned with effects of complex oxides on acicular ferrite (AF) formation, tensile and Charpy impact properties, and fracture toughness in heat affected zones (HAZs) of oxide-containing API X80 linepipe steels. Three steels were fabricated by adding Mg and O2 to form oxides, and various HAZ microstructures were obtained by conducting HAZ simulation tests under different heat inputs. The no. of oxides increased with increasing amount of Mg and O2, while the volume fraction of AF present in the steel HAZs increased with increasing the no. of oxides. The strengths of the HAZ specimens were generally higher than those of the base metals because of the formation of hard microstructures of bainitic ferrite and granular bainite. When the total Charpy absorbed energy was divided into the fracture initiation and propagation energies, the fracture initiation energy was maintained constant at about 75 J at room temperature, irrespective of volume fraction of AF. The fracture propagation energy rapidly increased from 75 to 150 J and saturated when the volume fraction of AF exceeded 30 pct. At 253 K (-20 °C), the total absorbed energy increased with increasing volume fraction of AF, as the cleavage fracture was changed to the ductile fracture when the volume fraction of AF exceeded 45 pct. Thus, 45 vol pct of AF at least was needed to improve the Charpy impact energy, which could be achieved by forming a no. of oxides. The fracture toughness increased with increasing the no. of oxides because of the increased volume fraction of AF formed around oxides. The fracture toughness did not show a visible correlation with the Charpy absorbed energy at room temperature, because toughness properties obtained from these two toughness testing methods had different significations in view of fracture mechanics.

  20. 76 FR 35213 - AJT Mining Properties, Inc.; Notice of Preliminary Permit Application Accepted for Filing and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-16

    ... Energy Regulatory Commission AJT Mining Properties, Inc.; Notice of Preliminary Permit Application..., 2011, AJT Mining Properties, Inc., filed an application for a preliminary permit, pursuant to section 4...: Mr. Scott Willis, AJT Mining Properties, Inc., 5601 Tonsgard Court, Juneau, Alaska 99801; phone:...

  1. Effect of addition of thermally modified cowpea protein on sensory acceptability and textural properties of wheat bread and sponge cake.

    PubMed

    Campbell, Lydia; Euston, Stephen R; Ahmed, Mohamed A

    2016-03-01

    This paper investigates the sensory acceptability and textural properties of leavened wheat bread and sponge cake fortified with cow protein isolates that had been denatured and glycated by thermal treatment. Defatted cowpea flour was prepared from cow pea beans and the protein isolate was prepared (CPI) and thermally denatured (DCPI). To prepare glycated cowpea protein isolate (GCPI) the cowpea flour slurry was heat treated before isolation of the protein. CPI was more susceptible to thermal denaturation than GCPI as determined by turbidity and sulphydryl groups resulting in greater loss of solubility. This is attributed to the higher glycation degree and higher carbohydrate content of GCPI as demonstrated by glycoprotein staining of SDS PAGE gels. Water absorption of bread dough was significantly enhanced by DCPI and to a larger extent GCPI compared to the control, resulting in softer texture. CPI resulted in significantly increased crumb hardness in baked bread than the control whereas DCPI or GCPI resulted in significantly softer crumb. Bread fortified with 4% DCPI or GCPI was similar to control as regards sensory and textural properties whereas 4% CPI was significantly different, limiting its inclusion level to 2%. There was a trend for higher sensory acceptability scores for GCPI containing bread compared DCPI. Whole egg was replaced by 20% by GCPI (3.5%) in sponge cake without affecting the sensory acceptability, whereas CPI and DCPI supplemented cakes were significantly different than the control. PMID:26471676

  2. Effects of Rolling and Cooling Conditions on Microstructure and Tensile and Charpy Impact Properties of Ultra-Low-Carbon High-Strength Bainitic Steels

    NASA Astrophysics Data System (ADS)

    Sung, Hyo Kyung; Shin, Sang Yong; Hwang, Byoungchul; Lee, Chang Gil; Kim, Nack J.; Lee, Sunghak

    2011-07-01

    Six ultra-low-carbon high-strength bainitic steel plates were fabricated by controlling rolling and cooling conditions, and effects of bainitic microstructure on tensile and Charpy impact properties were investigated. The microstructural evolution was more critically affected by start cooling temperature and cooling rate than by finish rolling temperature. Bainitic microstructures such as granular bainites (GBs) and bainitic ferrites (BFs) were well developed as the start cooling temperature decreased or the cooling rate increased. When the steels cooled from 973 K or 873 K (700 °C or 600 °C) were compared under the same cooling rate of 10 K/s (10 °C/s), the steels cooled from 973 K (700 °C) consisted mainly of coarse GBs, while the steels cooled from 873 K (600 °C) contained a considerable amount of BFs having high strength, thereby resulting in the higher strength but the lower ductility and upper shelf energy (USE). When the steels cooled from 673 K (400 °C) at a cooling rate of 10 K/s (10 °C/s) or 0.1 K/s (0.1 °C/s) were compared under the same start cooling temperature of 873 K (600 °C), the fast cooled specimens were composed mainly of coarse GBs or BFs, while the slowly cooled specimens were composed mainly of acicular ferrites (AFs). Since AFs had small effective grain size and contained secondary phases finely distributed at grain boundaries, the slowly cooled specimens had a good combination of strength, ductility, and USE, together with very low energy transition temperature (ETT).

  3. Tensile properties of Haynes alloy 230 and Inconel 617 after long exposures to LiF-22CaF[sub 2] and vacuum at 1,093 K

    SciTech Connect

    Whittenberger, J.D. )

    1994-12-01

    As a part of a study of a space-based thermal energy storage system utilizing the latent heat of fusion of the eutectic salt LiF-20CaF[sub 2] (mole%), the two wrought Ni-base superalloys Haynes alloy 230 and Inconel 617 were subjected to molten salt, its vapor, and vacuum for periods as long as 10,000 h at 1,093 K. Following exposure, the microstructures were characterized, and samples from each superalloy were tensile tested between 77 and 1,200 K. Neither the structure nor mechanical properties revealed evidence for additional degradation due to exposures to the salt. Although some loss in tensile properties was noted, particularly at 77 K, this reduction could be ascribed to the influence of simple aging at 1,093 K.

  4. Sr effect on the microstructure and tensile properties of A357 aluminum alloy and Al{sub 2}O{sub 3}/SiC-A357 cast composites

    SciTech Connect

    Razaghian, A.; Emamy, M.; Najimi, A.A.; Ebrahimi, S.H. Seyed

    2009-11-15

    The effect of strontium as a modifier on the microstructures and tensile properties of two castable particulate metal matrix composites has been studied. The particulate metal matrix composites had similar matrix alloy (A357) but different reinforcing fine particles (silicon carbide and alumina). Results showed that the addition of 0.03% strontium makes a modest improvement to the yield strength, ultimate tensile strength and elongation percentage values, and the scatter of these properties, but makes a significant improvement to minimum strength and elongation results. Microstructural examinations by scanning electron microscope and energy dispersive spectroscopy analysis of metal matrix composites showed segregation of strontium on both the silicon carbide and alumina particles. Further results showed that the addition of higher strontium levels contributes to the over-modification of the eutectic silicon and promotes the formation of an Al-Si-Sr intermetallic compound on the particle/matrix interface.

  5. The Coding Properties of Lysine-accepting Transfer Ribonucleic Acids from Black-eyed Peas 1

    PubMed Central

    Hague, Donald R.; Kofoid, Eric C.

    1971-01-01

    Lysine-accepting transfer RNA from ungerminated and germinated embryo axes of black-eyed peas (Vigna sinensis L. Savi) was fractionated on benzoylated diethylaminoethyl cellulose and reverse phase Freon columns. Cochromatography indicated the presence of two similar lysyl transfer RNA fractions in each tissue. Ribosome binding studies revealed that the larger of the two fractions in each case is specific for the AAG codon, while the smaller one recognizes AAA and AAG. Possible implications of this difference in quantities of isoacceptors in translation of genetic information are discussed. PMID:16657787

  6. Tensile Properties of 17-7 PH and 12 MoV Stainless-Steel Sheet under Rapid-Heating and Constant-Temperature Conditions

    NASA Technical Reports Server (NTRS)

    Manning, Charles R., Jr.; Price, Howard L.

    1961-01-01

    Results are presented of rapid-heating tests of 17-7 PH and 12 MoV stainless-steel sheet heated to failure at temperature rates from about 1 F to 170 F per second under constant-load conditions. Yield and rupture strengths obtained from rapid-heating tests are compared with yield and tensile strengths obtained from short-time elevated-temperature tensile tests (30-minute exposure). A rate-temperature parameter was used to construct master curves from which yield and rupture stresses or temperatures can be predicted. A method for measuring strain by optical means is described.

  7. Peripheral substitution as a tool for tuning electron-accepting properties of phthalocyanine analogs in intramolecular charge transfer.

    PubMed

    Cidlina, Antonin; Novakova, Veronika; Miletin, Miroslav; Zimcik, Petr

    2015-04-21

    The intramolecular charge transfer (ICT), which is a pathway for excited state relaxation, was studied on the newly synthesized zinc(ii) complexes of tetrapyrazinoporphyrazines bearing one fixed donor (i.e., a dialkylamino substituent). The rest of the peripheral substituents on the core was designed with respect to their different electronic effects (OBu, neopentyl, StBu, COOBu). The photophysical (singlet oxygen and fluorescence quantum yields) and electrochemical (reduction potentials) properties were determined and compared within the series and with compounds that did not contain a donor moiety. The ICT efficiency correlated well with both the electron-deficient character of the core and the Hammett substituent constants σp. The most efficient ICT was observed for the core with the most electron-accepting substituent (COOBu), and the lowest ICT efficiency was detected for the least electron-deficient core (substituted by OBu). Titration of DMSO solutions of target compounds with H2SO4 indicated that basicity of the azomethine bridges was largely influenced by the character of the peripheral substituents while the dialkylamino donor center remained nearly unaffected. Furthermore, protonation of the donor nitrogen caused partial restoration of the fluorescence quantum yield (increase up to 90 times) due to blocking of ICT. The results implied that the ICT efficiency was strongly dependent on the electron-accepting properties of the core whose properties can be readily affected by suitable selection of peripheral substituents. PMID:25782137

  8. Tensile set behavior of Foley catheter balloons.

    PubMed

    Joseph, R; Ramesh, P; Sivakumar, R

    1999-01-01

    The removal of indwelling urinary balloon catheters from patients is usually associated with many problems. The problems such as balloon deflation failure; encrustations on balloons, eyes, and lumen; and catheter associated infections are widely discussed in the literature. The tensile set exhibited by the catheter balloon material could also play a role and further complicate the removal process. This article addresses this issue by comparing the tensile set behavior of the balloon material from three commercially available Foley catheters. The balloon materials were subjected to aging in synthetic urine at 37 degrees C for 28 days to simulate clinical conditions. The deflation time of catheter balloons aged in similar conditions were also measured. It was found that different brands of catheters exhibited statistically significant differences in their properties. The tensile set data of the aged samples could be correlated with the deflation time of the balloons. The clinical significance of the tensile set is also highlighted. PMID:10029146

  9. Physical properties and sixth graders' acceptance of an extruded ready-to-eat sweetpotato breakfast cereal

    NASA Technical Reports Server (NTRS)

    Dansby, M. Y.; Bovell-Benjamin, A. C.

    2003-01-01

    Extruded ready-to-eat breakfast cereals (RTEBCs) were made from varying levels of sweetpotato flour (SPF), whole-wheat bran (WWB), and extrusion cooking. Moisture, protein, and ash contents were lower in the 100% SPF than the 100% WWB. Carbohydrate, beta-carotene, and ascorbic acid contents were higher in the 100% SPF. Fat, thiamin, riboflavin contents, bulk densities, and the water absorption index were similar for the cereals. However, the expansion ratio was highest in the 100% SPF cereal. The 100% WWB had the lightest color and most fibrous morphology. Extruded RTEBC containing 100% SPF and 75%/25% SPF/WWB were well-liked and acceptable to sixth graders attending an elementary school in Auburn, Alabama, but the 100% WWB was unacceptable.

  10. Neutron irradiation effects on the density, tensile properties and microstructural changes in Hi-Nicalon™ and Sylramic™ SiC fibers

    NASA Astrophysics Data System (ADS)

    Osborne, M. C.; Hubbard, C. R.; Snead, L. L.; Steiner, D.

    1998-03-01

    Tensile results are presented for ceramic grade (cg) Nicalon™, Hi-Nicalon™ and Sylramic™ SiC fibers which have all been neutron irradiated in the high flux isotope reactor (HFIR) at damage levels of 0.1, 0.5, 2 and 5 dpa. Single fibers were tensile tested and the results were analyzed using Weibull statistics. Fiber axial displacements were measured with a laser micrometer which allowed for the determination of the tensile moduli. Density changes were measured with a gradient column. Transmission electron microscopy (TEM) was performed to assess microstructural damage and X-ray diffraction (XRD) was used to measure uniform strain, degree of crystallinity, average coherence length and root-mean-square microstrain. The physical and tensile results indicate that cg Nicalon™ and Hi-Nicalon™ are unstable in a neutron field. Both fiber types densify by 3-5% which would be detrimental to a composite's matrix cracking stress due to weakening or debonding of the interface. The Sylramic™ swells which is similar behavior to the monolithic SiC. The failure strength of the Sylramic™ drops by 50% after an irradiation temperature of 500°C which would have little effect on the matrix cracking condition of a composite. The Sylramic™ fiber strength decrease would significantly reduce the ultimate composite strength but the composite strength would remain above the matrix cracking strength such that the fibers may still potentially be viable for fusion applications.

  11. Consumer acceptability and sensory profile of cooked broccoli with mustard seeds added to improve chemoprotective properties.

    PubMed

    Ghawi, Sameer Khalil; Shen, Yuchi; Niranjan, Keshavan; Methven, Lisa

    2014-09-01

    Broccoli, a rich source of glucosinolates, is a commonly consumed vegetable of the Brassica family. Hydrolysis products of glucosinolates, isothiocyanates, have been associated with health benefits and contribute to the flavor of Brassica. However, boiling broccoli causes the myrosinase enzyme needed for hydrolysis to denature. In order to ensure hydrolysis, broccoli must either be mildly cooked or active sources of myrosinase, such as mustard seed powder, can be added postcooking. In this study, samples of broccoli were prepared in 6 different ways; standard boiling, standard boiling followed by the addition of mustard seeds, sous vide cooking at low temperature (70 °C) and sous vide cooking at higher temperature (100 °C) and sous vide cooking at higher temperature followed by the addition of mustard seeds at 2 different concentrations. The majority of consumers disliked the mildly cooked broccoli samples (70 °C, 12 min, sous vide) which had a hard and stringy texture. The highest mean consumer liking was for standard boiled samples (100 °C, 7 min). Addition of 1% mustard seed powder developed sensory attributes, such as pungency, burning sensation, mustard odor, and flavor. One cluster of consumers (32%) found mustard seeds to be a good complement to cooked broccoli; however, the majority disliked the mustard-derived sensory attributes. Where the mustard seeds were partially processed, doubling the addition to 2% led to only the same level of mustard and pungent flavors as 1% unprocessed seeds, and mean consumer liking remained unaltered. This suggests that optimization of the addition level of partially processed mustard seeds may be a route to enhance bioactivity of cooked broccoli without compromising consumer acceptability. PMID:25156799

  12. The influences of temperature and microstructure on the tensile properties of a CoCrFeMnNi high-entropy alloy

    SciTech Connect

    Otto, Frederik; Dlouhy, A.; Somsen, Ch.; Bei, Hongbin; Eggeler, G.; George, Easo P

    2013-01-01

    An equiatomic CoCrFeMnNi high-entropy alloy, which crystallizes in the face-centered cubic (FCC) crystal structure, was produced by arc melting and drop casting. The drop-cast ingots were homogenized, cold rolled, and recrystallized to obtain single-phase microstructures with three different grain sizes in the range 4~160 m. Quasi-static tensile tests were then performed at temperatures between 77 and 1073 K. Yield strength, ultimate tensile strength and ductility all increased with decreasing temperature. During the initial stages of plasticity (up to ~2% strain), deformation occurs by planar dislocation glide on the normal FCC slip system {111} 110 at all temperatures and grain sizes investigated. Undissociated 1/2 110 dislocations were observed, as were numerous stacking faults, which imply the dissociation of several of these dislocations into 1/6 112 Shockley partials. At later stages ( 20% strain), nanoscale deformation twins were observed after interrupted tests at 77 K, but not in specimens tested at room temperature where plasticity occurred exclusively by dislocations which organized into cells. Deformation twinning, by continually decreasing the mean free path of dislocations during tensile testing, produces a high degree of work hardening and a significant increase in the ultimate tensile strength. This increased work hardening prevents the early onset of necking instability and is a reason for the enhanced ductility observed at 77 K. A second way in which twinning can contribute to ductility is by providing an additional deformation mode to accommodate plasticity. However, it cannot explain the increase in yield strength with decreasing temperature in our high-entropy alloy since twinning was not observed in the early stages of plastic deformation. Since strong temperature dependencies of yield strength are also seen in binary FCC solid solution alloys, it may be an inherent solute effect, which needs further study.

  13. Making High-Tensile-Strength Amalgam Components

    NASA Technical Reports Server (NTRS)

    Grugel, Richard

    2008-01-01

    Structural components made of amalgams can be made to have tensile strengths much greater than previously known to be possible. Amalgams, perhaps best known for their use in dental fillings, have several useful attributes, including room-temperature fabrication, corrosion resistance, dimensional stability, and high compressive strength. However, the range of applications of amalgams has been limited by their very small tensile strengths. Now, it has been discovered that the tensile strength of an amalgam depends critically on the sizes and shapes of the particles from which it is made and, consequently, the tensile strength can be greatly increased through suitable choice of the particles. Heretofore, the powder particles used to make amalgams have been, variously, in the form of micron-sized spheroids or flakes. The tensile reinforcement contributed by the spheroids and flakes is minimal because fracture paths simply go around these particles. However, if spheroids or flakes are replaced by strands having greater lengths, then tensile reinforcement can be increased significantly. The feasibility of this concept was shown in an experiment in which electrical copper wires, serving as demonstration substitutes for copper powder particles, were triturated with gallium by use of a mortar and pestle and the resulting amalgam was compressed into a mold. The tensile strength of the amalgam specimen was then measured and found to be greater than 10(exp 4) psi (greater than about 69 MPa). Much remains to be done to optimize the properties of amalgams for various applications through suitable choice of starting constituents and modification of the trituration and molding processes. The choice of wire size and composition are expected to be especially important. Perusal of phase diagrams of metal mixtures could give insight that would enable choices of solid and liquid metal constituents. Finally, whereas heretofore, only binary alloys have been considered for amalgams

  14. Influence of oak maturation regimen on composition, sensory properties, quality, and consumer acceptability of cabernet sauvignon wines.

    PubMed

    Crump, Anna M; Johnson, Trent E; Wilkinson, Kerry L; Bastian, Susan E P

    2015-02-11

    Oak barrels have long been the preferred method for oak maturation of wine, but barrels contribute significantly to production costs, so alternate oak maturation regimens have been introduced, particularly for wines at lower price points. To date, few studies have investigated consumers' acceptance of wines made using non-traditional oak treatments. In this study, two Cabernet Sauvignon wines were aged using traditional (i.e., barrel) and/or alternative (i.e., stainless steel or plastic tanks and vats, with oak wood added) maturation regimens. Chemical and sensory analyses were subsequently performed to determine the influence on wine composition and sensory properties, that is, the presence of key oak-derived volatile compounds and perceptible oak aromas and flavor. The quality of a subset of wines was rated by a panel of 10 wine experts using a 20-point scoring system, with all wines considered technically sound. Consumer acceptance of wines was also determined. Hedonic ratings ranged from 5.7 to 5.9 (on a 9-point scale), indicating there was no significant difference in consumers' overall liking of each wine. However, segmentation based on individual liking scores identified three distinct clusters comprising consumers with considerably different wine preferences. These results justify wine producers' use of alternative oak maturation regimens to achieve wine styles that appeal to different segments of their target market. PMID:25584640

  15. Hypothesis for the Mechanism of Ascorbic Acid Activity in Living Cells Related to Its Electron-Accepting Properties.

    PubMed

    Pshenichnyuk, Stanislav A; Modelli, Alberto; Lazneva, Eleonora F; Komolov, Alexei S

    2016-05-01

    Electron-accepting properties, and in particular resonance dissociative electron attachment (DEA) to ascorbic acid (AA), are investigated by means of DEA spectroscopy in vacuo. The experimental features are assigned in silico and discussed in relation to expected dissociative electron transfer processes in vivo with the support of density functional theory calculations and the polarizable continuum model. It is shown that formation of the two most abundant AA metabolites in living cells, namely monodehydroascorbic acid and dehydroascorbic acid, can be stimulated by cellular electron transfer to AA under reductive conditions. Prooxidant effects caused by AA are suggested to be mediated by hydroxyl radicals formation via the DEA mechanism. The involvement of excited electronic states under UV-irradiation in plants could open additional DEA channels leading to specific AA activity forbidden under dark state conditions. PMID:27074645

  16. Tensile and shear strength of adhesives

    NASA Technical Reports Server (NTRS)

    Stibolt, Kenneth A.

    1990-01-01

    This experiment is conducted in a freshman-level course: Introduction to Engineering Materials. There are no prerequisites for the course although students should have some knowledge of basic algebra. The objectives are to tension and shear test adhesives and to determine the tensile and shear properties of adhesives. Details of equipment of procedure are given.

  17. Effect of natural fiber types and sodium silicate coated on natural fiber mat/PLA composites: Tensile properties and rate of fire propagation

    NASA Astrophysics Data System (ADS)

    Thongpin, C.; Srimuk, J.; hipkam, N.; Wachirapong, P.

    2015-07-01

    In this study, 3 types of natural fibres, i.e. jute, sisal and abaca, were plain weaved to fibre mat. Before weaving, the fibres were treated with 5% NaOH to remove hemi cellulose and lignin. The weaving was performed by hand using square wooden block fit with nails for weaving using one and two types of natural fibres as weft and warp fibre to produce natural fibre mat. The fibre mat was also impregnated in sodium silicate solution extracted from rich husk ash. The pH of the solution was adjusted to pH 7 using H2SO4 before impregnation. After predetermined time, sodium silicate was gelled and deposited on the mat. The fabric mat and sodium silicate coated mat were then impregnated with PLA solution to produce prepreg. Dried pepreg was laminated with PLA sheet using compressing moulding machine to obtain natural fibre mat/PLA composite. The composite containing abaca aligned in longitudinal direction with respect to tension force enhanced Young's modulus more than 300%. Fibre mat composites with abaca aligned in longitudinal direction also showed tensile strength enhancement nearly 400% higher than neat PLA. After coating with sodium silicate, the tensile modulus of the composites was found slightly increased. The silicate coating was disadvantage on tensile strength of the composite due to the effect of sodium hydroxide solution that was used as solvent for silicate extraction from rice husk ash. However, sodium silicate could retard rate of fire propagation about 50%compare to neat PLA and about 10% reduction compared to fibre mat composites without sodium silicate coated fibre mat.

  18. Strain rate dependence of the tensile properties of V-(4--5%)Cr-(4--5%)Ti irradiated in EBR-II and HFBR

    SciTech Connect

    Zinkle, S.J.; Snead, L.L.; Robertson, J.P.; Rowcliffe, A.F.

    1998-03-01

    Elevated temperature tensile tests performed on V-(405)Cr-(4-5)Ti indicate that the yield stress increases with increasing strain rate for irradiation and test temperatures near 200 C, and decreases with increasing strain rate for irradiation and test temperatures near 400 C. This observation is in qualitative agreement with the temperature-dependent strain rate effects observed on unirradiated specimens, and implies that some interstitial solute remains free to migrate in irradiated specimens. Additional strain rate data at different temperatures are needed.

  19. Tensile properties of HK31XA-H24 magnesium-alloy sheet under rapid-heating conditions and constant elevated temperatures

    NASA Technical Reports Server (NTRS)

    Gibbs, Thomas W

    1956-01-01

    Specimens of HK31XA-H24 magnesium-alloy sheet from an experimental batch were heated to failure at nominal temperature rates from 0.2 F to 100 F per second under constant-load conditions. Rapid-heating yield and rupture stresses are presented and compared with the yield and ultimate stresses from elevated-temperature tensile stress-strain tests for 1/2-hour exposure. Linear temperature-rate parameters were used to correlate rapid-heating results by constructing master curves which can be used for predicting yield stresses and temperatures and for estimating rupture stresses and temperatures.

  20. Quantitative and qualitative variation of fat in model vanilla custard desserts: effects on sensory properties and consumer acceptance.

    PubMed

    Tomaschunas, Maja; Köhn, Ehrhard; Bennwitz, Petra; Hinrichs, Jörg; Busch-Stockfisch, Mechthild

    2013-06-01

    The effects of variation in fat content (0.1% to 15.8%) and type of fat, using different types of milk, dairy cream, or vegetable fat cream, on sensory characteristics and consumer acceptance of starch-based vanilla model custards were studied. Descriptive analysis with trained panelists and consumer testing with untrained assessors were applied. Descriptive data were related to hedonic data using principal component analysis to determine drivers of liking and disliking. Results demonstrated an increasing effect of fat concerning visual and oral thickness, creamy flavor, and fat-related texture properties, as well as a decreasing effect concerning yellow color and surface shine. A lack of fat caused moderate intensities in pudding-like flavor attributes and an intensive jelly texture. Adding a vegetable fat cream led to lower intensities in attributes yellow color, cooked flavor, thick, and jelly texture, whereas intensities in vegetable fat flavor and fat-related texture properties increased. All consumers favored custards with medium fat contents, being high in pudding-like and vegetable fat flavor as well as in fat-related texture attributes. Nonfat custards were rejected due to jelly texture and moderate intensities in pudding-flavor attributes. High-fat samples were liked by some consumers, but their high intensities in thickness, white color, and creamy flavor also drove disliking for others. PMID:23772708

  1. The effect of low dose irradiation on the impact fracture energy and tensile properties of pure iron and two ferritic martensitic steels

    NASA Astrophysics Data System (ADS)

    Belianov, I.; Marmy, P.

    1998-10-01

    Two batches of subsize V-notched impact bend specimens and subsize tensile specimens have been irradiated in the Saphir test reactor of the Paul Scherrer Institute (PSI). The first batch of specimen has been irradiated at 250°C to a dose of 2.65 × 10 19 n/cm 2 (0.042 dpa) and the second batch has been irradiated at 400°C to a dose of 8.12 × 10 19 n/cm 2 (0.13 dpa). Three different materials in three different microstructures were irradiated: pure iron and two ferritic steels, the alloy MANET 2 and a low activation composition CETA. The results of the impact tests and of the corresponding tensile tests are presented. Despite the very low neutron dose, a significant shift of the ductile to brittle transition temperature (DBTT) is observed. The influence of the test temperature on the impact energy is discussed for the irradiated and unirradiated conditions, with special emphasis on the microstructure.

  2. Tensile testing apparatus

    NASA Technical Reports Server (NTRS)

    Blackburn, L. B.; Ellingsworth, J. R. (Inventor)

    1985-01-01

    An improved mechanical extensometer is described for use with a constant load creep test machine. The dead weight of the extensometer is counterbalanced by two pairs of weights connected through a pulley system and to rod extension and leading into the furnace where the test sample is undergoing elevated temperature (above 500 F.) tensile testing. Novel gripper surfaces, conical tip and flat surface are provided in each sampling engaging platens to reduce the grip pressure normally required for attachment of the extensometer to the specimen and reduce initial specimen bending normally associated with foil-gage metal testing.

  3. Tensile testing apparatus

    NASA Astrophysics Data System (ADS)

    Blackburn, L. B.; Ellingsworth, J. R.

    1985-08-01

    An improved mechanical extensometer is described for use with a constant load creep test machine. The dead weight of the extensometer is counterbalanced by two pairs of weights connected through a pulley system and to rod extension and leading into the furnace where the test sample is undergoing elevated temperature (above 500 F.) tensile testing. Novel gripper surfaces, conical tip and flat surface are provided in each sampling engaging platens to reduce the grip pressure normally required for attachment of the extensometer to the specimen and reduce initial specimen bending normally associated with foil-gage metal testing.

  4. Micro-tensile testing system

    DOEpatents

    Wenski, Edward G.

    2006-01-10

    A micro-tensile testing system providing a stand-alone test platform for testing and reporting physical or engineering properties of test samples of materials having thicknesses of approximately between 0.002 inch and 0.030 inch, including, for example, LiGA engineered materials. The testing system is able to perform a variety of static, dynamic, and cyclic tests. The testing system includes a rigid frame and adjustable gripping supports to minimize measurement errors due to deflection or bending under load; serrated grips for securing the extremely small test sample; high-speed laser scan micrometers for obtaining accurate results; and test software for controlling the testing procedure and reporting results.

  5. Micro-tensile testing system

    DOEpatents

    Wenski, Edward G.

    2007-08-21

    A micro-tensile testing system providing a stand-alone test platform for testing and reporting physical or engineering properties of test samples of materials having thicknesses of approximately between 0.002 inch and 0.030 inch, including, for example, LiGA engineered materials. The testing system is able to perform a variety of static, dynamic, and cyclic tests. The testing system includes a rigid frame and adjustable gripping supports to minimize measurement errors due to deflection or bending under load; serrated grips for securing the extremely small test sample; high-speed laser scan micrometers for obtaining accurate results; and test software for controlling the testing procedure and reporting results.

  6. Micro-tensile testing system

    DOEpatents

    Wenski, Edward G.

    2007-07-17

    A micro-tensile testing system providing a stand-alone test platform for testing and reporting physical or engineering properties of test samples of materials having thicknesses of approximately between 0.002 inch and 0.030 inch, including, for example, LiGA engineered materials. The testing system is able to perform a variety of static, dynamic, and cyclic tests. The testing system includes a rigid frame and adjustable gripping supports to minimize measurement errors due to deflection or bending under load; serrated grips for securing the extremely small test sample; high-speed laser scan micrometers for obtaining accurate results; and test software for controlling the testing procedure and reporting results.

  7. High-temperature low-cycle fatigue and tensile properties of Hastelloy X and alloy 617 in air and HTGR-helium

    SciTech Connect

    Strizak, J.P.; Brinkman, C.R.; Rittenhouse, P.L.

    1981-01-01

    Results of strain controlled fatigue and tensile tests are presented for two nickel base solution hardened alloys which are reference structural alloys for use in several high temperature gas cooled reactor concepts. These alloys, Hastelloy X Inconel 617, were tested at temperatures ranging from room temperature to 871/sup 0/C in air and impure helium. Materials were tested in the solution annealed as well as in the pre-aged condition where aging consisted of isothermal exposure at one of several temperatures for periods of up to 20,000 h. Comparisons are also given between the strain controlled fatigue lives of these alloys and several other commonly used alloys all tested at 538/sup 0/C.

  8. Tensile properties of vanadium-base alloys irradiated in the Fusion-1 low-temperature experiment in the BOR-60 reactor

    SciTech Connect

    Tsai, H.; Gazda, J.; Nowicki, L.J.; Billone, M.C.; Smith, D.L.

    1998-09-01

    The irradiation has been completed and the test specimens have been retrieved from the lithium-bonded capsule at the Research Institute of Atomic Reactors (RIAR) in Russia. During this reporting period, the Argonne National Laboratory (ANL) tensile specimens were received from RIAR and initial testing and examination of these specimens at ANL has been completed. The results, corroborating previous findings showed a significant loss of work hardening capability in the materials. There appears to be no significant difference in behavior among the various heats of vanadium-base alloys in the V-(4-5)Cr-(4-5)Ti composition range. The variations in the preirradiation annealing conditions also produced no notable differences.

  9. Tensile and fracture toughness properties of the nanostructured oxide dispersion strengthened ferritic alloy 13Cr-1W-0.3Ti-0.3Y 2O 3

    NASA Astrophysics Data System (ADS)

    Eiselt, Ch. Ch.; Klimenkov, M.; Lindau, R.; Möslang, A.; Odette, G. R.; Yamamoto, T.; Gragg, D.

    2011-10-01

    The realization of fusion power as an attractive energy source requires advanced structural materials that can cope with ultra-severe thermo-mechanical loads and high neutron fluxes experienced by fusion power plant components, such as the first wall, divertor and blanket structures. Towards this end, two variants of a 13Cr-1W-0.3Ti-0.3Y 2O 3 reduced activation ferritic (RAF-) ODS steel were produced by ball milling phase blended Fe-13Cr-1W, 0.3Y 20 3 and 0.3Ti powders in both argon and hydrogen atmospheres. The milled powders were consolidated by hot isostatic pressing (HIP). The as-HIPed alloys were then hot rolled into 6 mm plates. Microstructural, tensile and fracture toughness characterization of the hot rolled alloys are summarized here and compared to results previously reported for the as-HIPed condition.

  10. Glycoluril-tetrathiafulvalene molecular clips: on the influence of electronic and spatial properties for binding neutral accepting guests.

    PubMed

    Cotelle, Yoann; Hardouin-Lerouge, Marie; Legoupy, Stéphanie; Alévêque, Olivier; Levillain, Eric; Hudhomme, Piétrick

    2015-01-01

    Glycoluril-based molecular clips incorporating tetrathiafulvalene (TTF) sidewalls have been synthesized through different strategies with the aim of investigating the effect of electrochemical and spatial properties for binding neutral accepting guests. We have in particular focused our study on the spacer extension in order to tune the intramolecular TTF···TTF distance within the clip and, consequently, the redox behavior of the receptor. Carried out at different concentrations in solution, electrochemical and spectroelectrochemical experiments provide evidence of mixed-valence and/or π-dimer intermolecular interactions between TTF units from two closed clips. The stepwise oxidation of each molecular clip involves an electrochemical mechanism with three one-electron processes and two charge-coupled chemical reactions, a scheme which is supported by electrochemical simulations. The fine-tunable π-donating ability of the TTF units and the cavity size allow to control binding interaction towards a strong electron acceptor such as tetrafluorotetracyanoquinodimethane (F4-TCNQ) or a weaker electron acceptor such as 1,3-dinitrobenzene (m-DNB). PMID:26199657

  11. Glycoluril–tetrathiafulvalene molecular clips: on the influence of electronic and spatial properties for binding neutral accepting guests

    PubMed Central

    Cotelle, Yoann; Hardouin-Lerouge, Marie; Legoupy, Stéphanie; Alévêque, Olivier

    2015-01-01

    Summary Glycoluril-based molecular clips incorporating tetrathiafulvalene (TTF) sidewalls have been synthesized through different strategies with the aim of investigating the effect of electrochemical and spatial properties for binding neutral accepting guests. We have in particular focused our study on the spacer extension in order to tune the intramolecular TTF···TTF distance within the clip and, consequently, the redox behavior of the receptor. Carried out at different concentrations in solution, electrochemical and spectroelectrochemical experiments provide evidence of mixed-valence and/or π-dimer intermolecular interactions between TTF units from two closed clips. The stepwise oxidation of each molecular clip involves an electrochemical mechanism with three one-electron processes and two charge-coupled chemical reactions, a scheme which is supported by electrochemical simulations. The fine-tunable π-donating ability of the TTF units and the cavity size allow to control binding interaction towards a strong electron acceptor such as tetrafluorotetracyanoquinodimethane (F4-TCNQ) or a weaker electron acceptor such as 1,3-dinitrobenzene (m-DNB). PMID:26199657

  12. Potentially acceptable substitutes for the chlorofluorocarbons: properties and performance features of HFC-134a, HCFC-123, and HCFC-141b

    NASA Astrophysics Data System (ADS)

    Sukornick, B.

    1989-05-01

    Potentially acceptable substitutes are known for CFC-11 and CFC-12-the most important Chlorofluorocarbons. HFC-134a could replace CFC-12 in airconditioning and refrigeration and both HCFC-123 and HCFC-141b show promise as CFC-11 substitutes. The replacement molecules all have significantly reduced greenhouse and ozone depletion potentials compared to their fully halogenated counterparts. HCFC-123 is theoretically a less efficient blowing agent than CFC-11, but 141b is more efficient. Results from experimental foaming tests confirm these relationships and show that initial insulating values are slightly lower for 141b and 123 than 11. Both substitutes are nonflammable liquids. Based on its physical properties, HFC-134a is an excellent replacement candidate for CFC-12. In addition, it is more thermally stable than CFC-12. A new family of HFC-134a compatible lubricant oils will be required. The estimated coefficient of performance (COP) of 134a is 96 98% that of CFC-12. Subacute toxicity tests show HFC-134a to have a low order of toxicity. HCFC-123 reveals no serious side effects at a concentration of 0.1% in subchronic tests and the inhalation toxicity of 141b is lower than that of CFC-11 based on a 6-h exposure. Chronic tests on all the new candidates will have to be completed for large-scale commercial use. Allied-Signal is conducting process development at a highly accelerated pace, and we plan to begin commercialization of substitutes within 5 years.

  13. Potentially acceptable substitutes for the chlorofluorocarbons: Properties and performance features of HFC-134a, HCFC-123, and HCFC-141b

    SciTech Connect

    Sukornick, B. )

    1989-05-01

    Potentially acceptable substitutes are known for CFC-11 and CFC-12 - the most important chlorofluorocarbons. HFC-134a could replace CFC-12 in air-conditioning and refrigeration and both HCFC-123 and HCFC-141b show promise as CFC-11 substitutes. The replacement molecules all have significantly reduced greenhouse and ozone depletion potentials compared to their fully halogenated counterparts. HCFC-123 is theoretically a less efficient blowing agent than CFC-11, but 141b is more efficient. Results from experimental foaming tests confirm these relationships and show that initial insulating values are slightly lower for 141 b and 123 than 11. Both substitutes are nonflammable liquids. Based on its physical properties, HFC-134a is an excellent replacement candidate for CFC-12. In addition, it is more thermally stable than CFC-12. A new family of HFC-134a compatible lubricant oils will be required. The estimated coefficient of performance (COP) of 134a is 96-98% that of CFC-12. Subacute toxicity tests show HFC-134a to have a low order of toxicity. HCFC-123 reveals no serious side effects at a concentration of 0.1% in subchronic tests and the inhalation toxicity of 141b is lower than that of CFC-11 based on a 6-h exposure. Chronic tests on all the new candidates will have to be completed for large-scale commercial use. Allied-Signal is conducting process development at a highly accelerated pace, and they plan to begin commercialization of substitutes within 5 years.

  14. Elevated Temperature Tensile Tests on DU–10Mo Rolled Foils

    SciTech Connect

    Schulthess, Jason

    2014-09-01

    Tensile mechanical properties for uranium-10 wt.% molybdenum (U–10Mo) foils are required to support modeling and qualification of new monolithic fuel plate designs. It is expected that depleted uranium-10 wt% Mo (DU–10Mo) mechanical behavior is representative of the low enriched U–10Mo to be used in the actual fuel plates, therefore DU-10Mo was studied to simplify material processing, handling, and testing requirements. In this report, tensile testing of DU-10Mo fuel foils prepared using four different thermomechanical processing treatments were conducted to assess the impact of foil fabrication history on resultant tensile properties.

  15. Influence of long-term annealing on tensile properties and fracture of near-{alpha} titanium alloy Ti-6Al-2.75Sn-4Zr-0.4Mo-0.45Si

    SciTech Connect

    Leyens, C.; Peters, M.; Weinem, D.; Kaysser, W.A.

    1996-06-01

    Long-term exposure at 600 C of the near-alpha titanium alloy Ti-6Al-2.75Sn-4Zr-0.4Mo-0.45Si (TIMETAL 1100) influences tensile properties and fracture morphology due to microstructural changes by aging as well as environmentally induced effects. The influences of aging and oxygen penetration on the subsurface of the alloy were evaluated individually. Metallographic investigations, microhardness measurements, and Auger electron spectroscopy (AES) were performed to examine the oxygen-affected zone. Whereas ultimate tensile stress (UTS) and 0.2 pct yield stress (YS) are mainly influenced by aging at 600 C up to 1,000 hours in bimodal and lamellar microstructures, ductility sensitivity depends on oxygen embrittlement of the subsurface zone. Hereafter, little strain cracks are initiated which rapidly penetrate into the unaffected material. Fracture morphology which was investigated by scanning electron microscopy changes little during exposure. Ductile fracture exhibiting honeycomb morphology was observed on bimodal microstructure and interlamellar fracture with little ductile portion on lamellar microstructure. The oxygen-penetrated zone fails by brittle fracture.

  16. Improved Tensile Test for Ceramics

    NASA Technical Reports Server (NTRS)

    Osiecki, R. A.

    1982-01-01

    For almost-nondestructive tensile testing of ceramics, steel rod is bonded to sample of ceramic. Assembly is then pulled apart in conventional tensile-test machine. Test destroys only shallow surface layer which can be machined away making specimen ready for other uses. Method should be useful as manufacturing inspection procedure for low-strength brittle materials.

  17. Electrothermal fracturing of tensile specimens

    NASA Technical Reports Server (NTRS)

    Blinn, H. O.; Hanks, J. G.; Perkins, H. P.

    1970-01-01

    Pulling device consisting of structural tube, connecting rod, spring-loaded nuts, loading rod, heating element, and three bulkheads fractures tensile specimens. Alternate heating and cooling increases tensile loading by increments until fracturing occurs. Load cell or strain gage, applied to pulling rod, determines forces applied.

  18. 41 CFR 102-75.1290 - What happens if the landholding agency requesting the property does not promptly accept custody...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... System (Continued) FEDERAL MANAGEMENT REGULATION REAL PROPERTY 75-REAL PROPERTY DISPOSAL Screening of Federal Real Property § 102-75.1290 What happens if the landholding agency requesting the property...

  19. Hydration dependent viscoelastic tensile behavior of cornea.

    PubMed

    Hatami-Marbini, Hamed

    2014-08-01

    The cornea is a protective transparent connective tissue covering the front of the eye. The standard uniaxial tensile experiments are among the most popular techniques for investigating biomechanical properties of the cornea. This experimental method characterizes the stress-strain response of corneal strips immersed in a bathing solution. In the present study, the important roles of corneal hydration on tensile viscoelastic properties were investigated. The thickness was used as a surrogate for hydration and uniaxial tensile experiments were performed on bovine corneal samples with four different average thickness (hydration), i.e., 1100 μm (4.87 mg water/mg dry tissue), 900 μm (4.13 mg water/mg dry tissue), 700 μm (3.20 mg water/mg dry tissue), and 500 μm (1.95 mg water/mg dry tissue). The samples were immersed in mineral oil in order to prevent their swelling during the experiments. A quasilinear viscoelastic (QLV) model was used to analyze the experimental measurements and determine viscoelastic material constants. It was observed that both maximum and equilibrium (relaxed) stresses were exponentially increased with decreasing tissue thickness (hydration). Furthermore, the QLV model successfully captured the corneal viscoelastic response with an average R (2) value greater than 0.99. Additional experiments were conducted in OBSS in order to confirm that these significant changes in viscoelastic properties were because of corneal hydration and not the bathing solution. The findings of this study suggest that extra care must be taken in interpreting the results of earlier uniaxial tensile testings and their correspondence to the corneal biomechanical properties. PMID:24668183

  20. Simulation of the Elastic and Ultimate Tensile Properties of Diamond, Graphene, Carbon Nanotubes, and Amorphous Carbon Using a Revised ReaxFF Parametrization.

    PubMed

    Jensen, Benjamin D; Wise, Kristopher E; Odegard, Gregory M

    2015-09-17

    In light of the enduring interest in using nanostructured carbon materials as reinforcing elements in composite materials, there is a significant need for a reliable computational tool capable to predict the mechanical properties, both elastic properties and properties at the point of fracture, in large-scale atomistic simulations. A revised version of the ReaxFF reactive force field parametrization for carbon, ReaxFFC-2013, was recently published and is notable because of the inclusion of density functional theory (DFT)-derived mechanical data for diamond and graphite in the fitting set. The purpose of the present work is to assess the accuracy of this new force field for predicting the mechanical properties for several allotropes of carbon, both in the elastic regime and during fracture. The initial discussion focuses on the performance of ReaxFFC-2013 for diamond and graphene, the two carbon forms for which mechanical properties were included in the parametrization data set. After it is established that simulations conducted with the new force field yield results that agree well with DFT and experimental data for most properties of interest, its transferability to amorphous carbon and carbon nanotubes is explored. ReaxFFC-2013 is found to produce results that, for the most part, compare favorably with available experimental data for single and multiwalled nanotubes and for amorphous carbon models prepared over a range of densities. Although there is opportunity for improvement in some predicted properties, the ReaxFFC-2013 parametrization is shown to generally perform well for each form of carbon and to compare favorably with DFT and experimental data. PMID:26315717