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Sample records for 6061-t6 aluminum matrix

  1. Mechanical shielding reduces weld surface cracking in 6061 T6 aluminum

    NASA Technical Reports Server (NTRS)

    Hill, J. E.

    1968-01-01

    Mechanical shield of high melting point material protects 6061-T6 aluminum welded with high frequency ac tungsten arc equipment. It is held in place around the weld bead area and eliminates heat check cracks.

  2. The corrosion protection of 6061-T6 aluminum by a polyurethane-sealed anodized coat

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1990-01-01

    The corrosion protection of 6061-T6 anodized aluminum afforded by a newly patented polyurethane seal was studied using the ac impedance technique. Values of the average corrosion rates over a 27-day exposure period in 3.5 percent NaCl solutions at pH 5.2 and pH 9.5 compared very favorably for Lockheed-prepared polyurethane-sealed and dichromate-sealed coats of the same thickness. Average corrosion rates for both specimens over the first 7 days of exposure compared well with those for a hard anodized, dichromate-sealed coat, but rose well above those for the hard anodized coat over the entire 27-day period. This is attributed both to the greater thickness of the hard anodized coat, and possibly to its inherently better corrosion protective capability.

  3. Cavitation pitting and erosion of aluminum 6061-T6 in mineral oil water

    NASA Technical Reports Server (NTRS)

    Rao, B. C. S.; Buckley, D. H.

    1983-01-01

    Cavitation erosion studies of aluminum 6061-T6 in mineral oil and in ordinary tap water are presented. The maximum erosion rate (MDPR, or mean depth of penetration rate) in mineral oil was about four times that in water. The MDPR in mineral oil decreased continuously with time, but the MDPR in water remained approximately constant. The cavitation pits in mineral oil were of smaller diameter and depth than the pits in water. Treating the pits as spherical segments, we computed the radius r of the sphere. The logarithm of h/a, where h is the pit depth and 2a is the top width of the pit, was linear when plotted against the logarithm of 2r/h - 1.

  4. Characteristics of laser beam welds of age-hardenable 6061-T6 aluminum alloy

    NASA Astrophysics Data System (ADS)

    Hirose, Akio; Kobayashi, Kojiro F.

    2003-03-01

    Laser beam welding is attractive for joining age-hardenable aluminum alloys, because its low over-all heat input results in a narrow weld heat affected zone (HAZ), where softening caused by dissolution of age precipitates occurs. In the present work, 1mm-thick 6061-T6 aluminum alloy plates were welded using a 2.5 kW CO2 laser and it was experimentally proved that the width of the softened region in the laser beam weld was less than 1/7 that of a TIG weld. Moreover the hardness in the softened region of the laser beam weld was found to be almost fully recovered to the base metal hardness by applying a post-weld aging treatment at 443 K for 28.8 ks without solution annealing unlike the TIG weld. These results characterize the advantage of laser beam welding in joining of the age-hardenable aluminum alloy as compared with the conventional arc welding. The hardness distributions in the HAZ were theoretically evaluated based on kinetic equations describing the dissolution of hardening β' (Mg2Si) precipitates and the precipitation of non-hardening β' (Mg2Si) precipitates during the weld thermal cycles to quantitatively prove above mentioned advantageous characteristics of laser beam welding.

  5. Experiments and simulation for 6061-T6 aluminum alloy resistance spot welded lap joints

    NASA Astrophysics Data System (ADS)

    Florea, Radu Stefanel

    This comprehensive study is the first to quantify the fatigue performance, failure loads, and microstructure of resistance spot welding (RSW) in 6061-T6 aluminum (Al) alloy according to welding parameters and process sensitivity. The extensive experimental, theoretical and simulated analyses will provide a framework to optimize the welding of lightweight structures for more fuel-efficient automotive and military applications. The research was executed in four primary components. The first section involved using electron back scatter diffraction (EBSD) scanning, tensile testing, laser beam profilometry (LBP) measurements, and optical microscopy(OM) images to experimentally investigate failure loads and deformation of the Al-alloy resistance spot welded joints. Three welding conditions, as well as nugget and microstructure characteristics, were quantified according to predefined process parameters. Quasi-static tensile tests were used to characterize the failure loads in specimens based upon these same process parameters. Profilometer results showed that increasing the applied welding current deepened the weld imprints. The EBSD scans revealed the strong dependency between the grain sizes and orientation function on the process parameters. For the second section, the fatigue behavior of the RSW'ed joints was experimentally investigated. The process optimization included consideration of the forces, currents, and times for both the main weld and post-heating. Load control cyclic tests were conducted on single weld lap-shear joint coupons to characterize the fatigue behavior in spot welded specimens. Results demonstrate that welding parameters do indeed significantly affect the microstructure and fatigue performance for these welds. The third section comprised residual strains of resistance spot welded joints measured in three different directions, denoted as in-plane longitudinal, in-plane transversal, and normal, and captured on the fusion zone, heat affected zone

  6. Erosion of aluminum 6061-T6 under cavitation attack in mineral oil and water

    NASA Technical Reports Server (NTRS)

    Rao, B. C. S.; Buckley, D. H.

    1985-01-01

    Studies of the erosion of aluminum 6061-T6 under cavitation attack in distilled water, ordinary tap water and a viscous mineral oil are presented. The mean depth of penetration for the mineral oil was about 40 percent of that for water at the end of a 40 min test. The mean depth of penetration and its rate did not differ significantly for distilled and tap water. The mean depth of penetration rate for both distilled and tap water increased to a maximum and then decreased with test duration, while that for mineral oil had a maximum during the initial period. The ratio h/2a of the pit depth h to the pit diameter 2a varied from 0.04 to 0.13 in water and from 0.06 to 0.20 in mineral oil. Scanning electron microscopy indicates that the pits are initially formed over the grain boundaries and precipitates while the surface grains are deformed under cavitation attack.

  7. CO2 laser beam welding of 6061-T6 aluminum alloy thin plate

    NASA Astrophysics Data System (ADS)

    Hirose, Akio; Kobayashi, Kojiro F.; Todaka, Hirotaka

    1997-12-01

    Laser beam welding is an attractive welding process for age-hardened aluminum alloys, because its low heat input minimizes the width of weld fusion and heat-affected zones (HAZs). In the present work, 1-mm-thick age-hardened Al-Mg-Si alloy, 6061-T6, plates were welded with full penetration using a 2.5-kW CO2 laser. Fractions of porosity in the fusion zones were less than 0.05 pct in bead-on-plate welding and less than 0.2 pct in butt welding with polishing the groove surface before welding. The width of a softened region in the-laser beam welds was less than 1/4 times that of a tungsten inert gas (TIG) weld. The softened region is caused by reversion of strengthening β″ (Mg2Si) precipitates due to weld heat input. The hardness values of the softened region in the laser beam welds were almost fully recovered to that of the base metal after an artificial aging treatment at 448 K for 28.8 ks without solution annealing, whereas those in the TIG weld were not recovered in a partly reverted region. Both the bead-on-plate weld and the butt weld after the postweld artificial aging treatment had almost equivalent tensile strengths to that of the base plate.

  8. Laser peening without coating on aluminum alloy Al-6061-T6 using low energy Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Sathyajith, S.; Kalainathan, S.; Swaroop, S.

    2013-02-01

    The present study investigates the effect of laser peening without coating on aluminum alloy Al-6061-T6 with a 300 mJ infrared laser. The surface topography, microstructure, surface topography, surface residual stress and micro-hardness of peened and unpeened surfaces were studied. The study shows that laser peening without coating can significantly improve surface compressive stress and micro-hardness with trivial increase in surface roughness. Microstructure evaluation confirmed there was no near surface solidification after LPwC.

  9. Ballistic limit of 6061 T6 aluminum and threat to surface coatings for use with orbiting space station space suit materials

    NASA Technical Reports Server (NTRS)

    Fish, D.

    1986-01-01

    In recent years orbiting satellites, spent components, collisions and explosions have populated the near earth orbit with debris potentially more hazardous than the average meteoroid debris. This new debris has an average density of aluminum (2.78 g/cc) and an average encounter velocity of 10 km/sec. The space station will require many hours of work in this environment and there is concern over hazard to the assembly personnel. A proposed hard suit design utilizes 6061-T6 Aluminum for most of its exposed area. The aluminum surface will be treated for thermal and radiation control. The basic thickness of this suit will be on the order of 1.78 mm (0.070 inches). The selection of 6061-T6 Aluminum for space suits for use on the space station would appear to be worthwhile. The relatively ductile behavior of 6061-T6 aluminum is better than a choice of a more brittle material.

  10. Low-temperature densification of ultrafine grained aluminum 6061-T6 by polymer bonding

    NASA Astrophysics Data System (ADS)

    Kim, Boumseock

    Ultrafine grained and nanocrytalline materials have many beneficial properties such as higher hardness, strength and wear resistance. A machining process has been developed as a new method to make nanostructured metals or alloys. Through the process, severe plastic deformation can be applied to metals or alloys and they become ultrafine grain and nanocrystalline in their structures. Because ultrafine grained alloys made by machining are made up to small chips, not bulk, to make bulk material, the alloy chips must be densified through processes such as sintering. Unfortunately, during the conventional sintering, the ultrafine grained alloys show grain growth at high rate and lose their hardness and strength. Therefore, low-temperature densification of ultrafine grained alloys has been pursued. In this thesis, ultrafine-grained (UFG) Al 6061-T6 particulate produced from machining chips have been consolidated and bonded using liquid epoxies that cure at 100?, below the coarsening temperature of the UFG structure. Two routes were explored---die-pressing premixed alloy particulate and epoxy and pressure infiltration of pre-pressed alloy particulate preforms. The effects of pressing pressure and epoxy viscosity were investigated. In order to reduce porosity and contamination, three treatments---application of pressure during curing of epoxy, the cleaning of the alloy powder with NaOH solution and degassing epoxy before pressing---were tried. In order to overcome limitation of diepressing, infiltration method was compared with die-pressing and the resulting properties of the composite discussed. Bond thickness between the alloy particles increases with the viscosity of the epoxies. In the hardness results by micro-indentor, the value of composite with more than 80% volume fraction of Al alloy chip (Va) was more than 120 kg/mm2. In those measurements, the hardness of the composite depends mainly on the volume fraction of Al alloy and was clearly influenced by the boundary

  11. Effect of laser peening with different energies on fatigue fracture evolution of 6061-T6 aluminum alloy

    NASA Astrophysics Data System (ADS)

    Sheng, J.; Huang, S.; Zhou, J. Z.; Lu, J. Z.; Xu, S. Q.; Zhang, H. F.

    2016-03-01

    To deeply understand the effect of laser peening (LP) with different laser pulse energies on 6061-T6 aluminum alloy, the fatigue fracture morphologies evolution process at various fatigue crack growth (FCG) stages and the corresponding strengthen mechanism were investigated. At the initial stage of FCG, more fatigue micro-cliffs were found after LP, while the fatigue striation spacing simultaneously reduced. A "stop-continue" phenomenon of crack propagation was discovered for laser peened samples. The fatigue striation spacing at the middle stage of FCG increased significantly while compared with that at the initial stage, in addition, the fatigue striation spacing decreased with an increase in laser pulse energy. Fracture morphologies in transition region of laser peened samples exhibit a mixing fracture characteristic of striations and dimples. The laser peened sample with laser pulse energy of 7 J presents more circuitous growing paths. Due to the complex stress state induced by LP, dimples with different sizes appeared in the final fracture region.

  12. Laser shock processing to improve residual stresses with and without paint layer on 6061-T6 aluminum alloy

    NASA Astrophysics Data System (ADS)

    Gomez-Rosas, G.; Rubio-Gonzalez, C.; Ocaña, J. L.; Molpeceres, C.; Porro, J. A.; Morales, M.; Casillas, F. J.; Mora-Gonzalez, M.; Chi-Moreno, W.

    2007-03-01

    Laser shock processing (LSP) or laser shock peening has been proposed as a competitive alternative technology to classical treatments for improving fatigue and wear resistance of metals. This process induces a compressive residual stress field which increases fatigue crack initiation life and reduce fatigue crack growth rate. We present a configuration and results in the LSP concept for metal surface treatments in underwater laser irradiation at 1064 nm with and without a thin surface paint layer. A convergent lens is used to deliver 1, 2 J/cm2 with a 8 ns laser FWHM pulse produced by a 10 Hz, Q-switched Nd:YAG laser with a spot diameter of a 1,5 mm moving forward along the workpiece. A LSP configuration with experimental results using a pulse density of 5000 pulses/cm2 in 6061-T6 aluminum samples are presented.

  13. Effect of Welding Speeds on Mechanical Properties of Level Compensation Friction Stir Welded 6061-T6 Aluminum Alloy

    NASA Astrophysics Data System (ADS)

    Wen, Quan; Yue, Yumei; Ji, Shude; Li, Zhengwei; Gao, Shuangsheng

    2016-04-01

    In order to eliminate the flash, arc corrugation and concave in weld zone, level compensation friction stir welding (LCFSW) was put forward and successfully applied to weld 6061-T6 aluminum alloy with varied welding speed at a constant tool rotational speed of 1,800 rpm in the present study. The glossy joint with equal thickness of base material can be attained, and the shoulder affected zone (SAZ) was obviously reduced. The results of transverse tensile test indicate that the tensile strength and elongation reach the maximum values of 248 MPa and 7.1% when the welding speed is 600 mm/min. The microhardness of weld nugget (WN) is lower than that of base material. The tensile fracture position locates at the heat affected zone (HAZ) of the advancing side (AS), where the microhardness is the minimum. The fracture surface morphology represents the typical ductile fracture.

  14. Recovery of Mechanical Properties of a 6061-T6 Aluminum Weld by Heat Treatment After Welding

    NASA Astrophysics Data System (ADS)

    Pérez, Javier Serrano; Ambriz, Ricardo Rafael; López, Francisco Fernando Curiel; Vigueras, David Jaramillo

    2016-07-01

    The dilution effects in welds of a 6061-T6 (Al-Si-Mg) alloy obtained by the modified indirect electric arc (MIEA), using an ER4043 filler metal (Al-Si), and postweld heat treatment (PWHT) were analyzed. The soft zone (55 to 70 HV0.1) formed by the microstructural transformation in the heat-affected zone (HAZ) was eliminated. The hardness measurements were presented on a traditional microhardness profile and mapping representation. A hardening effect of the fusion zone was observed; the hardness values were above 120 HV0.1 and tended to be uniform. This behavior could be attributed to the chemical composition of the filler metal, the Mg migration from the base to the weld metal, and the reversible process of the PWHT, which promotes precipitation hardening. Improvement for yield (260 MPa) and tensile strength (310 MPa) of the MIEA joints was observed; these values were similar to those obtained for the base metal. However, the presence of porosity in the fusion zone limits the ductility of the joints (4.3 pct). Even though the yield and tensile strengths of the base metal and welded joints were similar, the stress concentration due to porosity in the weld metal generated data dispersion in fatigue life. As a consequence, the high-cycle fatigue life decreases with respect to the base metal. In contrast, when the crack propagates under elastic conditions, the crack-tip singularity is affected by the porosity in the weld metal (stress liberator). This aspect, in conjunction with the hardening effect in joints subjected to PWHT, improves the fatigue crack growth rate when compared to the as-welded condition.

  15. Recovery of Mechanical Properties of a 6061-T6 Aluminum Weld by Heat Treatment After Welding

    NASA Astrophysics Data System (ADS)

    Pérez, Javier Serrano; Ambriz, Ricardo Rafael; López, Francisco Fernando Curiel; Vigueras, David Jaramillo

    2016-05-01

    The dilution effects in welds of a 6061-T6 (Al-Si-Mg) alloy obtained by the modified indirect electric arc (MIEA), using an ER4043 filler metal (Al-Si), and postweld heat treatment (PWHT) were analyzed. The soft zone (55 to 70 HV0.1) formed by the microstructural transformation in the heat-affected zone (HAZ) was eliminated. The hardness measurements were presented on a traditional microhardness profile and mapping representation. A hardening effect of the fusion zone was observed; the hardness values were above 120 HV0.1 and tended to be uniform. This behavior could be attributed to the chemical composition of the filler metal, the Mg migration from the base to the weld metal, and the reversible process of the PWHT, which promotes precipitation hardening. Improvement for yield (260 MPa) and tensile strength (310 MPa) of the MIEA joints was observed; these values were similar to those obtained for the base metal. However, the presence of porosity in the fusion zone limits the ductility of the joints (4.3 pct). Even though the yield and tensile strengths of the base metal and welded joints were similar, the stress concentration due to porosity in the weld metal generated data dispersion in fatigue life. As a consequence, the high-cycle fatigue life decreases with respect to the base metal. In contrast, when the crack propagates under elastic conditions, the crack-tip singularity is affected by the porosity in the weld metal (stress liberator). This aspect, in conjunction with the hardening effect in joints subjected to PWHT, improves the fatigue crack growth rate when compared to the as-welded condition.

  16. On Residual Stresses in Resistance Spot-Welded Aluminum Alloy 6061-T6: Experimental and Numerical Analysis

    NASA Astrophysics Data System (ADS)

    Afshari, D.; Sedighi, M.; Karimi, M. R.; Barsoum, Z.

    2013-12-01

    In this study, an electro-thermal-structural-coupled finite element (FE) model and x-ray diffraction residual stress measurements have been utilized to analyze distribution of residual stresses in an aluminum alloy 6061-T6 resistance spot-welded joint with 2-mm-thickness sheet. Increasing the aluminum sheet thickness to more than 1 mm leads to creating difficulty in spot-welding process and increases the complexity of the FE model. The electrical and thermal contact conductances, as mandatory factors are applied in contact areas of electrode-workpiece and workpiece-workpiece to resolve the complexity of the FE model. The physical and mechanical properties of the material are defined as thermal dependent to improve the accuracy of the model. Furthermore, the electrodes are removed after the holding cycle using the birth-and-death elements method. The results have a good agreement with experimental data obtained from x-ray diffraction residual stress measurements. However, the highest internal tensile residual stress occurs in the center of the nugget zone and decreases toward nugget edge; surface residual stress increases toward the edge of the welding zone and afterward, the area decreases slightly.

  17. Full Field Measurement of The Dynamic Response of AA6061-T6 Aluminum Alloy under High Strain Rate Compression and Torsion Loads

    NASA Astrophysics Data System (ADS)

    Odoh, Daniel Oghenekewhe Oluwatobi

    The dynamic response of AA6061-T6 aluminum alloy under high strain rate loading in compression and torsion loading conditions was studied using the split Hopkinson pressure bar, the Kolsky torsion bar, and the high speed digital image correlation system. AA6061-T6 alloy, the most widely used in the AA6000 series, is a multi-purpose Al-Mg-Si-Cu alloy containing about 0.4 % wt. of Cu and other alloying additives. The properties of AA6061-T6 aluminum alloy including medium to high strength, good fracture toughness, and high corrosion resistance make it to find application in high performance structures such as the automotive parts, panels, and armored carriers. In this work, the effect of strain rate during dynamic test on formation of adiabatic shear bands in AA6061-T6 alloy was investigated. A post deformation analysis of the tested specimen was performed in order to determine the damage evolution and strain localization along the narrow adiabatic shear bands within the specimen. The formation of an adiabatic shear band in the aluminum alloy tested was found to depend on the strain rate at which the test was conducted. Stress, strain, and strain rate data obtained from the elastic waves in the compression and torsion bar tests were also compared with those obtained using the high speed digital cameras. Results show good agreement between both measurement techniques with the 3D digital image correlation technique giving a slightly lower result. Scanning and electron microscopy results show that both deformed and transformed bands can be formed in AA6061-T6 alloy during dynamic loading. The type of adiabatic shear band formed depends on the strain rate at which test was performed.

  18. Quench sensitivity of hot extruded 6061-T6 and 6069-T6 aluminum alloys

    SciTech Connect

    Bergsma, S C; Kassner, M E; Li, X; Rosen, R S

    2000-08-08

    The purpose of this study is to investigate the quench sensitivity of mechanical properties of hot extruded 6061 and 6069 aluminum alloys. The relationship between mechanical properties and quench delzty time at various temperatures between 200-500 C was determined. It was concluded that the 6069-T6 was somewhat more quench sensitive than 6061, which may be consistent with the composition difference.

  19. A Micro-Electrochemical Study of Friction Stir Welded Aluminum 6061-T6

    NASA Technical Reports Server (NTRS)

    Hintze, Paul E.; Calle, Luz M.

    2005-01-01

    The corrosion behavior of friction stir welded Aluminum alloy 606 1-T6 was studied using a micro-electrochemical cell. The micro-electrochemical cell has a measurement area of about 0.25 square mm which allows for measurement of corrosion properties at a very small scale. The corrosion and breakdown potentials were measured at many points inside and outside the weld along lines perpendicular to the weld. The breakdown potential is approximately equal inside and outside the weld; however, it is lower in the narrow border between the weld and base material. The results of electrochemical measurements were correlated to micro-structural analysis. The corrosion behavior of the friction stir welded samples was compared to tungsten inert gas (TIG) welded samples of the same material.

  20. Effects of Applied Load on 6061-T6 Aluminum Joined Employing a Novel Friction Bonding Process

    SciTech Connect

    Douglas E. Burkes; Neil P. Hallinan; Karen L. Shropshire; Peter B. Wells

    2008-12-01

    Friction bonding is under consideration for use in mass production of plate-type nuclear fuels for research reactors. This article discusses the effects of applied load (the most important process parameter for fabrication of these fuels) on temperature distribution, microstructure, and mechanical properties. Friction bonding experiments showed that tool geometry caused temperature gradients across the tool surface. Temperatures at the joint interface suggested the advancing side of the tool produced a majority of the frictional heat, while the retreating side of the tool mainly forged the plasticized material while bonding increased with applied load. The microstructure across the tool surface was also altered and, as a function of applied load, affected the mechanical properties. The 6061 aluminum alloy had mechanical properties close to a T4 temper after processing. Results documented in this article will aid in continual enhancement of friction bonding for nuclear fuel plate fabrication, and will hopefully contribute to continued advancement of friction stir welding (FSW) state of the art.

  1. Galvanic coupling between D6AC steel, 6061-T6 aluminum, Inconel 718 and graphite-epoxy composite material: Corrosion occurrence and prevention

    NASA Technical Reports Server (NTRS)

    Danford, M. D.; Higgins, R. H.

    1983-01-01

    The effects of galvanic coupling between D6AC steel, 6061-T6 aluminum, Inconel 718, and graphite-epoxy composite material (G/E) in 3.5% NaCl were studied. Measurements of corrosion potentials, galvanic currents and corrosion rates of the bare metals using weight-loss methods served to establish the need for corrosion protection in cases where D6AC steel and 6061-T6 aluminum are galvanically coupled to G/E in salt water while Inconel 718 was shown to be compatible with G/E. Six tests were made to study corrosion protective methods for eliminating galvanic corrosion in the cases of D6AC steel and 6061-T6 aluminum coupled to G/E. These results indicate that, when the G/E is completely coated with paint or a paint/polyurethane resin combination, satisfactory protection of the D6AC steel is achieved with either a coat of zinc-rich primer or a primer/topcoat combination. Likewise, satisfactory corrosion protection of the aluminum is achieved by coating it with an epoxy coating system.

  2. Barrier anodic coatings formed on 6061-T6 aluminum alloy in electrolytes containing different ethanol to water ratios

    SciTech Connect

    Panitz, J.K.G.; Sharp, D.J.; Martinez, F.E.; Merrill, R.M.; Ward, K.J.

    1988-12-01

    We have studied barrier anodic film formation on 6061-T6 aluminum alloy substrates as a function of electrolyte composition for five mixtures of ammonium tartrate dissolved in water and diluted with different amounts of ethanol. The effects of electrolyte temperatures within the range of 18/degree/C to 38/degree/C were explored. The results of this study indicate that the best dielectric coatings and the shortest processing times occur for the 100% water-ammonium tartrate electrolyte. The second best coatings and processing times occur in conjunction with the use of 98% ethanol, 2% water plus ammonium tartrate electrolyte. In general, visibly flawed coatings, scintillation events at cell voltages in excess of approximately 750-800 volts and/or abnormally long processing times occur in conjunction with the use of electrolyte mixtures containing 20%, 60%, and 90% water. We analysed samples of electrolyte as a function of usage, and evaluated the composition of the coatings using Fourier Transform Infrared Analysis to better understand the mechanisms which contribute to anodic coating growth that result in the observed variations in the dielectric properties. All of the coatings exhibited similar compositions except with regard to the amount of CO2 that was physisorbed in the coatings. The dielectrically inferior coatings that were typically produced by the electrolytes containing ethanol contain substantially more CO2 than the coatings grown in the 100% water-based electrolyte. These results strongly suggest that the ethanol in the electrolyte oxidizes and forms CO2 which is incorporated in the coatings and results in inferior dielectric properties. 8 refs., 7 figs.

  3. In-situ neutron diffraction measurements of temperature and stresses during friction stir welding of 6061-T6 aluminum alloy

    SciTech Connect

    Feng, Zhili; Wang, Xun-Li; David, Stan A; Choo, Hahn; Hubbard, Camden R; Woo, Wan Chuck; Brown, D. W.; Clausen, B; An, Ke

    2007-01-01

    The evolution of temperature and thermal stresses during friction stir welding of Al6061-T6 was investigated by means of in situ, time resolved neutron diffraction technique. A method was developed to deconvolute the temperature and stress from the lattice spacing changes measured by neutron diffraction. The deep penetration capability of neutrons made it possible for the first time to obtain the temperature and thermal stresses inside a friction stir weld.

  4. In-situ neutron diffraction measurements of temperature and stresses during friction stir welding of 6061-T6 aluminum alloy

    SciTech Connect

    Woo, Wan Chuck; Feng, Zhili; Wang, Xun-Li; Brown, D. W.; Clausen, B; An, Ke; Choo, Hahn; Hubbard, Camden R; David, Stan A

    2007-01-01

    The evolution of temperature and thermal stresses during friction stir welding of Al6061-T6 was investigated by means of in-situ, time-resolved neutron diffraction technique. A method is developed to deconvolute the temperature and stress from the lattice spacing changes measured by neutron diffraction. The deep penetration capability of neutrons made it possible for the first time to obtain the temperature and thermal stresses inside a friction stir weld.

  5. Prediction of hardness minimum locations during natural aging in an aluminum alloy 6061-T6 friction stir weld

    SciTech Connect

    Woo, Wan Chuck; Choo, Hahn; Feng, Zhili; Withers, Prof Philip

    2009-01-01

    This study describes a simple model that can predict the evolution of hardness distribution as a function of natural aging time in a heat-treatable 6061-T6 Al alloy plate subjected to friction stir welding (FSW). First, two dimensional thermal distributions were simulated as a function of time in the FSW plate by finite element modeling. Second, the hardness changes during natural aging were measured as a function of aging time for a number of Al specimens that had been previously isothermally heat-treated to different hold temperatures in order to determine the natural aging kinetics. Finally, the simulated temperature profiles and the natural aging kinetics were correlated to predict the hardness profiles in the FSW plate. The predicted hardness variations are consistent with measured hardness profiles in that the location of minimum hardness moves away from the centerline as the aging time and/or heat input increases. The hardness variation was also related to the location of failure in cross-weld tensile samples.

  6. Modeling of Residual Stresses and Property Distributions in Friction Stir Welds of Aluminum Alloy 6061-T6

    SciTech Connect

    Feng, Zhili; David, Stan A; Wang, Xun-Li; Sklad, Philip S

    2007-01-01

    An integrated thermal-metallurgical-mechanical model is used to analyze and provide insights into the formation of the residual stress and the changes in microstructure and property of Al6061-T6 friction stir welds. The simulations were conducted by means of a three-dimensional finite element model that accounts for the phenomena of frictional heating, weld microstructure and strength changes due to dissolution and reprecipitation of the hardening precipitate particles, and the mechanical workpiece/tool contact during the friction stir welding (FSW) process. The model predictions were confirmed by experimental measurement data from previous studies. For the friction stir welds investigated, it was found that the residual stress distribution is strongly dependent on the welding process parameters and the degree of material softening caused by welding. The recovery of material strength from natural aging does not increase the residual stress in the weld. The failure of friction stir weld under tensile load is controlled by the combination of the reduction in strength and the residual stresses in the heat affected zone (HAZ).

  7. Microstructure and mechanical properties of twin-wire arc sprayed Ni-Al composite coatings on 6061-T6 aluminum alloy sheet

    NASA Astrophysics Data System (ADS)

    Wang, Ji-xiao; Liu, Jing-shun; Zhang, Lun-yong; Sun, Jian-fei; Wang, Zhi-ping

    2014-05-01

    We have systematically studied the microstructure and mechanical properties of Ni-5wt%Al and Ni-20wt%Al composite coatings fabricated on 6061-T6 aluminum alloy sheet by twin-wire arc spraying under different experimental conditions. The abrasive wear behavior and interface diffusion behavior of the composite coatings were evaluated by dry/wet rubber wheel abrasive wear tests and heat treatment, respectively. Experimental results indicate that the composite coatings exhibit features of adhesive wear. Besides, the Vickers microhardness of NiAl and Ni3Al intermetallic compounds is relatively larger than that of the substrate, which is beneficial for enhancing the wear resistance. With the increase of annealing temperature and time, the interface diffusion area between the Ni-Al coating and the substrate gradually expands with the formation of NiAl3 and Ni2Al3 phases, and is controlled by diffusion of aluminum atoms. The grain growth exponent n of diffusion kinetics of the Ni-Al coating, calculated via a high-temperature diffusion model at 400, 480, and 550°C, is between 0.28 and 0.38. This satisfies the cubic law, which is consistent with the general theoretical relationship of high-temperature diffusion.

  8. The Young's modulus of 1018 steel and 6061-T6 aluminum measured from quasi-static to elastic precursor strain-rates

    NASA Astrophysics Data System (ADS)

    Rae, Philip; Trujillo, Carl; Gray, Rusty

    2009-06-01

    It is commonly assumed in engineering and physics that the elastic moduli of metals is independent of strain-rate, but is a weak function of temperature. An extensive literature search however has failed to find any citable reference in which the Young's modulus of any pedigreed metal was measured over a wide variety of strain-rates. To rectify this, samples of pedigreed 1018 steel and 6061-T6 aluminum have been tested at strain-rates from 10-4 s-1 to 10^6 s-1. Low strain-rate data (10-4-10-2 s-1)was obtained from commercial bonded strain gauges. Intermediate rate data ( 10-4 s-1) was obtained from time of flight ultrasonic measurements. Shock rate data was obtained by examining the elastic precursor using shock pins and PDV (photonic Doppler velocimetry). Correction for the adiabatic versus thermal nature of the disparate strain-rate regimes have been made. Additionally, the implications of the uniaxial strain nature of the shock elastic precursor are examined with respect to comparison with uniaxial stress lower rate data.

  9. Microscopic Observation of the Side Surface of Dynamically-Tensile-Fractured 6061-T6 and 2219-T87 Aluminum Alloys with Pre-Fatigue

    NASA Astrophysics Data System (ADS)

    Itabashi, Masaaki; Nakajima, Shigeru; Fukuda, Hiroshi

    After unexpected failure of metallic structure, microscopic investigation will be performed. Generally, such an investigation is limited to search striation pattern with a SEM (scanning electron microscope). But, when the cause of the failure was not severe repeated stress, this investigation is ineffective. In this paper, new microscopic observation technique is proposed to detect low cycle fatigue-impact tensile loading history. Al alloys, 6061-T6 and 2219-T87, were fractured in dynamic tension, after severe pre-fatigue. The side surface of the fractured specimens was observed with a SEM. Neighboring fractured surface, many opened cracks on the side surface have been generated. For each specimen, the number of the cracks was counted together with information of individual sizes and geometric features. For 6061-T6 alloy specimen with the pre-fatigue, the number of the cracks is greater than that for the specimen without the pre-fatigue. For 2219-T87 alloy, the same tendency can be found after a certain screening of the crack counting. Therefore, the crack counting technique may be useful to detect the existence of the pre-fatigue from the dynamically fractured specimen surface.

  10. In-situ Time-Resolved Neutron Diffraction Measurements of Microstructure Variations during Friction Stir Welding in a 6061-T6 Aluminum Alloy

    SciTech Connect

    Woo, Wan Chuck; Wang, Xun-Li; Ungar, Prof Tomas; Feng, Zhili; David, Stan A; Clausen, B; Hubbard, Camden R

    2008-01-01

    The microstructure change is one of the most important research areas in the friction stir welding (FSW). However, direct observation of microstructure changes during FSW has been extremely challenging because many measurement techniques are inapplicable. Recently developed in-situ time-resolved neutron diffraction methodology, which drastically improves the temporal resolution of neutron diffraction, enables to observe the transient microstructure changes during FSW. We installed a portable FSW system in the Spectrometer for MAterials Research at Temperature and Stress (SMARTS) at Los Alamos Neutron Science Center and the FSW was made on 6.35mm-thickness 6061-T6 Al alloy plate. At the same time, the neutron beam was centered on the mid-plane of the Al plate at 8 mm from the tool center (underneath the tool shoulder) and the diffraction peak was continuously measured during welding. The peak broadening analysis has been performed using the Williamson-Hall Method. The result shows that the dislocation density of about 3.2 x 10^15 m-2 duing FSW, which is the significant increse compared to the before (4.5 x 10^14 m-2) and after (4.0 x 10^14 m-2) the FSW. The quantitatively analysis of the grain structure can provide an insight to understand the transient variation of the microstructure during FSW.

  11. Evaluation of Dissimilar Welds of 5083-H12 and 6061-T6 Produced by Friction Stir Welding

    NASA Astrophysics Data System (ADS)

    Ghaffarpour, Morteza; Kolahgar, Sina; Dariani, Bijan Mollaei; Dehghani, Kamran

    2013-08-01

    In the present study, the dissimilar aluminum alloys of 5083-H12 and 6061-T6 were joined by friction stir welding (FSW). Then, the design of experiments (DOE), the Box-Benken method, and the response surface methodology (RSM) were used to optimize the effective parameters of the FSW process. The optimized parameters that led to the maximum tensile strength in dissimilar friction stir welded sheets were determined. The predicted results were then compared with those measured experimentally. The results show that there is good agreement between the predicted and measured amounts. By applying the limit dome height (LDH) test, the formability of friction stir welded sheets was studied. During the LDH test, the minimum formability occurred in the heat-affected zone (HAZ) of the 6061-T6 side. The results of microhardness and tensile tests confirm the results of the LDH tests.

  12. Evaluation of Johnson-Cook model constants for aluminum based particulate metal matrix composites

    NASA Astrophysics Data System (ADS)

    Hilfi, H.; Brar, N. S.

    1996-05-01

    High strain rate and high temperature response of three types of aluminum based particulate metal matrix ceramic composites is investigated by performing split Hopkinson pressure bar (SHPB) experiments. The composites are: NGP-2014 (15% SiC), NGT-6061 (15% SiC), and NGU-6061 (15% Al2O3), in which all the reinforcement materials are percentage by volume. Johnson-Cook constitutive model constants are evaluated from the high strain rate/high temperature data and implemented in a two dimensional finite element computer code (EPIC-2D) to simulate the penetration of an ogive nose tungsten projectile (23 grams) at a velocity 1.17 km/sec into the base 6061-T6 aluminum alloy and the composite NGU-6061. The simulated penetrations in the composite and in 6061-T6 aluminum agree with in 2%, in both materials, with the measured values.

  13. Galvanic corrosion of aluminum-matrix composites. Technical report No. 2, 1 Mar-31 Dec 90

    SciTech Connect

    Hihara, L.H.; Latanision, R.M.

    1991-02-01

    Galvanic-corrosion rates of Al-matrix composites were high in aerated chloride-containing solutions. Oxygen reduction was found to be the primary cathodic reaction. Aluminum corroded by pitting. The type of noble constituent (i.e., graphite, SiC, or TiB{sub 2}) also affected galvanic-corrosion rates. For example, results indicated that the galvanic-corrosion rate of Al should be about 30 times greater when coupled to graphite than when coupled to SiC or TiB{sub 2}. In dearated solutions, galvanic corrosion was negligible even if chlorides were present. The galvanic-corrosion rates were determined using the zero-resistance ammeter technique and from potentiodynamic polarization diagrams of ultrapure Al, 6061-T6 Al, graphite fiber, SiC, TiB2, and a commercial graphite fiber/6061-T6 Al metal-matrix composite.

  14. High strength and high ductility behavior of 6061-T6 alloy after laser shock processing

    NASA Astrophysics Data System (ADS)

    Gencalp Irizalp, Simge; Saklakoglu, Nursen

    2016-02-01

    The plastic deformation behavior of 6061-T6 alloy which was subjected to severe plastic deformation (SPD) at high strain rates during laser shock processing (LSP) was researched. In LSP-treated materials, the near surface microstructural change was examined by TEM and fracture surfaces after tensile testing were examined by SEM. An increase in strength of metallic materials brings about the decrease in ductility. In this study, the results showed that LSP-treated 6061-T6 alloy exhibited both high strength and high ductility. TEM observation showed that stacking fault (SF) ribbon enlarged, deformation twins formed and twin boundary increased in LSP-treated 6061-T6 alloy. This observation was an indication of stacking fault energy (SFE) decrease. Work hardening capability was recovered after LSP impacts.

  15. Effect of Fatigue Crack on Static Strength: 2014-T6, 2024-T4, 6061-T6, 7075-T6 Open-Hole Monobloc Specimens

    NASA Technical Reports Server (NTRS)

    Nordmark, Glenn E.; Eaton, Ian D.

    1957-01-01

    Static tensile test results are presented for specimens of 2014-T6, 2024-T4, 6061-T6, and 7075-T6 aluminum alloy containing fatigue cracks. The results are found to be in good agreement with the results reported for similar tests from other sources. The results indicate that the presence of a fatigue crack reduced the static strength, in all cases, by an amount larger than the corresponding reduction in net area; the 6061-T6 alloy specimens were least susceptible to the crack and the 7075-T6 alloy specimens were most susceptible. It is indicated that a 7075-T6 specimen may develop as little as one-third of the expected static tensile strength when the fatigue crack was consumed only one-fourth of the original area. It was found that the static strength was substantially higher for specimens which had stop holes drilled at the end of the fatigue crack.

  16. Cavitation pitting and erosion of Al 6061-T6 in mineral oil and water

    NASA Technical Reports Server (NTRS)

    Rao, B. C. S.; Buckley, D. H.

    1983-01-01

    The authors are currently carrying out a study of the cavitation erosion of different bearing metals and alloys in mineral oils were studied. The variations of weight loss, the pit diameter and depth due to cavitation erosion on Al 6061-T6 in mineral oil and water are presented.

  17. Quasi-steady state principle and in-situ real-time investigation of transient strains in 6061-T6 Al alloy using neutron diffraction

    SciTech Connect

    Woo, Wan Chuck; Brown, D. W.; Choo, Hahn; Clausen, B; David, Stan A; Feng, Zhili; Hubbard, Camden R; Wang, Xun-Li

    2007-01-01

    Neutron diffraction research has been limited to the "static" behavior of materials since the number of collected neutrons is insufficient to reach the adequate neutron counts in rapid changes of material state. In order to achieve the desired precision for the study of the transient material behavior, we propose an in-situ neutron-diffraction measurement method based on the quasi-steady state (QSS) phenomenon. The QSS principle was applied for the measurement of transient lattice spacing changes in a 6061-T6 aluminum alloy plate during thermo-mechanical processing.

  18. 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.

  19. Effects of select parameters on electron beam welding of AL6061-T6 alloy

    NASA Astrophysics Data System (ADS)

    Yost, Thomas E.

    Electron beam welding was used for joining Al6061-T6, precision machined, cylindrical sections. The welded assembly exhibited a minimum amount of distortion, but a better understanding of the effects of several key welding parameters on the structural integrity of the weld was required. The contents of this document describe the relative importance and interaction between welding speed, volume of filler, and beam pattern on the microstructural and mechanical properties of the welded joint. Understanding of the relationship between welding parameters and weld properties was accomplished by macrophotography and microstructural examination, microhardness testing, energy dispersive spectroscopy (EDX), and mechanical tensile testing of weld coupons. The results of this study will help quantify the robustness of the EBW process for this common aerospace material and joint geometry and will help determine the impacts of process deviations on weld fidelity in the production environment.

  20. Effect of Laser Shock Peening on surface properties and residual stress of Al6061-T6

    NASA Astrophysics Data System (ADS)

    Salimianrizi, A.; Foroozmehr, E.; Badrossamay, M.; Farrokhpour, H.

    2016-02-01

    The purpose of this study is to investigate the effects of Laser Shock Peening (LSP) on Al 6061-T6. The confined LSP regime using Nd: YAG laser with 1200 mJ of energy per pulse and 8 ns of pulse width were applied. The treated specimens were evaluated by means of surface integrity with optical microscopy, scanning electron microscope, microhardness, surface roughness and induced residual stress using an X-ray diffraction method. Results showed that by the use of LSP, compressive residual stress could effectively be induced on the surface of treated material. It was also revealed that the hardened depth of the material, up to a maximum depth of 1875 μm, could be achieved due to work hardening and grain refinement. In addition, surface roughness measurements showed that the LSP could deteriorate surface quality depending on the LSP parameters. The influences of beam overlap rates, number of laser shots and scanning pattern on microhardness as well as surface roughness are discussed.

  1. Structural-phase changes in Al6061-T6 alloy during high-dose N-2(+) implantation

    NASA Astrophysics Data System (ADS)

    Soukieh, M.

    2004-02-01

    N 2 + nitrogen ions with an energy of 50 keV were implanted into Al6061-T6 alloy with high dose (10(16) - 2 x 10(17) ions/cm(2)) at room temperature in order to form thin aluminium nitride (AlN) layers. The structural-phase changes in implanted Al 6061-T6 alloy were investigated using Rutherford back-scattering and transmission electron microscopic techniques. The results indicate that nitrogen implantation led to the formation of nitride phases (AlN, Al7N C-3(3)) which improved the surface hardness by 80% and increased the electrical resistance up to 1800% at maximum dose (2 x 10(17) ions/cm(2)).

  2. Parametric studies on tensile strength in joining AA6061- T6 and AA7075-T6 by gas metal arc welding process

    NASA Astrophysics Data System (ADS)

    Ishak, M.; Noordin, N. F. M.; Shah, L. H.

    2015-12-01

    Proper selection of the welding parameters can result in better joining. In this study, the effects of various welding parameters on tensile strength in joining dissimilar aluminum alloys AA6061-T6 and AA7075-T6 were investigated. 2 mm thick samples of both base metals were welded by semi-automatic gas metal arc welding (GMAW) using filler wire ER5356. The welding current, arc voltage and welding speed were chosen as variables parameters. The strength of each specimen after the welding operations were tested and the effects of these parameters on tensile strength were identified by using Taguchi method. The range of parameter for welding current were chosen from 100 to 115 A, arc voltage from 17 to 20 V and welding speed from 2 to 5 mm/s. L16 orthogonal array was used to obtained 16 runs of experiments. It was found that the highest tensile strength (194.34 MPa) was obtained with the combination of a welding current of 115 A, welding voltage of 18 V and welding speed of 4 mm/s. Through analysis of variance (ANOVA), the welding voltage was the most effected parameter on tensile strength with percentage of contribution at 41.30%.

  3. A study on ultra-precision machining technique for Al6061-T6 to fabricate space infrared optics

    NASA Astrophysics Data System (ADS)

    Ryu, Geun-man; Lee, Gil-jae; Hyun, Sang-won; Sung, Ha-yeong; Chung, Euisik; Kim, Geon-hee

    2014-08-01

    In this paper, analysis of variance on designed experiments with full factorial design was applied to determine the optimized machining parameters for ultra-precision fabrication of the secondary aspheric mirror, which is one of the key elements of the space cryogenic infrared optics. A single point diamond turning machine (SPDTM, Nanotech 4μpL Moore) was adopted to fabricate the material, AL6061-T6, and the three machining parameters of cutting speed, feed rate and depth of cut were selected. With several randomly assigned experimental conditions, surface roughness of each condition was measured by a non-contact optical profiler (NT2000; Vecco). As a result of analysis using Minitab, the optimum cutting condition was determined as following; cutting speed: 122 m/min, feed rate: 3 mm/min and depth of cut: 1 μm. Finally, a 120 mm diameter aspheric secondary mirror was attached to a particularly designed jig by using mixture of paraffin and wax and successfully fabricated under the optimum machining parameters. The profile of machined surface was measured by a high-accuracy 3-D profilometer(UA3P; Panasonic) and we obtained the geometrical errors of 30.6 nm(RMS) and 262.4 nm(PV), which satisfy the requirements of the space cryogenic infrared optics.

  4. Effects of aging treatment and heat input on the microstructures and mechanical properties of TIG-welded 6061-T6 alloy joints

    NASA Astrophysics Data System (ADS)

    Peng, Dong; Shen, Jun; Tang, Qin; Wu, Cui-ping; Zhou, Yan-bing

    2013-03-01

    Aging treatment and various heat input conditions were adopted to investigate the microstructural evolution and mechanical properties of TIG welded 6061-T6 alloy joints by microstructural observations, microhardness tests, and tensile tests. With an increase in heat input, the width of the heat-affected zone (HAZ) increases and grains in the fusion zone (FZ) coarsen. Moreover, the hardness of the HAZ decreases, whereas that of the FZ decreases initially and then increases with an increase in heat input. Low heat input results in the low ultimate tensile strength of the welded joints due to the presence of partial penetrations and pores in the welded joints. After a simple artificial aging treatment at 175°C for 8 h, the microstructure of the welded joints changes slightly. The mechanical properties of the welded joints enhance significantly after the aging process as few precipitates distribute in the welded seam.

  5. Effectiveness of metal matrix and ceramic matrix composites as orbital debris shield materials

    NASA Technical Reports Server (NTRS)

    Mcgill, Preston B.; Mount, Angela R.

    1992-01-01

    The effectiveness of two metal matrix composites and one ceramic matrix material in defeating hypervelocity impacts at about 3.8 km/s are evaluated to determine the potential of these composites as spacecraft shield materials. The metal matrix composites investigated consist of SiC particles (70 percent by volume) in an aluminum matrix and Al2O3 particles (50 percent by volume) in an Al matrix. The ceramic composite consists of ZrB2 platelets in a ZrC matrix. Both the metal matrix and ceramic matrix composites are found to perform as well or better than 6061-T6 aluminum, which is presently used in the Whipple type bumper shield of Space Station Freedom. Test results indicate that the composites tested may have applications as micrometeoroid/orbital debris shield materials.

  6. The effects of maintaining temperature in annealing heat treatment for an FSWed 6061-T6 Al alloy.

    PubMed

    Lee, Seung-Jun; Han, Min-Su; Kim, Seong-Jong

    2013-08-01

    The technological development of all kinds of lightweight transportation devices including vehicles, aircraft, ships, etc. has progressed markedly with the demand for energy saving and environmental protection. Aluminum alloy is in the spotlight as it is a suitable environmentally friendly material. However, deformation is a major problem during the welding process because aluminum alloy has a large thermal expansion coefficient. In addition, it is known that its corrosion resistance is excellent; nevertheless, in practice, considerable corrosion is generated and this is a major problem. To solve this problem, the friction stir welding (FSW) technology is applied extensively at various industrial fields as a new welding technique. This method involves a process in which materials are joined by frictional heat and physical force. Therefore, we evaluated improvements in mechanical properties and corrosion resistance through annealing heat treatment after FSW. The electrochemical experiment did not show a significant difference. However, the microstructure observation showed defectless, fine crystal particles, indicating excellent properties at 200-225°C. PMID:23920178

  7. Spark plasma sintering of aluminum matrix composites

    NASA Astrophysics Data System (ADS)

    Yadav, Vineet

    2011-12-01

    Aluminum matrix composites make a distinct category of advanced engineering materials having superior properties over conventional aluminum alloys. Aluminum matrix composites exhibit high hardness, yield strength, and excellent wear and corrosion resistance. Due to these attractive properties, aluminum matrix composites materials have many structural applications in the automotive and the aerospace industries. In this thesis, efforts are made to process high strength aluminum matrix composites which can be useful in the applications of light weight and strong materials. Spark Plasma Sintering (SPS) is a relatively novel process where powder mixture is consolidated under the simultaneous influence of uniaxial pressure and pulsed direct current. In this work, SPS was used to process aluminum matrix composites having three different reinforcements: multi-wall carbon nanotubes (MWCNTs), silicon carbide (SiC), and iron-based metallic glass (MG). In Al-CNT composites, significant improvement in micro-hardness, nano-hardness, and compressive yield strength was observed. The Al-CNT composites further exhibited improved wear resistance and lower friction coefficient due to strengthening and self-lubricating effects of CNTs. In Al-SiC and Al-MG composites, microstructure, densification, and tribological behaviors were also studied. Reinforcing MG and SiC also resulted in increase in micro-hardness and wear resistance.

  8. Tests Of Polyurethane And Dichromate Coats On Aluminum

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1992-01-01

    Report describes experiments to determine relative effectiveness of new polyurethane and more-conventional dichromate coat in helping to retard corrosion of anodized 6061-T6 aluminum. Concludes by suggesting greater protection against corrosion achieved by combining polyurethane-sealing method with hard-anodizing method and by increasing thickness of coat.

  9. Structure/property relations of aluminum under varying rates and stress states

    SciTech Connect

    Tucker, Matthew T; Horstemeyer, Mark F; Whittington, Wilburn R; Solanki, Kiran N

    2010-11-19

    In this work we analyze the plasticity, damage, and fracture characteristics of three different processed aluminum alloys (rolled 5083-H13, cast A356-T6, and extruded 6061-T6) under varying stress states (tension, compression, and torsion) and strain rates (0.001/, 1/s., and 1000/s). The stress state difference had more of a flow stress effect than the applied strain rates for those given in this study (0.001/sec up to 1000/sec). The stress state and strain rate also had a profound effect on the damage evolution of each aluminum alloy. Tension and torsional straining gave much greater damage nucleation rates than compression. Although the damage of all three alloys was found to be void nucleation dominated, the A356-T6 and 5083-H131 aluminum alloys incurred void damage via micron scale particles where the 6061-T6 aluminum alloy incurred void damage from two scales, micron-scale particles and nanoscale precipitates. Having two length scales of particles that participated in the damage evolution made the 6061-T6 incur a strain rate sensitive damage rate that was different than the other two aluminum alloys. Under tension, as the strain rate increased, the 6061-T6 aluminum alloy's void nucleation rate decreased, but the A356-T6 and 5083-H131 aluminum alloys void nucleation rate increased.

  10. Fatigue testing welded joints for P/M Al-matrix composites

    NASA Astrophysics Data System (ADS)

    Harrigan, William C.

    1994-07-01

    To meet their need for high stiffness, many bicycles currently rely on aluminum-matrix composites. The highest strength and highest stiffness form of these material, 6092/B4C/15p, is produced by powder metallurgy techniques. The bicycles are tungsten inert-gas welded and fully heat treated after welding. A test technique has been developed to assess the static and fatigue properties of welded joints. This test technique has revealed the increased stiffness and strength of a 6092/B4C/15p-T6P composite tube joint as compared with a 6061-T6 aluminum one. This test technique is currently being used to identify fatigue properties for both tube joints.

  11. Development of damped metal-matrix composites for advanced structural applications. Technical report

    SciTech Connect

    Updike, C.A.; Bhagat, R.B.

    1990-04-01

    The development of damped metal matrix composite structures for advanced applications has been investigated by the use of two different approaches: (1) the development of metal matrix composites with high intrinsic damping compared to that of the matrix material, and (2) the development of coated metal matrix composites with high structural damping compared to that of the composite substrates. The two different approaches are analyzed in terms of their potential for improved damping and feasibility for structural applications. Damping was measured by the transverse vibration of free-free beams using the bandwidth technique by a laser vibrometer under ambient conditions. The damping measurements were made over a wide range of frequencies (.7 kHz to 25.6 kHz) at low strain amplitudes (10 to the -10 power to 10 to the -7 power). Materials investigated for their tensile stiffness, strength, and damping performance include mechanically alloyed (MA) Aluminum-Magnesium, SiC(p)/Aluminum-Copper (MA), SiC(p)/AL, AL2O3(p)/AL, SiC(W)/AL, planar random Gr/AL, unidirectional Gr/AL and unidirectional SiC(Nicalon)/AL composites. The effects of coatings of high damping metals (nitinol and incramute) on 6061-T6 AL and AL2O3(p)/AL substrates have also been studied. The AL-Mg (MA), SiC(p)/AL (MA), SiC(W)/AL and th AL2O3(p)/AL composites show no significant improvement in damping compared with that of the 6061-T6 AL.

  12. The corrosion protection of several aluminum alloys by chromic acid and sulfuric acid anodizing

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1994-01-01

    The corrosion protection afforded 7075-T6, 7075-T3, 6061-T6, and 2024-T3 aluminum alloys by chromic acid and sulfuric acid anodizing was examined using electrochemical techniques. From these studies, it is concluded that sulfuric acid anodizing provides superior corrosion protection compared to chromic acid anodizing.

  13. Spin Forming of Aluminum Metal Matrix Composites

    NASA Technical Reports Server (NTRS)

    Lee, Jonathan A.; Munafo, Paul M. (Technical Monitor)

    2001-01-01

    An exploratory effort between NASA-Marshall Space Flight Center (MSFC) and SpinCraft, Inc., to experimentally spin form cylinders and concentric parts from small and thin sheets of aluminum Metal Matrix Composites (MMC), successfully yielded good microstructure data and forming parameters. MSFC and SpinCraft will collaborate on the recent technical findings and develop strategy to implement this technology for NASA's advanced propulsion and airframe applications such as pressure bulkheads, combustion liner assemblies, propellant tank domes, and nose cone assemblies.

  14. Shock-wave compression and release of aluminum/ceramic composites

    SciTech Connect

    Johnson, J.N.; Hixson, R.S.; Gray, G.T. III )

    1994-11-15

    Several composite materials consisting of ceramic particles embedded in a 6061-T6 aluminum matrix have been studied under conditions of shock-wave compression and release, including spallation. The 6061-T6 matrix represents a material for which high-rate shock-wave response has been extremely well characterized for thermoelastic-plastic deformation. The ceramic particles (alumina and mullite) are also well characterized, particularly in the elastic regime. Experimental tests consist of quasistatic, uniaxial-stress compression of both virgin and shock-recovered samples as well as time-resolved velocity interferometer measurements under conditions of flat-plate impact. The latter tests were performed with lithium fluoride windows for transmitted wave studies and free surfaces for spallation measurement. Theoretical analysis of the data is carried out with a pseudodissipation model originated by Barker [J. Composite Mat. [bold 5], 140 (1971)] for application to elastic deformation of layered composites and generalized here to include thermoelastic-plastic properties of the constituents. For a pseudodissipative model to apply to composite material response, significant geometrical randomization must be present in the composite structure; this is something that all commercially produced composites naturally possess. Randomization produces mechanical energy traps, which convert some fraction of regular, directed motion into random elastic vibrations behind the shock front. Within a few microseconds (depending on the pinned dislocation segment density) this macroscale, continuum vibrational energy is converted to heat by means of the anelastic properties of the metal matrix. The use of pseudodissipation as a means of representing dispersive composite material behavior is thus placed on a more secure physical foundation.

  15. Initial Subdivision of Genesis Early Science Polished Aluminum Collector

    NASA Technical Reports Server (NTRS)

    Allton, J. H.; Stansbery, E. K.; McNamara, K. M.; Meshik, A.; See, T. H.; Bastien, R.

    2005-01-01

    A large surface, about 245 square centimeters, of highly polished aluminum 6061 T6 alloy was attached to the science canister thermal panel for the purpose of collecting solar wind noble gases. The analysis of this collector will be part of the Genesis Early Science results. The pre-launch configuration of the collector is shown. The collector sustained some damage during the recovery impact in Utah, September 8, 2004.

  16. Aluminum-Alloy-Matrix/Alumina-Reinforcement Composites

    NASA Technical Reports Server (NTRS)

    Kashalikar, Uday; Rozenoyer, Boris

    2004-01-01

    Isotropic composites of aluminum-alloy matrices reinforced with particulate alumina have been developed as lightweight, high-specific-strength, less-expensive alternatives to nickel-base and ferrous superalloys. These composites feature a specific gravity of about 3.45 grams per cubic centimeter and specific strengths of about 200 MPa/(grams per cubic centimeter). The room-temperature tensile strength is 100 ksi (689 MPa) and stiffness is 30 Msi (206 GPa). At 500 F (260 C), these composites have shown 80 percent retention in strength and 95 percent retention in stiffness. These materials also have excellent fatigue tolerance and tribological properties. They can be fabricated in net (or nearly net) sizes and shapes to make housings, pistons, valves, and ducts in turbomachinery, and to make structural components of such diverse systems as diesel engines, automotive brake systems, and power-generation, mining, and oil-drilling equipment. Separately, incorporation of these metal matrix composites within aluminum gravity castings for localized reinforcement has been demonstrated. A composite part of this type can be fabricated in a pressure infiltration casting process. The process begins with the placement of a mold with alumina particulate preform of net or nearly net size and shape in a crucible in a vacuum furnace. A charge of the alloy is placed in the crucible with the preform. The interior of the furnace is evacuated, then the furnace heaters are turned on to heat the alloy above its liquidus temperature. Next, the interior of the furnace is filled with argon gas at a pressure about 900 psi (approximately equal to 6.2 MPa) to force the molten alloy to infiltrate the preform. Once infiltrated, the entire contents of the crucible can be allowed to cool in place, and the composite part recovered from the mold.

  17. Material damping in aluminum and metal matrix composites

    NASA Technical Reports Server (NTRS)

    Crawley, Edward F.; Van Schoor, Marthinus C.

    1987-01-01

    The material damping in beam-like specimens of aluminum and metal matrix composites was measured. A unique apparatus to determine damping by free decay while the specimens are in free fall in a vacuum was used. The specimens tested include 2024-T3 and 6061-T4 aluminum, and unidirectional graphite/metal matrix specimens with P55 and P100 fibers and 6061 Aluminum and AZ91C Magnesium as matrix materials. Tests were conducted to determine the dependence of damping on frequency and stress level. For the aluminum specimens, the material damping followed the Zener model at very low stress levels. Below the Zener relaxation frequency, a strong dependence of damping on stress was found for even moderate stress levels. Damping for the aluminum matrix materials was slightly above that predicted by the Zener model for a homogeneous bar of the matrix aluminum. For the magnesium matrix specimens, damping significantly above the Zener prediction for the homogeneous matrix material was observed.

  18. Near surface modification of aluminum alloy induced by laser shock processing

    NASA Astrophysics Data System (ADS)

    Saklakoglu, Nursen; Gencalp Irizalp, Simge; Akman, Erhan; Demir, Arif

    2014-12-01

    This paper investigates the influences of near surface modification induced in 6061-T6 aluminum alloy by laser shock processing (LSP). The present study evaluates LSP with a Q-switched Nd:YAG low power laser using water confinement medium and absorbent overlay on the workpiece. The near surface microstructural change of 6061-T6 alloy after LSP was studied. The residual stress variation throughout the depth of the workpiece was determined. The results showed an improvement of the material resistance to pit formation. This improvement may be attributed to compressive residual stress and work-hardening. The size and number of pits revealed by immersion in an NaOH-HCl solution decreased in comparison with the untreated material.

  19. Manufacturing of an aluminum alloy mold for micro-hot embossing of polymeric micro-devices

    NASA Astrophysics Data System (ADS)

    Tran, N. K.; Lam, Y. C.; Yue, C. Y.; Tan, M. J.

    2010-05-01

    In micro-hot embossing of polymeric micro-devices, e.g. microfluidic devices, the quality of the mold plays an important role in determining not only the product quality but also the overall production cost. Often the mold is made of silicon, which is brittle and fails after producing a limited number of parts. Metallic molds produced by micro-machining have a much longer life; however, the surface finish of the mold is not ideal for producing polymeric devices that require good surface finish. The metallic glass mold produced by micro-hot embossing with a silicon master is a recent development, which could produce high quality and high strength molds with long life span. However, metallic glasses are rather costly. In an attempt to reduce the production cost of the mold with acceptable quality, strength and life span, we explore here the manufacture of an aluminum alloy (AA6061-T6) mold by hot embossing using a silicon master. Using a set of channels to be produced on the aluminum alloy as the benchmark, we examine the orientation effect of the channels on the AA6061-T6 mold produced by hot embossing. Finally, to examine the effectiveness of the AA6061-T6 mold, it is employed for the hot embossing of polymeric (TOPAS 8007) substrates.

  20. Fracture of boron filaments in an aluminum matrix.

    NASA Technical Reports Server (NTRS)

    Steele, J. H.; Herring, H. W.

    1972-01-01

    The B-Al composite specimens tested in this study were fabricated by diffusion bonding of 1230 aluminum foil and boron filaments placed in alternate layers, using an acrylic resin solution to maintain filament spacing. The specimens were put under tensile stresses parallel to the filaments, and filament fracture was monitored acoustically under loads. Fracture of specimens under loads was caused by break propagation with a characteristic wedge-type fragmentation pattern indicating its direction. The aluminum foil matrix of the specimens failed by ductile shear type fracture after the break of the filaments.

  1. Aluminum alloy welding and stress-corrosion testing. Final report

    SciTech Connect

    Gates, W.G.; Jimenez, E.

    1981-04-01

    The weldability, strength, and corrosion resistance of four 5XXX aluminum alloys electron beam welded to 6061-T6 aluminum alloy without a filler metal were evaluated. Adding filler metal raises weld energy requirements and makes the process more difficult to control. In this study, instead of using a filler metal, a high-magnesium 5XXX alloy was welded to the 6061 alloy. The four 5XXX alloys used (5456-H321, 5052-H34, 5086-H323, and 5083-H32) were selected for their high magnesium content which reduces weld crack sensitivity.

  2. Ductility of a continuous fiber reinforced aluminum matrix composite

    NASA Technical Reports Server (NTRS)

    Jansson, S.; Leckie, Frederick A.

    1991-01-01

    The transverse properties of an aluminum alloy metal matrix composite reinforced by continuous alumina fibers have been investigated. The composite is subjected to both mechanical and cyclic thermal loading. The ductility can vary by an order of magnitude according to the operating conditions. For high mechanical and low thermal loading the ductility is small, for low mechanical and high thermal loading the ductility is an order of magnitude higher. Experiments on a beam in bending confirm that the ductility is strongly dependent on the loading conditions. The observations suggest a means of utilizing the inherent ductility of the matrix.

  3. Fracture toughness of SiC/Al metal matrix composite

    NASA Technical Reports Server (NTRS)

    Flom, Yury; Parker, B. H.; Chu, H. P.

    1989-01-01

    An experimental study was conducted to evaluate fracture toughness of SiC/Al metal matrix composite (MMC). The material was a 12.7 mm thick extrusion of 6061-T6 aluminum alloy with 40 v/o SiC particulates. Specimen configuration and test procedure conformed to ASTM E399 Standard for compact specimens. It was found that special procedures were necessary to obtain fatigue cracks of controlled lengths in the preparation of precracked specimens for the MMC material. Fatigue loading with both minimum and maximum loads in compression was used to start the precrack. The initial precracking would stop by self-arrest. Afterwards, the precrack could be safely extended to the desired length by additional cyclic tensile loading. Test results met practically all the E399 criteria for the calculation of plane strain fracture toughness of the material. A valid K sub IC value of the SiC/Al composite was established as K sub IC = 8.9 MPa square root of m. The threshold stress intensity under which crack would cease to grow in the material was estimated as delta K sub th = 2MPa square root of m for R = 0.09 using the fatigue precracking data. Fractographic examinations show that failure occurred by the micromechanism involved with plastic deformation although the specimens broke by brittle fracture. The effect of precracking by cyclic loading in compression on fracture toughness is included in the discussion.

  4. Dual-nanoparticulate-reinforced aluminum matrix composite materials

    NASA Astrophysics Data System (ADS)

    Kwon, Hansang; Cho, Seungchan; Leparoux, Marc; Kawasaki, Akira

    2012-06-01

    Aluminum (Al) matrix composite materials reinforced with carbon nanotubes (CNT) and silicon carbide nanoparticles (nano-SiC) were fabricated by mechanical ball milling, followed by hot-pressing. Nano-SiC was used as an active mixing agent for dispersing the CNTs in the Al powder. The hardness of the produced composites was dramatically increased, up to eight times higher than bulk pure Al, by increasing the amount of nano-SiC particles. A small quantity of aluminum carbide (Al4C3) was observed by TEM analysis and quantified using x-ray diffraction. The composite with the highest hardness values contained some nanosized Al4C3. Along with the CNT and the nano-SiC, Al4C3 also seemed to play a role in the enhanced hardness of the composites. The high energy milling process seems to lead to a homogeneous dispersion of the high aspect ratio CNTs, and of the nearly spherical nano-SiC particles in the Al matrix. This powder metallurgical approach could also be applied to other nanoreinforced composites, such as ceramics or complex matrix materials.

  5. Dual-nanoparticulate-reinforced aluminum matrix composite materials.

    PubMed

    Kwon, Hansang; Cho, Seungchan; Leparoux, Marc; Kawasaki, Akira

    2012-06-01

    Aluminum (Al) matrix composite materials reinforced with carbon nanotubes (CNT) and silicon carbide nanoparticles (nano-SiC) were fabricated by mechanical ball milling, followed by hot-pressing. Nano-SiC was used as an active mixing agent for dispersing the CNTs in the Al powder. The hardness of the produced composites was dramatically increased, up to eight times higher than bulk pure Al, by increasing the amount of nano-SiC particles. A small quantity of aluminum carbide (Al(4)C(3)) was observed by TEM analysis and quantified using x-ray diffraction. The composite with the highest hardness values contained some nanosized Al(4)C(3). Along with the CNT and the nano-SiC, Al(4)C(3) also seemed to play a role in the enhanced hardness of the composites. The high energy milling process seems to lead to a homogeneous dispersion of the high aspect ratio CNTs, and of the nearly spherical nano-SiC particles in the Al matrix. This powder metallurgical approach could also be applied to other nanoreinforced composites, such as ceramics or complex matrix materials. PMID:22571898

  6. Development of a Precipitation-Strengthened Matrix for Non-quenchable Aluminum Metal Matrix Composites

    NASA Astrophysics Data System (ADS)

    Vo, Nhon Q.; Sorensen, Jim; Klier, Eric M.; Sanaty-Zadeh, Amirreza; Bayansan, Davaadorj; Seidman, David N.; Dunand, David C.

    2016-04-01

    Recent developments in metal matrix composite-encapsulated ceramic armor show promise in lightweight armor technology. The system contains ceramic tiles, such as alumina, sandwiched between unreinforced aluminum or aluminum metal matrix composite (Al-MMC), which has a better toughness compared to the ceramic tiles. The sandwich structures should not be quenched during the fabrication, as the large mismatch in the coefficients of thermal expansion between the ceramic tiles and the unreinforced aluminum or Al-MMC creates internal stresses high enough to fracture the ceramic tiles. However, slow cooling of most commercial alloys creates large precipitates making solute unavailable for the formation of fine precipitates during aging. Here, we develop a non-quenched, high-strength metal matrix utilizing dilute Al-Sc-Zr alloys. We demonstrate that the dilute Al-0.09 Sc-0.045 Zr at.% alloy and the same alloy containing 0-4 vol.% alumina short fibers do not result in precipitation upon slow cooling from a high temperature, and can thereafter be aged to increase their strength. They exhibit a moderate strength, but improved ductility and toughness as compared to common armor aluminum alloys, such as AA5083-H131, making them attractive as armor materials and hybrid armor systems.

  7. Development of a Precipitation-Strengthened Matrix for Non-quenchable Aluminum Metal Matrix Composites

    NASA Astrophysics Data System (ADS)

    Vo, Nhon Q.; Sorensen, Jim; Klier, Eric M.; Sanaty-Zadeh, Amirreza; Bayansan, Davaadorj; Seidman, David N.; Dunand, David C.

    2016-07-01

    Recent developments in metal matrix composite-encapsulated ceramic armor show promise in lightweight armor technology. The system contains ceramic tiles, such as alumina, sandwiched between unreinforced aluminum or aluminum metal matrix composite (Al-MMC), which has a better toughness compared to the ceramic tiles. The sandwich structures should not be quenched during the fabrication, as the large mismatch in the coefficients of thermal expansion between the ceramic tiles and the unreinforced aluminum or Al-MMC creates internal stresses high enough to fracture the ceramic tiles. However, slow cooling of most commercial alloys creates large precipitates making solute unavailable for the formation of fine precipitates during aging. Here, we develop a non-quenched, high-strength metal matrix utilizing dilute Al-Sc-Zr alloys. We demonstrate that the dilute Al-0.09 Sc-0.045 Zr at.% alloy and the same alloy containing 0-4 vol.% alumina short fibers do not result in precipitation upon slow cooling from a high temperature, and can thereafter be aged to increase their strength. They exhibit a moderate strength, but improved ductility and toughness as compared to common armor aluminum alloys, such as AA5083-H131, making them attractive as armor materials and hybrid armor systems.

  8. Numerical analysis on thermal drilling of aluminum metal matrix composite

    NASA Astrophysics Data System (ADS)

    Hynes, N. Rajesh Jesudoss; Maheshwaran, M. V.

    2016-05-01

    The work-material deformation is very large and both the tool and workpiece temperatures are high in thermal drilling. Modeling is a necessary tool to understand the material flow, temperatures, stress, and strains, which are difficult to measure experimentally during thermal drilling. The numerical analysis of thermal drilling process of aluminum metal matrix composite has been done in the present work. In this analysis the heat flux of different stages is calculated. The calculated heat flux is applied on the surface of work piece and thermal distribution is predicted in different stages during the thermal drilling process.

  9. Ultrasonic Assessment of Impact-Induced Damage and Microcracking in Polymer Matrix Composites

    NASA Technical Reports Server (NTRS)

    Liaw, Benjamin; Villars, Esther; Delmont, Frantz; Bowles, Kenneth J. (Technical Monitor)

    2001-01-01

    The main objective of this NASA FAR project is to conduct ultrasonic assessment of impact-induced damage and microcracking in polymer matrix composites at various temperatures. It is believed that the proposed study of impact damage assessment on polymer matrix composites will benefit several NASA missions and current interests, such as ballistic impact testing of composite fan containment and high strain rate deformation modeling of polymer matrix composites. Impact-induced damage mechanisms in GLARE and ARALL fiber-metal laminates subject to instrumented drop-weight impacts at various temperatures were studied. GLARE and ARALL are hybrid composites made of alternating layers of aluminum and glass (for GLARE) and aramid- (for ARALL) fiber-reinforced epoxy. Damage in pure aluminum panels impacted by foreign objects was mainly characterized by large plastic deformation surrounding a deep penetration dent. On the other hand, plastic deformation in fiber-metal laminates was often not as severe although the penetration dent was still produced. The more stiff fiber-reinforced epoxy layers provided better bending rigidity; thus, enhancing impact damage tolerance. Severe cracking, however, occurred due to the use of these more brittle fiber-reinforced epoxy layers. Fracture patterns, e.g., crack length and delamination size, were greatly affected by the lay-up configuration rather than by the number of layers, which implies that thickness effect was not significant for the panels tested in this study. Immersion ultrasound techniques were then used to assess damages generated by instrumented drop-weight impacts onto these fiber-metal laminate panels as well as 6061-T6 aluminum/cast acrylic sandwich plates adhered by epoxy. Depending on several parameters, such as impact velocity, mass, temperature, laminate configuration, sandwich construction, etc., various types of impact damage were observed, including plastic deformation, radiating cracks emanating from the impact site

  10. Characterization of tribological behaviour of graphitic aluminum matrix composites, grey cast iron, and aluminum silicon alloys

    NASA Astrophysics Data System (ADS)

    Riahi, Ahmad Reza

    In recent years a number of aluminum-silicon alloys and some graphitic aluminum matrix composites have been fabricated for potential tribological applications in the automotive industry, in particular for lightweight high efficiency internal combustion engines to replace conventional uses of cast iron. This study provides a systematic investigation for wear mechanisms in dry sliding of the graphitic aluminum-matrix composites (A356 Al-10%SiC-4%Gr and A356 Al-5%Al2O3-3%Gr) developed for cylinder liner applications. Two eutectic Al-Si alloys (modified with rare earth elements) developed for wear resistant engine blocks were also studied. The tribological behavior of grey cast iron (ASTM A30), which is a traditional material for engine components, was also investigated as reference. For graphitic aluminum matrix composites, a wear mapping approach has been adopted. Three main regimes: ultra mild, mild and severe wear regions were determined in the maps; additionally, a scuffing region was observed. In the ultra mild wear regime the wear resistance was primarily due to the hard particles supporting the load. It was shown that the onset of severe wear in graphitic composites occurred at considerably higher loads compared to A356 aluminum alloy and A356 Al-20% SiC composite. At the onset of severe wear, the surface temperatures and coefficient of friction of the graphitic composites was lower than that of A356 Al-20% SiC. At all testing conditions in the mild wear regime, a protective tribo-layer was formed, which by increasing the speed and load became more continuous, more compact, smoother, and harder. The tribo-layers were removed at the onset of severe wear. An experimental wear map of grey cast iron was constructed; it consisted of three wear regimes: ultra mild, mild and severe wear. In the ultra mild regime a compacted fine iron oxide powder formed on the contact. The onset of severe wear was started with local material transfer to the steel counterface, and

  11. Ultrasonic Assessment of Impact-Induced Damage and Microcracking in Polymer Matrix Composites

    NASA Technical Reports Server (NTRS)

    Liaw, Benjamin; Zeichner, Glenn; Liu, Yanxiong; Bowles, Kenneth J. (Technical Monitor)

    2000-01-01

    The main objective of this NASA FAR project is to conduct ultrasonic assessment of impact-induced damage and microcracking in polymer matrix composites at various temperatures. It is believed that the proposed study of impact damage assessment on polymer matrix composites will benefit several NASA's missions and current interests, such as ballistic impact testing of composite fan containment and high strain rate deformation modeling of polymer matrix composites. Currently, impact-induced delamination and fracture in 6061-T6 aluminum/cast acrylic sandwich plates adhered by epoxy were generated in an instrumented drop-weight impact machine. Although only a small dent was produced on the aluminum side when a hemispherical penetrator tup was dropped onto it from a couple of inches, a large ring of delamination at the interface was observed. The delamination damage was often accompanied by severe shattering in the acrylic substratum. Damage patterns in the acrylic layer include radial and ring cracks and, together with delamination at the interface, may cause peeling-off of acrylic material from the sandwich plate. Theory of stress-wave propagation can be used to explain these damage patterns. The impact tests were conducted at various temperatures. The results also show clearly that temperature effect is very important in impact damage. For pure cast acrylic nil-ductile transition (NDT) occurs between 185-195 F Excessive impact energy was dissipated into fracture energy when tested at temperature below this range or through plastic deformation when tested at temperature above the NDT temperature. Results from this study will be used as baseline data for studying fiber-metal laminates, such as GLARE and ARALL for advanced aeronautical and astronautical applications.

  12. Hot extruded carbon nanotube reinforced aluminum matrix composite materials

    NASA Astrophysics Data System (ADS)

    Kwon, Hansang; Leparoux, Marc

    2012-10-01

    Carbon nanotube (CNT) reinforced aluminum (Al) matrix composite materials were successfully fabricated by mechanical ball milling followed by powder hot extrusion processes. Microstructural analysis revealed that the CNTs were well dispersed at the boundaries and were aligned with the extrusion direction in the composites obtained. Although only a small quantity of CNTs were added to the composite (1 vol%), the Vickers hardness and the tensile strength were significantly enhanced, with an up to three-fold increase relative to that of pure Al. From the fractography of the extruded Al-CNT composite, several shapes were observed in the fracture surface, and this unique morphology is discussed based on the strengthening mechanism. The damage in the CNTs was investigated with Raman spectroscopy. However, the Al-CNT composite materials were not only strengthened by the addition of CNTs but also enhanced by several synergistic effects. The nanoindentation stress-strain curve was successfully constructed by setting the effective zero-load and zero-displacement points and was compared with the tensile stress-strain curve. The yield strengths of the Al-CNT composites from the nanoindentation and tensile tests were compared and discussed. We believe that the yield strength can be predicted using a simple nanoindentation stress/strain curve and that this method will be useful for materials that are difficult to machine, such as complex ceramics.

  13. Hot extruded carbon nanotube reinforced aluminum matrix composite materials.

    PubMed

    Kwon, Hansang; Leparoux, Marc

    2012-10-19

    Carbon nanotube (CNT) reinforced aluminum (Al) matrix composite materials were successfully fabricated by mechanical ball milling followed by powder hot extrusion processes. Microstructural analysis revealed that the CNTs were well dispersed at the boundaries and were aligned with the extrusion direction in the composites obtained. Although only a small quantity of CNTs were added to the composite (1 vol%), the Vickers hardness and the tensile strength were significantly enhanced, with an up to three-fold increase relative to that of pure Al. From the fractography of the extruded Al-CNT composite, several shapes were observed in the fracture surface, and this unique morphology is discussed based on the strengthening mechanism. The damage in the CNTs was investigated with Raman spectroscopy. However, the Al-CNT composite materials were not only strengthened by the addition of CNTs but also enhanced by several synergistic effects. The nanoindentation stress-strain curve was successfully constructed by setting the effective zero-load and zero-displacement points and was compared with the tensile stress-strain curve. The yield strengths of the Al-CNT composites from the nanoindentation and tensile tests were compared and discussed. We believe that the yield strength can be predicted using a simple nanoindentation stress/strain curve and that this method will be useful for materials that are difficult to machine, such as complex ceramics. PMID:23011263

  14. Microstructural Characterization of Friction Stir Welded Aluminum-Steel Joints

    NASA Astrophysics Data System (ADS)

    Patterson, Erin E.; Hovanski, Yuri; Field, David P.

    2016-06-01

    This work focuses on the microstructural characterization of aluminum to steel friction stir welded joints. Lap weld configuration coupled with scribe technology used for the weld tool have produced joints of adequate quality, despite the significant differences in hardness and melting temperatures of the alloys. Common to friction stir processes, especially those of dissimilar alloys, are microstructural gradients including grain size, crystallographic texture, and precipitation of intermetallic compounds. Because of the significant influence that intermetallic compound formation has on mechanical and ballistic behavior, the characterization of the specific intermetallic phases and the degree to which they are formed in the weld microstructure is critical to predicting weld performance. This study used electron backscatter diffraction, energy dispersive spectroscopy, scanning electron microscopy, and Vickers micro-hardness indentation to explore and characterize the microstructures of lap friction stir welds between an applique 6061-T6 aluminum armor plate alloy and a RHA homogeneous armor plate steel alloy. Macroscopic defects such as micro-cracks were observed in the cross-sectional samples, and binary intermetallic compound layers were found to exist at the aluminum-steel interfaces of the steel particles stirred into the aluminum weld matrix and across the interfaces of the weld joints. Energy dispersive spectroscopy chemical analysis identified the intermetallic layer as monoclinic Al3Fe. Dramatic decreases in grain size in the thermo-mechanically affected zones and weld zones that evidenced grain refinement through plastic deformation and recrystallization. Crystallographic grain orientation and texture were examined using electron backscatter diffraction. Striated regions in the orientations of the aluminum alloy were determined to be the result of the severe deformation induced by the complex weld tool geometry. Many of the textures observed in the weld

  15. Microstructural Characterization of Friction Stir Welded Aluminum-Steel Joints

    NASA Astrophysics Data System (ADS)

    Patterson, Erin E.; Hovanski, Yuri; Field, David P.

    2016-03-01

    This work focuses on the microstructural characterization of aluminum to steel friction stir welded joints. Lap weld configuration coupled with scribe technology used for the weld tool have produced joints of adequate quality, despite the significant differences in hardness and melting temperatures of the alloys. Common to friction stir processes, especially those of dissimilar alloys, are microstructural gradients including grain size, crystallographic texture, and precipitation of intermetallic compounds. Because of the significant influence that intermetallic compound formation has on mechanical and ballistic behavior, the characterization of the specific intermetallic phases and the degree to which they are formed in the weld microstructure is critical to predicting weld performance. This study used electron backscatter diffraction, energy dispersive spectroscopy, scanning electron microscopy, and Vickers micro-hardness indentation to explore and characterize the microstructures of lap friction stir welds between an applique 6061-T6 aluminum armor plate alloy and a RHA homogeneous armor plate steel alloy. Macroscopic defects such as micro-cracks were observed in the cross-sectional samples, and binary intermetallic compound layers were found to exist at the aluminum-steel interfaces of the steel particles stirred into the aluminum weld matrix and across the interfaces of the weld joints. Energy dispersive spectroscopy chemical analysis identified the intermetallic layer as monoclinic Al3Fe. Dramatic decreases in grain size in the thermo-mechanically affected zones and weld zones that evidenced grain refinement through plastic deformation and recrystallization. Crystallographic grain orientation and texture were examined using electron backscatter diffraction. Striated regions in the orientations of the aluminum alloy were determined to be the result of the severe deformation induced by the complex weld tool geometry. Many of the textures observed in the weld

  16. Degradation Mechanisms in Aluminum Matrix Composites: Alumina/Aluminum and Boron/Aluminum. Ph.D. Thesis - North Carolina State Univ. at Raleigh

    NASA Technical Reports Server (NTRS)

    Olsen, G. C.

    1981-01-01

    The effects of fabrication and long term thermal exposure (up to 10,000 hours at 590 K) on two types of aluminum matrix composites were examined. An alumina/aluminum composite, was made of continuous alpha Al2O3 fibers in a matrix of commercially pure aluminum alloyed with 2.8% lithium. The mechanical properties of the material, the effect of isothermal exposure, cyclic thermal exposure, and fatigue are presented. Two degradation mechanisms are identified. One was caused by formation of a nonstoichiometric alumina during fabrication, the other by a loss of lithium to a surface reaction during long term thermal exposure. The other composite, boron/aluminum, made of boron fibers in an aluminum matrix, was investigated using five different aluminum alloys for the matrices. The mechanical properties of each material and the effect of isothermal and cyclic thermal exposure are presented. The effects of each alloy constituent on the degradation mechanisms are discussed. The effects of several reactions between alloy constituents and boron fibers on the composite properties are discussed.

  17. Alkaline oxide conversion coatings for aluminum alloys

    SciTech Connect

    Buchheit, R.G.

    1996-02-01

    Three related conversion coating methods are described that are based on film formation which occurs when aluminum alloys are exposed to alkaline Li salt solutions. Representative examples of the processing methods, resulting coating structure, composition and morphology are presented. The corrosion resistance of these coatings to aerated 0.5 M NaCl solution has been evaluated as a function of total processing time using electrochemical impedance spectroscopy (EIS). This evaluation shows that excellent corrosion resistance can be uniformly achieved using no more than 20 minutes of process time for 6061-T6. Using current methods a minimum of 80 minutes of process time is required to get marginally acceptable corrosion resistance for 2024-T3. Longer processing times are required to achieve uniformly good corrosion resistance.

  18. The mechanical properties measurement of multiwall carbon nanotube reinforced nanocrystalline aluminum matrix composite

    NASA Astrophysics Data System (ADS)

    Sharma, Manjula; Pal, Hemant; Sharma, Vimal

    2015-05-01

    Nanocrystalline aluminum matrix composite containing carbon nanotubes were fabricated using physical mixing method followed by cold pressing. The microstructure of the composite has been investigated using X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy techniques. These studies revealed that the carbon nanotubes were homogeneously dispersed throughout the metal matrix. The consolidated samples were pressureless sintered in inert atmosphere to further actuate a strong interface between carbon nanotubes and aluminum matrix. The nanoindentation tests carried out on considered samples showed that with the addition of 0.5 wt% carbon nanotubes, the hardness and elastic modulus of the aluminum matrix increased by 21.2 % and 2 % repectively. The scratch tests revealed a decrease in the friction coefficient of the carbon nanotubes reinforced composite due to the presence of lubricating interfacial layer. The prepared composites were promising entities to be used in the field of sporting goods, construction materials and automobile industries.

  19. The mechanical properties measurement of multiwall carbon nanotube reinforced nanocrystalline aluminum matrix composite

    SciTech Connect

    Sharma, Manjula Pal, Hemant; Sharma, Vimal

    2015-05-15

    Nanocrystalline aluminum matrix composite containing carbon nanotubes were fabricated using physical mixing method followed by cold pressing. The microstructure of the composite has been investigated using X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy techniques. These studies revealed that the carbon nanotubes were homogeneously dispersed throughout the metal matrix. The consolidated samples were pressureless sintered in inert atmosphere to further actuate a strong interface between carbon nanotubes and aluminum matrix. The nanoindentation tests carried out on considered samples showed that with the addition of 0.5 wt% carbon nanotubes, the hardness and elastic modulus of the aluminum matrix increased by 21.2 % and 2 % repectively. The scratch tests revealed a decrease in the friction coefficient of the carbon nanotubes reinforced composite due to the presence of lubricating interfacial layer. The prepared composites were promising entities to be used in the field of sporting goods, construction materials and automobile industries.

  20. Low-cost, fly-ash-containing aluminum-matrix composites

    NASA Astrophysics Data System (ADS)

    Rohatgi, Pradeep K.

    1994-11-01

    In recent years there has been considerable activity in the development of metal-matrix composites, especially for aerospace, ground transportation, and the leisure industry. Short-fiber-reinforced pistons and cylinder blocks have been marketed by Japanese companies for several years. It is likely that in the near future cast particulate composites like aluminum-graphite, aluminum-silicon carbide, and aluminum-alumina will find widespread applications as brake rotors, drive shafts, cylinder liners, connecting rods, and wrist pins. The cost of metal-matrix composites has been one of the major barriers toward their widespread application. This paper describes the development of cast aluminum-fly ash particle composites (ash alloy). Incorporation of fly-ash particles, which are a waste by-product of coal-based power generation, reduces the cost of aluminum castings by acting as a filler; decreases their density, and increases their hardness, abrasion resistance, and stiffness. Several prototype castings have been made from aluminum-fly ash composites to demonstrate their castability. With sustained research and the support of manufacturing organizations, these alloys can find widespread applications as low-cost aluminum composite components.

  1. Pressureless infiltration of aluminum metal-matrix composites

    SciTech Connect

    Kajikawa, Y.; Nukami, T.; Flemings, M.C.

    1995-08-01

    Pressureless infiltration of ceramic preforms by molten aluminum is described. The preforms are SiC with varying amounts of particulate Al, Ti, and Ni. Infiltrants employed are pure Al and Al-12.5 wt pct Si. It is shown that a pressure differential within the preform is required for infiltration, and measurements are made of pressure changes in the preforms during infiltration. Results indicate that atmospheric pressure is essential for infiltration but that capillarity may play a role as well.

  2. High-Temperature Fatigue of a Hybrid Aluminum Metal Matrix Composite

    NASA Astrophysics Data System (ADS)

    Clark, J. T.; Sanders, P. G.

    2014-01-01

    An aluminum metal matrix composite (MMC) brake drum was tested in fatigue at room temperature and extreme service temperatures. At room temperature, the hybrid composite did not fail and exceeded estimated vehicle service times. At higher temperatures (62 and 73 pct of the matrix eutectic), fatigue of a hybrid particle/fiber MMC exhibited failure consistent with matrix overloading. Overaging of the A356 matrix coupled with progressive fracture of the SiC particles combined to create the matrix overload condition. No evidence of macro-fatigue crack initiation or growth was observed, and the matrix-particle interface appeared strong with no debonding, visible matrix phases, or porosity. An effective medium model was constructed to test the hypothesis that matrix overloading was the probable failure mode. The measured particle fracture rate was fit using realistic values of the SiC Weibull strength and modulus, which in turn predicted cycles to failure within the range observed in fatigue testing.

  3. Aluminum-matrix electrotechnical composite alloys hardened by endogenous nano- and microphases

    NASA Astrophysics Data System (ADS)

    Babkin, V. G.; Terent'ev, N. A.; Cherepanov, A. I.

    2014-09-01

    A method is developed to manufacture aluminum-matrix composite alloys hardened by endogenous nano- and microphases. The formation of the structure and properties of the composite materials is studied. The experimental results demonstrate that the developed alloys are promising to produce electro-technical wire rods and other electrotechnical products.

  4. Growth of silicon particles in an aluminum matrix

    NASA Astrophysics Data System (ADS)

    Rhines, F. N.; Aballe, M.

    1986-12-01

    The growth of silicon particles in cast aluminum-silicon alloys, during isothermal heat treatment, has been studied three-dimensionally with the aid of the global parameters of quantitative microscopy and with the Coulter Counter. The measured particle volume distribution can be represented as being log-normal, its geometric standard deviation of the distribution maintaining a constant value throughout isothermal growth. Increase in the average particle volume is in direct proportion to time. Its rate is an Arrhenius function of temperature, with an activation energy of about 80 kilo-calories per mol. The growth rate is the same in all alloys from 4 to 12 pct of silicon, showing that it is independent of particle spacing and, therefore, not controlled by long-range diffusion. This is indicated also by the high activation energy. In its mechanism, the growth of silicon particles is analogous, in broad outline, to steady state grain growth in a polycrystalline aggregate. Interfacial tension provides the energy, which is expended in decrease of surface area as growth proceeds. The rate depends jointly upon the mobility of the interface and upon a microstructural rate constant. The latter is related to the geometric standard deviation of the volume distribution and may be expressed in terms of the global parameter ratio M vSv/Nv. The growth process has been analyzed as a system.

  5. Fabrication of multi-walled carbon nanotubes-aluminum matrix composite by powder metallurgy technique

    NASA Astrophysics Data System (ADS)

    Bunakov, N. A.; Kozlov, D. V.; Golovanov, V. N.; Klimov, E. S.; Grebchuk, E. E.; Efimov, M. S.; Kostishko, B. B.

    We report on fabrication of an aluminum matrix composite containing multi-walled carbon nanotubes (MWCNTs) produced by MOCVD method and functionalized via acid treatment by a H2SO4/HNO3 mixture. Specimens were prepared by spark plasma sintering (SPS) of the aluminum powder with different amounts of functionalized MWCNTs (FMWCNTs) in the range of 0.1-1 wt.%. We studied the effect of FMWCNTs amount on microstructure and mechanical properties of composites. It is shown that functionalization allows homogeneous dispersing of the MWCNTs in Al powder. The maximal increase in micro-hardness and tensile strength is registered at 0.1 wt.%.

  6. Pathways to a family of low-cost, high-performance, metal matrix composites based on aluminum diboride in aluminum

    NASA Astrophysics Data System (ADS)

    Hall, Aaron Christopher

    The continued development of a new family of metal matrix composites based on the in-situ formation of AlB2 flakes in liquid aluminum is described. First, a new synthesis technique for the preparation of high aspect ratio AlB2 is demonstrated. Borax and B2O 3 were reacted with molten aluminum to prepare high aspect ratio AlB 2. The focus then shifts to further understanding the Al-B alloy system. Work on the Al-B alloy system concentrated on the Al(L) + AlB 2 → Al(L) + AlB12 peritectic transformation and the growth of AlB2 in aluminum. The equilibrium peritectic transformation temperature was redetermined and found to be 950 +/- 5°C. The kinetics of the peritectic transformation were measured and reported for the first time. Cu, Fe, and Si additions were made to the alloy, and their effect on the peritectic reaction was investigated. All three elements shorten the time required for the peritectic reaction to occur. The effect of these three elements on flake growth was also investigated. They each caused a reduction in the size of growing AlB2 flakes. Finally two samples containing more than 30v% AlB2 in aluminum were prepared. Their properties were measured. The sample containing 40v% AlB2 exhibited a flexural strength of 200 MPa. The 35v% sample exhibited a flexural strength of 150 MPa. When the 35v% sample was tested in compression, it exhibited an ultimate strength close to 200 MPa. Its modulus varied from 200--300 GPa depending on the orientation of the loading axis with respect to the flake reinforcement.

  7. Fabrication of carbon nanofiber-reinforced aluminum matrix composites assisted by aluminum coating formed on nanofiber surface by in situ chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Ogawa, Fumio; Masuda, Chitoshi

    2015-01-01

    The van der Waals agglomeration of carbon nanofibers (CNFs) and the weight difference and poor wettability between CNFs and aluminum hinder the fabrication of dense CNF-reinforced aluminum matrix composites with superior properties. In this study, to improve this situation, CNFs were coated with aluminum by a simple and low-cost in situ chemical vapor deposition (in situ CVD). Iodine was used to accelerate the transport of aluminum atoms. The coating layer formed by the in situ CVD was characterized using scanning electron microscopy, transmission electron microscopy, x-ray diffraction, Fourier transform-infrared spectroscopy, and x-ray photoelectron spectroscopy. The results confirmed that the CNFs were successfully coated with aluminum. The composites were fabricated to investigate the effect of the aluminum coating formed on the CNFs. The dispersion of CNFs, density, Vickers micro-hardness and thermal conductivity of the composites fabricated by powder metallurgy were improved. Pressure-less infiltration experiments were conducted to fabricate composites by casting. The results demonstrated that the wettability and infiltration were dramatically improved by the aluminum coating layer on CNFs. The aluminum coating formed by the in situ CVD technique was proved to be effective for the fabrication of CNF-reinforced aluminum matrix composites.

  8. Development and compatibility of magnesium matrix fuel plates clad with 6061 aluminum alloy.

    SciTech Connect

    Wiencek, T. C.

    1998-10-22

    Aluminum (Al) is a commonly used matrix for research reactor fuel plates. It has been found that a reaction between the fuel and the aluminum matrix may reduce or increase the irradiation stability of the fuel. To further understand the contribution of the reaction to the irradiation stability, experiments to develop a non-reacting matrix were performed. The work focused on magnesium (Mg), which is an excellent non-reacting matrix candidate and has a neutron absorption coefficient similar to Al. To avoid the formation of a liquid Al/Mg phase, improvements were made to the roll bonding process to achieve acceptable bonding at 415 C. After these methods were developed, fuel plates were produced with two fuels, uranium (U)-2 w/o molybdenum (Mo) and U-10-w/o Mo with two matrices, Al and Mg. A reaction between the magnesium and the 6061 Al cladding was discovered to take place during the processing at 415 C. To minimize the amount of reaction, methods were successfully developed to roll bond the fuel plates at 275 C. No reaction zone was observed in fuel plates processed at 275 C. Using this method, fuel plates with a Mg matrix are planned to be fabricated and included in the next irradiation matrix for the RERTR high density fuel development program.

  9. Inertia-friction welding of a particulate-reinforced aluminum-matrix composite

    NASA Astrophysics Data System (ADS)

    Cola, M. J.; Baeslack, W. A., III; Altshuller, B.; Sjostrom, T.

    Inertia-friction welds were produced between an aluminum-matrix composite tube and a monolithic aluminum alloy bar. The effects of flywheel speed and axial pressure, and the effect of the flywheel speed/axial pressure interaction for a tube-to-bar joint geometry were statistically evaluated. Welds were evaluated with light and scanning-electron microscopy, tensile tested, and measured for hardness. Light microscopy of the interface region of selected inertia-friction welds were sound and free of discontinuities. The tensile strength of the inertia-friction welds was 82 percent of the aluminum-composite base material. Failures were at, or near the weld interface. Fractography of failed tensile specimen fracture surfaces revealed a varying topography and mixed-mode fracture morphology.

  10. Strength variability in alumina fiber-reinforced aluminum matrix composites

    SciTech Connect

    Ramamurty, U.; Zok, F.W.; Leckie, F.A.; Deve, H.E.

    1997-11-01

    The strength variability of an Al-2% Cu alloy matrix reinforced with 65 vol.% Nextel-610 Al{sub 2}O{sub 3} fibers has been investigated, with the aim of identifying and separating the contributions associated with the variabilities in both the fiber bundle strength and the fiber volume fraction. Strength distributions have been measured using three test geometries, including three- and four-point flexure and unixaxial tension. The measured distributions are rationalized on the basis of a fiber strength distribution that follows Weibull statistics and a fiber volume fraction distribution characterized by a Gaussian. The fiber bundle strength distribution is found to be extremely narrow, with a Weibull modulus in the range of {approximately}50--60. In addition, the coefficient of variation in the fiber volume fraction distribution is inferred to be {approximately}6%; by comparison, measurements made on relatively large specimens yield a coefficient of variation of {approximately}3%. The differences in these values are attributed to local volume fraction variations which are not detectable by the global measurements. The measured strengths are compared with the predicted values based on the theoretical work of Curtin and co-workers, incorporating the effects of local load sharing between broken fibers and their neighbors. Good correlations are obtained between the experimental data and the model predictions.

  11. Extreme ultraviolet reflection efficiencies of diamond-turned aluminum, polished nickel, and evaporated gold surfaces. [for telescope mirrors

    NASA Technical Reports Server (NTRS)

    Malina, R. F.; Cash, W.

    1978-01-01

    Measured reflection efficiencies are presented for flat samples of diamond-turned aluminum, nickel, and evaporated gold surfaces fabricated by techniques suited for EUV telescopes. The aluminum samples were 6.2-cm-diameter disks of 6061-T6, the electroless nickel samples were formed by plating beryllium disks with 7.5-microns of Kanigen. Gold samples were produced by coating the aluminum and nickel samples with 5 strips of evaporated gold. Reflection efficiencies are given for grazing angles in the 5-75 degree range. The results indicate that for wavelengths over about 100 A, the gold-coated nickel samples yield highest efficiencies. For shorter wavelengths, the nickel samples yield better efficiencies. 500 A is found to be the optimal gold thickness.

  12. Vacuum brazing of high volume fraction SiC particles reinforced aluminum matrix composites

    NASA Astrophysics Data System (ADS)

    Cheng, Dongfeng; Niu, Jitai; Gao, Zeng; Wang, Peng

    2015-03-01

    This experiment chooses A356 aluminum matrix composites containing 55% SiC particle reinforcing phase as the parent metal and Al-Si-Cu-Zn-Ni alloy metal as the filler metal. The brazing process is carried out in vacuum brazing furnace at the temperature of 550°C and 560°C for 3 min, respectively. The interfacial microstructures and fracture surfaces are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy spectrum analysis (EDS). The result shows that adequacy of element diffusion are superior when brazing at 560°C, because of higher activity and liquidity. Dislocations and twins are observed at the interface between filler and composite due to the different expansion coefficient of the aluminum alloy matrix and SiC particles. The fracture analysis shows that the brittle fracture mainly located at interface of filler and composites.

  13. Strengthening behavior of chopped multi-walled carbon nanotube reinforced aluminum matrix composites

    SciTech Connect

    Shin, S.E.; Bae, D.H.

    2013-09-15

    Strengthening behavior of the aluminum composites reinforced with chopped multi-walled carbon nanotubes (MWCNTs) or aluminum carbide formed during annealing at 500 °C has been investigated. The composites were fabricated by hot-rolling the powders which were ball-milled under various conditions. During the early annealing process, aluminum atoms can cluster inside the tube due to the diffusional flow of aluminum atoms into the tube, providing an increase of the strength of the composite. Further annealing induces the formation of the aluminum carbide phase, leading to an overall drop in the strength of the composites. While the strength of the composites can be evaluated according to the rule of mixture, a particle spacing effect can be additionally imparted on the strength of the composites reinforced with the chopped MWCNTs or the corresponding carbides since the reinforcing agents are smaller than the submicron matrix grains. - Highlights: • Strengthening behavior of chopped CNT reinforced Al-based composites is investigated. • Chopped CNTs have influenced the strength and microstructures of the composites. • Chopped CNTs are created under Ar- 3% H2 atmosphere during mechanical milling. • Strength can be evaluated by the rule of the mixture and a particle spacing effect.

  14. Microstructural and Hardness Study of Pulsed Nd:YAG Laser Surface Alloyed Aluminum with Iron

    NASA Astrophysics Data System (ADS)

    Ansari, Mohammad; Soltani, Reza; Heydarzadeh Sohi, Mahmoud; Valefi, Zia

    2016-04-01

    In the present study, the feasibility of the formation of surface layers containing hard iron aluminides on AA6061-T6 aluminum via pre-plasma spraying with iron and subsequently double surface melting by pulsed Nd:YAG laser is studied. The effects of single and double laser surface melting on microstructure, phase formation, and hardness of the treated layers are examined. Single-step laser treatment resulted in the presence of undissolved iron particles surrounded by lump-like Al5Fe2 and needle-like Al3Fe intermetallic compounds. Double laser surface melting dissolved the retained undissolved irons and resulted in the formation of Al-Al3Fe eutectic structure. Microhardness profiles along cross section and top surface of the treated layers indicated that laser surface alloying with iron enhanced the hardness of the aluminum to more than twice of that of the base material.

  15. Tribological Properties of Aluminum Alloy treated by Fine Particle Peening/DLC Hybrid Surface Modification

    NASA Astrophysics Data System (ADS)

    Amano, Y.; Nanbu, H.; Kameyama, Y.; Komotori, J.

    2010-06-01

    In order to improve the adhesiveness of the DLC coating, Fine Particle Peening (FPP) treatment was employed as pre-treatment of the DLC coating process. FPP treatment was performed using SiC shot particles, and then AA6061-T6 aluminum alloy was DLC-coated. A SiC-rich layer was formed around the surface of the aluminum alloy by the FPP treatment because small chips of shot particles were embedded into the substrate surface. Reciprocating sliding tests were conducted to measure the friction coefficients. While the DLC coated specimen without FPP treatment showed a sudden increase in friction coefficient at the early stage of the wear cycles, the FPP/DLC hybrid treated specimen maintained a low friction coefficient value during the test period. Further investigation revealed that the tribological properties of the substrate after the DLC coating were improved with an increase in the amount of Si at the surface.

  16. Mechanical Properties of Aluminum-Based Dissimilar Alloy Joints by Power Beams, Arc and FSW Processes

    NASA Astrophysics Data System (ADS)

    Okubo, Michinori; Kon, Tomokuni; Abe, Nobuyuki

    Dissimilar smart joints are useful. In this research, welded quality of dissimilar aluminum alloys of 3 mm thickness by various welding processes and process parameters have been investigated by hardness and tensile tests, and observation of imperfection and microstructure. Base metals used in this study are A1050-H24, A2017-T3, A5083-O, A6061-T6 and A7075-T651. Welding processes used are YAG laser beam, electron beam, metal inert gas arc, tungsten inert gas arc and friction stir welding. The properties of weld zones are affected by welding processes, welding parameters and combination of base metals. Properties of high strength aluminum alloy joints are improved by friction stir welding.

  17. Effect of microstructure and notch root radius on fracture toughness of an aluminum metal matrix composite

    NASA Technical Reports Server (NTRS)

    Manoharan, M.; Lewandowski, J. J.

    1989-01-01

    Recent results on the effects of matrix aging condition (matrix temper) and notch root radius on the measured fracture toughness of a SiC particulate reinforced aluminum alloy are reviewed. Stress intensity factors at catastrophic fracture were obtained for both underaged and overaged composites reveal. The linear relation found between apparent fracture toughness and the square root of the notch root radius implies a linear dependence of the crack opening displacement on the notch root radius. The results suggest a strain controlled fracture process, and indicate that there are differences in the fracture micromechanisms of the two aging conditions.

  18. Mueller Matrix of Specular Reflection Using an Aluminum Grating Surface with Oxide Nanofilm.

    PubMed

    Qiu, Jun; Ran, Dongfang; Liu, Linhua; Hsu, Pei-Feng

    2016-06-01

    The accurate nondestructive and real-time determination of the critical dimensions of oxide nanofilms on periodic nanostructures has potential applications in nanofabrication techniques. Mueller ellipsometry is fast, accurate, nondestructive, and can be used in the ambient air. This study used the elements of a Mueller matrix of specular reflection, which is based on a Mueller ellipsometry method, to evaluate the thickness of an oxide nanofilm on an aluminum grating surface. By using non-traditional rigorous coupled-wave analysis (RCWA), we decomposed the Mueller matrix to obtain the relationship between the evaluated polarization properties of reflected light and the dimensions of oxide nanofilms on aluminum grating surfaces. We also quantitatively analyzed the Mueller matrix elements' variation due to the thicknesses of top, sidewall, and bottom oxides. We consider these oxide films are naturally formed and of nonuniform thickness on grating structures. The results show that the elements of Mueller matrix shift with the increasing of the uniform thickness of oxide at a fixed wavelength. Moreover, as oxide nanofilms on grating structures are nonuniform, the impact of the thickness of side wall oxide on the Mueller matrix elements is more obvious than that of top and bottom oxides at the relative larger incidence wavelength range. The finding of this work may facilitate the nondestructive and real-time measurement of the thickness of oxide nanofilms on metal gratings where the metal is easily oxidized. PMID:27129364

  19. Mechanical Properties of Aluminum Matrix Composite Reinforced by Carbothermally Reduced of Fly Ash

    NASA Astrophysics Data System (ADS)

    Jamasri, Wildan, M. W.; Sulardjaka, Kusnanto

    2011-01-01

    The addition of fly ash into aluminum as reinforcement can potentially reduce the production cost and density of aluminum. However, mechanical properties of aluminum matrix composite reinforced by fly ash (MMC ALFA) have some limitations due to the characteristic of fly ash. In this study, a carbothermal reduction process of fly ash and activated carbon powder with particle size <32 μm was performed prior to produce MMC ALFA. The process was carried out in a furnace at 1300° C in vacuum condition under argon flow. Synthesis product was analyzed by XRD with Cu-Kα radiation. From XRD analysis, it shows that the synthesis process can produce SiC powder. The synthesis product was subsequently used as reinforcement particle. Aluminum powder was mixed with 5, 10 and 15% of the synthesized powder, and then uni-axially compacted at pressure of 300 MPa. The compacted product was sintered for 2 hours in argon atmosphere at temperature variation of 550 and 600° C. Flexural strength, hardness and density of MMC ALFA's product were respectively evaluated using a four point bending test method based on ASTM C1161 standard, Brinell hardness scale and Archimedes method. The result of this study shows that the increase of weight of reinforcement can significantly increase the hardness and flexural strength of MMCs. The highest hardness and flexural strength of the MMC product are 300 kg/mm2 and 107.5 MPa, respectively.

  20. Mechanical Properties of Aluminum Matrix Composite Reinforced by Carbothermally Reduced of Fly Ash

    SciTech Connect

    Jamasri; Wildan, M. W.; Sulardjaka; Kusnanto

    2011-01-17

    The addition of fly ash into aluminum as reinforcement can potentially reduce the production cost and density of aluminum. However, mechanical properties of aluminum matrix composite reinforced by fly ash (MMC ALFA) have some limitations due to the characteristic of fly ash. In this study, a carbothermal reduction process of fly ash and activated carbon powder with particle size <32 {mu}m was performed prior to produce MMC ALFA.The process was carried out in a furnace at 1300 deg. C in vacuum condition under argon flow. Synthesis product was analyzed by XRD with Cu-K{sub {alpha}} radiation. From XRD analysis, it shows that the synthesis process can produce SiC powder. The synthesis product was subsequently used as reinforcement particle. Aluminum powder was mixed with 5, 10 and 15% of the synthesized powder, and then uni-axially compacted at pressure of 300 MPa. The compacted product was sintered for 2 hours in argon atmosphere at temperature variation of 550 and 600 deg. C. Flexural strength, hardness and density of MMC ALFA's product were respectively evaluated using a four point bending test method based on ASTM C1161 standard, Brinell hardness scale and Archimedes method. The result of this study shows that the increase of weight of reinforcement can significantly increase the hardness and flexural strength of MMCs. The highest hardness and flexural strength of the MMC product are 300 kg/mm{sup 2} and 107.5 MPa, respectively.

  1. Self-lubricating aluminum metal-matrix composites dispersed with tungsten disulfide and silicon carbide

    SciTech Connect

    Prasad, S.V.; Mecklenburg, K.R.

    1994-07-01

    This paper describes the synthesis and tribological behavior of self-lubricating aluminum alloy metal-matrix composites (MMCs). The formulations of MMCs comprised of tungsten disulfide (WS{sub 2}) and silicon carbide (SiC) particles dispersed in a commercial aluminum alloy (Al-0.40Si-0.75Mg) matrix. Composites were fabricated by a conventional powder metallurgy route involving blending, compacting and sintering. Friction and wear tests (up to a duration of one million cycles) were performed in a ball-on-disk configuration against a steel counterface. Wear scars on MMC disks and steel balls were analyzed in SEM/EDXS. In a dry nitrogen environment, the steady state friction coefficient of an Al-0.10SiC-0.03WS{sub 2}MMC was 0.05, whereas in laboratory air with relative humidity at approximately 65 percent it was 0.10. In both environments, transfer of aluminum to the steel counterface was absent. 20 refs., 12 figs., 2 tabs.

  2. Aluminum-matrix composites with embedded Ni-Ti wires by ultrasonic consolidation

    NASA Astrophysics Data System (ADS)

    Hahnlen, Ryan; Dapino, Marcelo J.; Short, Matt; Graff, Karl

    2009-03-01

    [Smart Vehicle Workshop] This paper presents the development of active aluminum-matrix composites manufactured by Ultrasonic Additive Manufacturing (UAM), an emerging rapid prototyping process based on ultrasonic metal welding. Composites created through UAM experience process temperatures as low as 20°C, in contrast to current metal-matrix fabrication processes which require fusion of materials and hence reach temperatures of 500°C and above. UAM thus creates unprecedented opportunities to develop adaptive structures with seamlessly embedded smart materials and electronic components without degrading the properties that make embedding these materials and components attractive. This research focuses on three aspects of developing UAM Ni-Ti/Al composites which have not been accomplished before: (i) Characterization of the mechanical properties of the composite matrix; (ii) Investigation of Ni-Ti/Al composites as tunable stiffness materials and as strain sensors based on the shape memory effect; and (iii) Development of constitutive models for UAM Ni-Ti/Al composites. The mechanical characterization shows an increase in tensile strength of aluminum UAM builds over the parent material (Al 3003-H18), likely due to grain refinement caused by the UAM process. We demonstrate the ability to embed Ni-Ti wires up to 203 μm in diameter in an aluminum matrix, compared with only 100 μm in previous studies. The resulting Ni-Ti/Al UAM composites have cross sectional area ratios of up to 13.4% Ni-Ti. These composites exhibit a change in stiffness of 6% and a resistivity change of -3% when the Ni- Ti wires undergo martensite to austenite transformation. The Ni-Ti area ratios and associated strength of the shape memory effect are expected to increase as the UAM process becomes better understood and is perfected. The Brinson constitutive model for shape memory transformations is used to describe the stiffness and the strain sensing of Ni-Ti/Al composites in response to

  3. Aluminum Matrix Composites Strengthened with CuZrAgAl Amorphous Atomized Powder Particles

    NASA Astrophysics Data System (ADS)

    Dutkiewicz, Jan; Rogal, Łukasz; Wajda, Wojciech; Kukuła-Kurzyniec, Agata; Coddet, Christian; Dembinski, Lucas

    2015-06-01

    The Al-matrix composites were prepared by hot pressing in vacuum of an aluminum powder with 20 and 40 wt.% addition of the amorphous Cu43Zr43Ag7Al7 alloy (numbers indicate at.%) obtained using gas atomization method. The amorphous structure of the powder was confirmed using x-ray diffraction, DSC, and TEM. The average size of mostly spherical particles was 100 μm, so the powder was sieved to obtain maximum size of 60 μm. The composites were prepared using uniaxial cold pressing in vacuum and at a temperature of 400 °C. The composites of hardness from 43 to 53 HV were obtained for both additions of the amorphous phase. They reached compression strength of 150 MPa for 20% of amorphous phase and 250 MPa for the higher content. The modest hardening effect was caused by crack initiation at Al/amorphous interfaces. The amorphous phase was only partially crystallized in the hot-pressed composites, what did not cause hardness decrease. The application of nanocrystalline aluminum powders obtained by high-energy ball milling for the matrix of composites allowed obtaining nanocrystalline aluminum matrix composites of size near 150 nm, strengthened with the amorphous powders, whose compression strength was near 550 MPa for the composite containing 40% of the amorphous phase and slightly lower for the composite containing 20% of the phase. They showed much higher ductility of 23% in comparison with 7% for the composite containing 40% amorphous phase. The distribution of the strengthening phase in the nanocrystalline matrix was not homogeneous; the amorphous particles formed bands, where majority of cracks nucleated during compression test.

  4. Friction Stir Welding of SiC/Aluminum Metal Matrix Composites

    NASA Technical Reports Server (NTRS)

    Lee, Jonathan A.

    1999-01-01

    Friction Stir Welding (FSW) is a new solid state process for joining metals by plasticizing and consolidating materials around the bond line using thermal energy producing from frictional forces. A feasibility study for FSW of Metal Matrix Composites (MMC) was investigated using aluminum 6092 alloy reinforced with 17% SiC particulates. FSW process consists of a special rotating pin tool that is positioned to plunge into the MMC surface at the bond line. As the tool rotates and move forward along the bond line, the material at the bond line is heated up and forced to flow around the rotating tip to consolidate on the tip's backside to form a solid state joint. FSW has the potential for producing sound welds with MMC because the processing temperature occurs well below the melting point of the metal matrix; thereby eliminating the reinforcement-to-matrix solidification defects, reducing the undesirable chemical reactions and porosity problems.

  5. Aluminum and bone: Review of new clinical circumstances associated with Al(3+) deposition in the calcified matrix of bone.

    PubMed

    Chappard, D; Bizot, P; Mabilleau, G; Hubert, L

    2016-06-01

    Several decades ago, aluminum encephalopathy associated with osteomalacia has been recognized as the major complication of chronic renal failure in dialyzed patients. Removal of aluminum from the dialysate has led to a disappearance of the disease. However, aluminum deposit occurs in the hydroxyapatite of the bone matrix in some clinical circumstances that are presented in this review. We have encountered aluminum in bone in patients with an increased intestinal permeability (coeliac disease), or in the case of prolonged administration of aluminum anti-acid drugs. A colocalisation of aluminum with iron was also noted in cases of hemochromatosis and sickle cell anemia. Aluminium was also identified in a series of patients with exostosis, a frequent benign bone tumor. Corrosion of prosthetic implants composed of grade V titanium (TA6V is an alloy containing 6% aluminum and 4% vanadium) was also observed in a series of hip or knee revisions. Aluminum can be identified in undecalcified bone matrix stained by solochrome azurine, a highly specific stain allowing the detection of 0.03 atomic %. Colocalization of aluminum and iron does not seem to be the fruit of chance but the cellular and molecular mechanisms are still poorly understood. Histochemistry is superior to spectroscopic analyses (EDS and WDS in scanning electron microscopy). PMID:26762722

  6. Graphene-reinforced aluminum matrix composites prepared by spark plasma sintering

    NASA Astrophysics Data System (ADS)

    Tian, Wen-ming; Li, Song-mei; Wang, Bo; Chen, Xin; Liu, Jian-hua; Yu, Mei

    2016-06-01

    Graphene-reinforced 7055 aluminum alloy composites with different contents of graphene were prepared by spark plasma sintering (SPS). The structure and mechanical properties of the composites were investigated. Testing results show that the hardness, compressive strength, and yield strength of the composites are improved with the addition of 1wt% graphene. A clean, strong interface is formed between the metal matrix and graphene via metallurgical bonding on atomic scale. Harmful aluminum carbide (Al4C3) is not formed during SPS processing. Further addition of graphene (above 1wt%) results in the deterioration in mechanical properties of the composites. The agglomeration of graphene plates is exacerbated with increasing graphene content, which is the main reason for this deterioration.

  7. Specific features of the electronic and atomic structures of silicon single crystals in the aluminum matrix

    NASA Astrophysics Data System (ADS)

    Terekhov, V. A.; Lazaruk, S. K.; Usol'tseva, D. S.; Leshok, A. A.; Katsuba, P. S.; Zanin, I. E.; Spirin, D. E.; Stepanova, A. A.; Turishchev, S. Yu.

    2014-12-01

    Films of Al-Si nanocomposites produced by magnetron evaporation of a complex target onto a silicon substrate have been investigated using scanning electron microscopy, X-ray diffraction, ultrasoft X-ray emission spectroscopy, and X-ray absorption near edge structure spectroscopy. It has been found that silicon inclusions are nanocrystals with the mean size of 20-25 nm, with the surface covered by an amorphous silicon layer. The presence of the aluminum matrix in the initial films changes their band structures, in particular, near the bottom of the valence band. After the removal of aluminum, the structure of the valence band becomes identical to that in the bulk material and the structure of the conduction band indicates the presence of a disordered surface layer with a thickness of ˜5 nm.

  8. On Poisson's ratio for metal matrix composite laminates. [aluminum boron composites

    NASA Technical Reports Server (NTRS)

    Herakovich, C. T.; Shuart, M. J.

    1978-01-01

    The definition of Poisson's ratio for nonlinear behavior of metal matrix composite laminates is discussed and experimental results for tensile and compressive loading of five different boron-aluminum laminates are presented. It is shown that there may be considerable difference in the value of Poisson's ratio as defined by a total strain or an incremental strain definition. It is argued that the incremental definition is more appropriate for nonlinear material behavior. Results from a (0) laminate indicate that the incremental definition provides a precursor to failure which is not evident if the total strain definition is used.

  9. Spray-forming monolithic aluminum alloy and metal matrix composite strip

    SciTech Connect

    McHugh, K.M.

    1995-10-01

    Spray forming with de Laval nozzles is an advanced materials processing technology that converts a bulk liquid metal to a near-net-shape solid by depositing atomized droplets onto a suitably shaped substrate. Using this approach, aluminum alloys have been spray formed as strip, with technoeconomic advantages over conventional hot mill processing and continuous casting. The spray-formed strip had a flat profile, minimal porosity, high yield, and refined microstructure. In an adaptation to the technique, 6061 Al/SiC particulate-reinforced metal matrix composite strip was produced by codeposition of the phases.

  10. Wear products that form during tribological tests of aluminum-matrix composite materials

    NASA Astrophysics Data System (ADS)

    Kalashnikov, I. E.; Bolotova, L. K.; Kobeleva, L. I.; Bykov, P. A.; Kolmakov, A. G.

    2015-04-01

    The wear products and the friction surfaces of the composite materials fabricated by reactive casting after the addition of commercial-purity aluminum AD1, titanium and nickel powders, and nanosized modifiers to a matrix melt are studied. The dispersity and the chemical composition of the wear products that form an intermediate layer between the contacting surfaces are analyzed, and the dominating wear mechanisms under experimental tribological loading conditions are determined. It is shown that the formation of such a disperse intermediate layer during lubricant-free friction of the synthesized composite materials decreases the temperature in the tribological contact and ensures a transition from weak to intense wear at higher critical loads.

  11. Cavitation Erosion of Copper, Brass, Aluminum and Titanium Alloys in Mineral Oil

    NASA Technical Reports Server (NTRS)

    Rao, B. C. S.; Buckley, D. H.

    1983-01-01

    The variations of the mean depth of penetration, the mean depth rate of penetration, MDRP, the pit diameter 2a and depth h due to cavitation attack on Al 6061-T6, Cu, brass of composition Cu-35Zn-3Pb and Ti-5A1-2.5Sn are presented. The experiments are conducted in a mineral oil of viscosity 110 CS using a magnetostrictive oscillator of 20 kHz frequency. Based on MDRP on the materials, it is found that Ti-5Al-2.5Sn exhibits cavitation erosion resistance which is two orders of magnitude higher than the other three materials. The values of h/a are the largest for copper and decreased with brass, titanium, and aluminum. Scanning electron microscope studies show that extensive slip and cross slip occurred on the surface prior to pitting and erosion. Twinning is also observed on copper and brass.

  12. The development of an aluminum toroidal shell-type impact limiter

    SciTech Connect

    Mello, R.M.; Wilson, W.K.; Nair, B.R.

    1989-01-01

    The impact limiters on a Type B transportation cask are designed to absorb the impact energy for the 9-meter (30 foot) drop accident conditions without bottoming out in order to limit deceleration loadings on the cask. Toroidal shell-type impact limiters made from stainless steel have been investigated in the past for transportation cask service in Japan (Y. Sugita and S. Mochizuki) and by the General Electric Company (R.J. Pomares, et al.). These designs were relatively heavy and quite rigid causing high deceleration loads on the cask. This paper presents the results of an investigation to determine the feasibility of an aluminum Alloy 6061-T6 toroidal shell impact limiter for a Legal Weight Truck (LWT) cask being developed by the Westinghouse Corporation for the United States Department of Energy. The incentives for the study were the potential advantages such as a compact configuration, lightweight, durability, and essentially maintenance-free operation. 4 refs., 10 figs.

  13. Material failure and inertial instabilities in a shocked imploded cylindrical aluminum sample

    SciTech Connect

    Chandler, E.A.; Egan, P.; Stokes, J.

    1998-12-31

    The authors have used the LANL Pegasus Z-pinch facility to drive a thin cylindrically-convergent Al liner to {approximately}3 km/s to launch {approximately}30 GPa shocks in a 3-mm thick 10-mm-i.d. aluminum cylinder whose interior is filled with 1 atm Xe gas. The subsequent material motion of the metal and gas is diagnosed with both radial and axial flash x-rays and with optical framing cameras. Instabilities are seeded by implanting wires of assorted higher density metal parallel to the cylinder axis. The authors have done two shots, varying the target from Al 1100-O to Al 6061-T6 to explore the effect of changing material strength. The images show the spallation failure of the metal-gas interface on shock release and the effect of the seeded instabilities.

  14. Enhancement of Wettability of Aluminum Based Silicon Carbide Reinforced Particulate Metal Matrix Composite

    NASA Astrophysics Data System (ADS)

    Singh, V. K.; Chauhan, Sakshi; Gope, P. C.; Chaudhary, A. K.

    2015-04-01

    Lately, materials research has shifted to composite materials from monolithic, adjusting to the global need for light weight, low cost, quality, and high performance in structural materials. Every effort aims to develop a material which can be appropriate for various industry and machinery purpose. In the present study, a modest attempt has been made to develop cast aluminum based silicon carbide (SiC) particulate metal matrix composite (MMC) and worked upon to raise the wettability factor between the matrix and dispersion phase. Magnesium (Mg) is used as wetting agent. It works by scavenging the oxygen from dispersoids surface and thinning the gas layer around dispersoids and this is done by forming MgO or MgAl2O4 or both according to concentration of Magnesium added. Mg2Si is the compound responsible for strengthening. The combination of aluminum and magnesium seems to have synergetic effect on wetting and give appropriate strength. All mechanical properties obtained are well correlated with microstructure obtained by Scanning electron micrograph. Differential thermal analysis (DTA) and thermo gravimetric analysis (TGA) also justified the results obtained in present investigations.

  15. Method for embedding optical fibers in an aluminum matrix by ultrasonic consolidation

    NASA Astrophysics Data System (ADS)

    Yen Kong, Choon; Soar, Rupert

    2005-10-01

    The overall aim of the research, part of which is outlined in this paper, was to utilize the ultrasonic consolidation (UC) process for the fabrication of smart metal structures, capable of measuring an external stimulus and responding to this stimulus by adapting its structure accordingly through embedding both active and passive functional elements. This paper presents a fundamental study of embedding methods for the fabrication of optical fibers embedded within aluminum structures. The methods considered in this paper produced embedded optical fiber specimens in which large amounts of plastic flow were observed within the matrix. The matrix material deformed around the fibers, resulting in fully embedded optical fibers capable of transmitting a bright light source and without damaging the fibers. Based on light responses, a general process window was drawn to show the range at which optical fibers can be embedded within aluminum structures using the UC process. The outcomes lay down initial investigative principles for the further development of the technology for embedding or cladding of optical fiber sensors, such as fiber Bragg grating devices, within or on metal structures: for example, the cladding of large free-form metal structures or smart “skinned” metal foam or metal honeycomb structures.

  16. Jet Electrochemical Machining of Particle Reinforced Aluminum Matrix Composites with Different Neutral Electrolytes

    NASA Astrophysics Data System (ADS)

    Hackert-Oschätzchen, M.; Lehnert, N.; Martin, A.; Schubert, A.

    2016-03-01

    Conventional mechanical machining of particle reinforced aluminum matrix composites (AMCs) is challenging because the hard ceramic particles in the soft aluminum matrix lead to an increased tool wear. Furthermore, the mechanical and thermal impact during conventional machining affects the microstructure of the AMCs. Electrochemical machining (ECM) is an alternative method to machine AMCs. Based on anodic dissolution, ECM has a slight influence on the work piece material structure and is independent of material strength and hardness. So the microstructure of the work piece remains unaffected. One method of ECM is electrochemical machining with continuous electrolytic free jet (Jet-ECM). Hereby the electrochemical removal is localized by the geometry of the electrolyte jet. By moving the electrolyte jet micro-structures and microgeometries can be generated quickly and flexibly in metallic parts [1]. Another advantage of Jet-ECM is the low consumption of electrolyte which allows an easy and inexpensive change of electrolyte for investigations with different types of electrolyte. In this study AMCs reinforced with different amounts of SiC-particles are machined with two pH-neutral electrolytes using Jet-ECM. The results provide information about the suitability of the selected electrolytes for the machining of AMCs. In addition, the influence of the particle content on the electrochemical removal result will be evaluated.

  17. The influence of microstructure on the tensile behavior of an aluminum metal matrix composite

    NASA Technical Reports Server (NTRS)

    Birt, Michael J.; Johnson, W. Steven

    1990-01-01

    The relationship between tensile properties and microstructure of a powder metallurgy aluminum alloy, 2009 was examined. The alloy was investigated both unreinforced and reinforced with 15 v/o SiC whiskers or 15 v/o SiC particulate to form a discontinuous metal matrix composite (MMC). The materials were investigated in the as-fabricated condition and in three different hot-rolled sheet thicknesses of 6.35, 3.18, and 1.8 mm. Image analysis was used to characterize the morphology of the reinforcements and their distributions within the matrix alloy. Fractographic examinations revealed that failure was associated with the presence of microstructural inhomogeneities which were related to both the matrix alloy and to the reinforcement. The results from these observations together with the matrix tensile data were used to predict the strengths and moduli of the MMC's using relatively simple models. The whisker MMC could be modeled as a short fiber composite and an attempt was made to model the particulate MMC as a dispersion/dislocation hardened alloy.

  18. Melting and Solidification Behaviour of Bi-Pb Multiphase Alloy Nanoparticles Embedded in Aluminum Matrix.

    PubMed

    Khan, Patan Yousaf; Biswas, Krishanu

    2015-01-01

    The present investigation reports the result of the investigation on the phase transformation of biphasic Bi-Pb alloy nanoparticles embedded in the aluminum matrix. The samples are prepared by rapid solidification route involving melt spinning of Al-6 wt% (Bi55.9Pb44.1) alloy on a rotating copper wheel in an argon-filled evacuated chamber. The detailed transmission electron microscope (TEM) investigation shows presence of near cuboctahedral shaped biphasic nano-inclusions consisting of the (Bi) solid solution and β, the intermediate phase. β constitutes bulk of the nanoparticle with (Bi) forming the cap. Both the phases bear distinct orientation relationship with the matrix. The compositional analysis indicates substantial increase in solid solubilities of Pb in the (Bi) and Bi in the β-phases as compared to the as-cast sample. Differential scanning calorimetric (DSC) studies indicate substantial superheating (16.4 K) of the embedded nanoparticles with appearance of sharp melting peak. The solidification is observed to be diffused, taking place over a large temperature range (344.5 K to 332 K). The in situ heating stage experiments carried out in TEM indicate formation of core shell morphology during heating with β forming the shell around (Bi). The melting starts from Al/β/(Bi) triple point and then the liquid spreads along matrix-particle interface. The solidification occurs in eutectic manner. PMID:26328350

  19. Carbide coated fibers in graphites-aluminum composites. [(fabrication of metal matrix composites)

    NASA Technical Reports Server (NTRS)

    Imprescia, R. J.; Levinson, L. S.; Reiswig, R. D.; Wallace, T. C.; Williams, J. M.

    1976-01-01

    Research activities are described for a NASA-supported program at the Los Alamos Scientific Laboratory to develop graphite fiber-aluminum matrix composites. A chemical vapor deposition apparatus was constructed for continuously coating graphite fibers with TiC. As much as 150 meters of continuously coated fibers were produced. Deposition temperatures were varied from 1365 K to about 1750 K, and deposition time from 6 to 150 seconds. The 6 sec deposition time corresponded to a fiber feed rate of 2.54 m/min through the coater. Thin, uniform, adherent TiC coats, with thicknesses up to approximately 0.1 micrometer were produced on the individual fibers of Thornel 50 graphite yarns without affecting fiber strength. Although coat properties were fairly uniform throughout a given batch, more work is needed to improve the batch-to-batch reproducibility. Samples of TiC-coated Thornel 50 fibers were infiltrated with an aluminum alloy and hot-pressed in vacuum to produce small composite bars for flexure testing. Strengths as high as 90% of the rule-of-mixtures strength were achieved. Results of the examination of the fracture surfaces indicate that the bonding between the aluminum and the TiC-coated fibers is better than that achieved in a similar, commercially infiltrated material made with fibers having no observable surface coats. Several samples of Al-infiltrated, TiC-coated Thornel 50 graphite yarns, together with samples of the commercially infiltrated, uncoated fibers, were heated for 100 hours at temperatures near the alloy solidus. The TiC-coated samples appear to undergo less reaction than do the uncoated samples. Photomicrographs are shown.

  20. Effects of Complex Structured Anodic Oxide Dielectric Layer Grown in Pore Matrix for Aluminum Capacitor.

    PubMed

    Shin, Jin-Ha; Yun, Sook Young; Lee, Chang Hyoung; Park, Hwa-Sun; Suh, Su-Jeong

    2015-11-01

    Anodization of aluminum is generally divided up into two types of anodic aluminum oxide structures depending on electrolyte type. In this study, an anodization process was carried out in two steps to obtain high dielectric strength and break down voltage. In the first step, evaporated high purity Al on Si wafer was anodized in oxalic acidic aqueous solution at various times at a constant temperature of 5 degrees C. In the second step, citric acidic aqueous solution was used to obtain a thickly grown sub-barrier layer. During the second anodization process, the anodizing potential of various ranges was applied at room temperature. An increased thickness of the sub-barrier layer in the porous matrix was obtained according to the increment of the applied anodizing potential. The microstructures and the growth of the sub-barrier layer were then observed with an increasing anodizing potential of 40 to 300 V by using a scanning electron microscope (SEM). An impedance analyzer was used to observe the change of electrical properties, including the capacitance, dissipation factor, impedance, and equivalent series resistance (ESR) depending on the thickness increase of the sub-barrier layer. In addition, the breakdown voltage was measured. The results revealed that dielectric strength was improved with the increase of sub-barrier layer thickness. PMID:26726615

  1. Mechanical behavior of a continuous fiber reinforced aluminum matrix composite subjected to transverse and thermal loading

    NASA Technical Reports Server (NTRS)

    Jansson, S.; Leckie, F. A.

    1991-01-01

    The transverse properties of an aluminum alloy metal matrix composite reinforced by continuous alumina fibers were investigated. The composite is subjected to both mechanical and cyclic thermal loading. The results of an experimental program indicate that the shakedown concept of structural mechanics provides a means of describing the material behavior. When the loading conditions are within the shakedown region, the material finally responds in an elastic manner after initial plastic response, and for loading conditions outside the shakedown region, the material exhibits a rapid incremental plastic strain accumulation. The failure strain varies by an order of magnitude according to the operating conditions. Hence, for high mechanical and low thermal loading, the failure strains is small; for low mechanical and high thermal loading, the failure strain is large.

  2. A study of the composition and microstructure of aluminum matrix composites reinforced with alumina fibers

    NASA Astrophysics Data System (ADS)

    Zolotova, D.; Serpova, V.; Prokofiev, M.; Rabinskiy, L.; Shavnev, A.

    2016-04-01

    This article presents the results of a study of the microstructure and the composition of aluminum-based metal matrix composites (MMC) reinforced with continuous alumina fibers. An Al-Mg-Cu alloy similar to that of AA 2024 was used. X-ray diffraction and X-ray fluorescence analyses were used for investigation of a probable volume fraction of a spinel phase in MMC. Scanning electron microscopy and an X-ray microanalysis were used to study a change of the elemental composition of the composites microstructure on the polished cross sections. The constant mass fractions of magnesium (0.65 wt. %) and copper (1.25 wt. %) were found in the interphase area within radius of 1 μm around fibers.

  3. Modification of cast aluminum-matrix composite materials by refractory nanoparticles

    NASA Astrophysics Data System (ADS)

    Chernyshova, T. A.; Kobeleva, L. I.; Kalashnikov, I. E.; Bolotova, L. K.

    2009-02-01

    The effect of SiO2 and Al2O3 oxide ceramic nanoparticles on the solidification of model samples based on a commercial D16 alloy is studied. The composite samples are fabricated by reaction casting when titanium, nickel, and ceramic powders are mixed with an aluminum melt. The grain size in a matrix, the size and shape of Al3Ti intermetallic inclusions, and the interphase distances in eutectics are determined with optical and scanning electron microscopes. A certain modifying effect of oxide ceramic nanoparticles on the structure of model CMs during their in situ formation is detected, and the inoculation effect of SiO2 added to a melt on the reaction products is most pronounced.

  4. Mechanical behavior and processing of aluminum metal-matrix composites. Final report, 1 Jan 89-31 Dec 91

    SciTech Connect

    Lavernia, E.J.; Mohamed, F.A.

    1992-02-21

    The objectives of the present three year research program were threefold. First the program sought to explore the potential of using spray atomization and deposition to process aluminum metal matrix composites, not only with improved mechanical properties, but also with specifications suitable for applications of interest to the Army; these applications include light weight armor vehicles, helicopter engines and other structural components. Second, the research program sought to develop an in-depth understanding of the various physical phenomena that occur during spray atomization and deposition of aluminum metal matrix composites. Third, the program sought to provide insight the fundamental mechanisms governing the elevated temperature deformation behavior, not only of metal matrix composites processed by spray atomization and deposition, but also of metal matrix composites in general.

  5. Grain structure and dislocation density measurements in a friction stir welded aluminum alloy using x-ray peak profile analysis

    SciTech Connect

    Woo, Wan Chuck; Balogh, Levente; Ungar, Prof Tomas; Choo, Hahn; Feng, Zhili

    2008-01-01

    The dislocation density and grain structure of a friction stir welded 6061-T6 aluminum alloy was determined as a function of distance from the weld centerline using high-resolution micro-beam x-ray diffraction. The results of the x-ray peak profile analysis show that the dislocation density is about 1.2 x 10^14 m-2 inside and 4.8 x 10^14 m-2 outside of the weld region. The average subgrain size is about 180 nm in both regions. Compared to the base material, the dislocation density was significantly decreased in the dynamic recrystallized zone of the friction stir welds, which is a good correlation with the TEM observations. The influence of the dislocation density on the strain hardening behavior during tensile deformation is also discussed.

  6. Forging limits for an aluminum matrix composite; Part 1: Experimental results

    SciTech Connect

    Syu, D.G.C.; Ghosh, A.K. )

    1994-09-01

    Forging limits in a discontinuously reinforced aluminum (DRA) matrix composite, 2014 Al/15 vol pct Al[sub 2]O[sub 3], were determined by compressing samples of various cylindrical geometries under different conditions of temperature, strain rate, and lubrication and measuring the limit strains attained prior to incipient crack formation. In some cases, circumferential grids were machined on the sample surface to obtain the local fracture strain states. Crack formation was caused by the secondary tensile stresses; however, crack propagation was relatively slow and somewhat more severe at 300 C than at 400 C. The forging limit of the composite was found to be higher at 400 C than at 300 C and also higher at slower strain rates. The plane-strain forging limit of the composite at 300 C and a strain rate of 0.5 s[sup [minus]1] was less than 0.05, while that of the matrix was higher than 0.5. It was found that the forging limits can be influenced by the depth of the circumferential grids and can be lower than those for the smooth surface samples.

  7. The influence of matrix microstructure and particle reinforcement on the creep behavior of 2219 aluminum

    NASA Astrophysics Data System (ADS)

    Krajewski, P. E.; Allison, J. E.; Jones, J. W.

    1993-12-01

    The influence of matrix microstructure and reinforcement with 15 vol pct of TiC particles on the creep behavior of 2219 aluminum has been examined in the temperature range of 150 ‡C to 250 ‡C. At 150 ‡C, reinforcement led to an improvement in creep resistance, while at 250 ‡C, both materials exhibited essentially identical creep behavior. Precipitate spacing in the matrix exerted the predominant influence on minimum creep rate in both the unreinforced and the reinforced materials over the temperature range studied. This behavior and the high-stress dependence of minimum creep rate are explained using existing constant structure models where, in the present study, precipitate spacing is identified as the pertinent substructure dimension. A modest microstructure-independent strengthening from particle reinforcement was observed at 150 ‡C and was accurately modeled by existing continuum mechanical models. The absence of reinforcement creep strengthening at 250 ‡C can be attributed to diffusional relaxation processes at the higher temperature.

  8. Analysis of stress-strain, fracture and ductility behavior of aluminum matrix composites containing discontinuous silicon carbide reinforcement

    NASA Technical Reports Server (NTRS)

    Mcdanels, D. L.

    1984-01-01

    Mechanical properties and stress-strain behavior for several types of commercially fabricated aluminum matrix composites, containing up to 40 vol % discontinuous SiC whisker, nodule, or particulate reinforcement were evaluated. It was found that the elastic modulus of the composites was isotropic, to be independent of type of reinforcement, and to be controlled solely by the volume percentage of SiC reinforcement present. The yield/tensile strengths and ductility were controlled primarily by the matrix alloy and temper condition. Ductility decreased with increasing reinforcement content, however, the fracture strains observed were higher than those reported in the literature for this type of composite. This increase in fracture strain is attributed to cleaner matrix powder and increased mechanical working during fabrication. Conventional aluminum and titanium structural alloys were compared and have shown that the properties of these low cost, lightweight composites have good potential for application to aerospace structures.

  9. Manufacturing of Aluminum Matrix Composites Reinforced with Iron Oxide (Fe3O4) Nanoparticles: Microstructural and Mechanical Properties

    NASA Astrophysics Data System (ADS)

    Bayraktar, Emin; Ayari, Fayza; Tan, Ming Jen; Tosun-Bayraktar, Ayse; Katundi, Dhurata

    2014-04-01

    The purpose of this paper is to demonstrate the low-cost manufacturing of aluminum matrix composites reinforced with nano iron oxide as light and efficient materials for engineering applications. It is very desirable to use reinforced aluminum matrix composites in structural applications (automotive, aeronautical, etc.) because of their outstanding stiffness-to-weight and strength-to-weight ratios. In modern industry, it is increasingly important to develop new composites as alternative materials to fabricate multifunctional pieces. Detailed information is presented on the manufacturing process of this composite, and a preliminary study was performed on the cryogenic-cycling behavior to evaluate the interface between the matrix and the reinforcement. Microindentation tests were carried out to evaluate the micromechanical properties of these materials; a simple and practical finite element model is proposed to predict certain parameters related to the composition of the composite.

  10. Mechanical characterization of copper coated carbon nanotubes reinforced aluminum matrix composites

    SciTech Connect

    Maqbool, Adnan; Hussain, M. Asif; Khalid, F. Ahmad; Bakhsh, Nabi; Hussain, Ali; Kim, Myong Ho

    2013-12-15

    In this investigation, carbon nanotube (CNT) reinforced aluminum composites were prepared by the molecular-level mixing process using copper coated CNTs. The mixing of CNTs was accomplished by ultrasonic mixing and ball milling. Electroless Cu-coated CNTs were used to enhance the interfacial bonding between CNTs and aluminum. Scanning electron microscope analysis revealed the homogenous dispersion of Cu-coated CNTs in the composite samples compared with the uncoated CNTs. The samples were pressureless sintered under vacuum followed by hot rolling to promote the uniform microstructure and dispersion of CNTs. In 1.0 wt.% uncoated and Cu-coated CNT/Al composites, compared to pure Al, the microhardness increased by 44% and 103%, respectively. As compared to the pure Al, for 1.0 wt.% uncoated CNT/Al composite, increase in yield strength and ultimate tensile strength was estimated about 58% and 62%, respectively. However, in case of 1.0 wt.% Cu-coated CNT/Al composite, yield strength and ultimate tensile strength were increased significantly about 121% and 107%, respectively. - Graphical Abstract: Copper coated CNTs were synthesized by the electroless plating process. Optimizing the plating bath to (1:1) by wt CNTs with Cu, thickness of Cu-coated CNTs has been reduced to 100 nm. Cu-coated CNTs developed the stronger interfacial bonding with the Al matrix which resulted in the efficient transfer of load. Highlights: • Copper coated CNTs were synthesized by the electroless plating process. • Thickness of Cu-coated CNTs has been reduced to 100 nm by optimized plating bath. • In 1.0 wt.% Cu-coated CNT/Al composite, microhardness increased by 103%. • Cu-coated CNTs transfer load efficiently with stronger interfacial bonding. • In 1.0 wt.% Cu-coated CNT/Al composite, Y.S and UTS increased by 126% and 105%.

  11. Measurement of Mercury in Flue Gas Based on an Aluminum Matrix Sorbent

    PubMed Central

    Wang, Juan; Xu, Wei; Wang, Xiaohao; Wang, Wenhua

    2011-01-01

    The measurement of total mercury in flue gas based on an economical aluminum matrix sorbent was developed in this paper. A sorbent trap consisted of three tubes was employed to capture Hg from flue gas. Hg trapped on sorbent was transferred into solution by acid leaching and then detected by CVAAS. Hg adsorbed on sorbent was recovered completely by leaching process. The 87.7% recovery of Hg in flue gas by tube 1 and tube 2 was obtained on the equipment of coal combustion and sampling in lab. In order to evaluate the ability to recover and accurately quantify Hg0 on the sorbent media, the analytical bias test on tube 3 spiked with Hg0 was also performed and got the average recovery of 97.1%. Mercury measurements based on this method were conducted for three coal-fired power plants in China. The mercury in coal is distributed into bottom ash, electrostatic precipitator (ESP) ash, wet flue gas desulfurization (WFGD) reactant, and flue gas, and the relative distribution varied depending on factors such as the coal type and the operation conditions of plants. The mercury mass balances of three plants were also calculated which were 91.6%, 77.1%, and 118%, respectively. The reliability of this method was verified by the Ontario Hydro (OH) method either in lab or in field. PMID:22235178

  12. Laser direct marking applied to rasterizing miniature Data Matrix Code on aluminum alloy

    NASA Astrophysics Data System (ADS)

    Li, Xia-Shuang; He, Wei-Ping; Lei, Lei; Wang, Jian; Guo, Gai-Fang; Zhang, Teng-Yun; Yue, Ting

    2016-03-01

    Precise miniaturization of 2D Data Matrix (DM) Codes on Aluminum alloy formed by raster mode laser direct part marking is demonstrated. The characteristic edge over-burn effects, which render vector mode laser direct part marking inadequate for producing precise and readable miniature codes, are minimized with raster mode laser marking. To obtain the control mechanism for the contrast and print growth of miniature DM code by raster laser marking process, the temperature field model of long pulse laser interaction with material is established. From the experimental results, laser average power and Q frequency have an important effect on the contrast and print growth of miniature DM code, and the threshold of laser average power and Q frequency for an identifiable miniature DM code are respectively 3.6 W and 110 kHz, which matches the model well within normal operating conditions. In addition, the empirical model of correlation occurring between laser marking parameters and module size is also obtained, and the optimal processing parameter values for an identifiable miniature DM code of different but certain data size are given. It is also found that an increase of the repeat scanning number effectively improves the surface finish of bore, the appearance consistency of modules, which has benefit to reading. The reading quality of miniature DM code is greatly improved using ultrasonic cleaning in water by avoiding the interference of color speckles surrounding modules.

  13. Effects of SiC whiskers and particles on precipitation in aluminum matrix composites

    NASA Astrophysics Data System (ADS)

    Papazian, John M.

    1988-12-01

    The age-hardening precipitation reactions in aluminum matrix composites reinforced with discontinuous SiC were studied using a calorimetric technique. Composites fabricated with 2124, 2219, 6061, and 7475 alloy matrices were obtained from commercial sources along with unreinforced control materials fabricated in a similar manner. The 7475 materials were made by a casting process while the others were made by powder metallurgy: the SiC reinforcement was in the form of whiskers or particulate. It was found that the overall age-hardening sequence of the alloy was not changed by the addition of SiC, but that the volume fractions of various phases and the precipitation kinetics were substantially modified. Precipitation and dissolution kinetics were generally accelerated. A substantial portion of this acceleration was found to be due to the powder metallurgy process employed to make the composites, but the formation kinetics of some particular precipitate phases were also strongly affected by the presence of SiC. It was observed that the volume fraction of GP zones able to form in the SiC containing materials was significantly reduced. The presence of SiC particles also caused normally quench insensitive materials such as 6061 to become quench sensitive. The microstructural origins of these effects are discussed.

  14. Evaluation of the Technical-Economic Potential of Particle- Reinforced Aluminum Matrix Composites and Electrochemical Machining

    NASA Astrophysics Data System (ADS)

    Schubert, A.; Götze, U.; Hackert-Oschätzchen, M.; Lehnert, N.; Herold, F.; Meichsner, G.; Schmidt, A.

    2016-03-01

    Compared to conventional cutting, the processing of materials by electrochemical machining offers some technical advantages like high surface quality, no thermal or mechanical impact on the work piece and preservation of the microstructure of the work piece material. From the economic point of view, the possibility of process parallelization and the absence of any process-related tool wear are mentionable advantages of electrochemical machining. In this study, based on experimental results, it will be evaluated to what extent the electrochemical machining is technically and economically suitable for the finish-machining of particle- reinforced aluminum matrix composites (AMCs). Initial studies showed that electrochemical machining - in contrast to other machining processes - has the potential to fulfil demanding requirements regarding precision and surface quality of products or components especially when applied to AMCs. In addition, the investigations show that processing of AMCs by electrochemical machining requires less energy than the electrochemical machining of stainless steel. Therefore, an evaluation of electrochemically machined AMCs - compared to stainless steel - from a technical and an economic perspective will be presented in this paper. The results show the potential of electro-chemically machined AMCs and contribute to the enhancement of instruments for technical-economic evaluations as well as a comprehensive innovation control.

  15. Impact Delamination and Fracture in Aluminum/Acrylic Sandwich Plates

    NASA Technical Reports Server (NTRS)

    Liaw, Benjamin; Zeichner, Glenn; Liu, Yanxiong; Bowles, Kenneth J. (Technical Monitor)

    2000-01-01

    Impact-induced delamination and fracture in 6061-T6 aluminum/cast acrylic sandwich plates adhered by epoxy were generated in an instrumented drop-weight impact machine. Although only a small dent was produced on the aluminum side when a hemispherical penetrator tup was dropped onto it from a couple of inches, a large ring of delamination at the interface was observed. The delamination damage was often accompanied by severe shattering in the acrylic substratum. Damage patterns in the acrylic layer include radial and ring cracks and, together with delamination at the interface, may cause peeling-off of acrylic material from the sandwich plate. Theory of stress-wave propagation can be used to explain these damage patterns. The impact tests were conducted at various temperatures. The results also show clearly that temperature effect is very important in impact damage. For pure cast acrylic nil-ductile transition (NDT) occurs between 185-195 F. Excessive impact energy was dissipated into fracture energy when tested at temperature below this range or through plastic deformation when tested at temperature above the NDT temperature. Results from this study will be used as baseline data for studying fiber-metal laminates, such as GLARE and ARALL for advanced aeronautical and astronautical applications.

  16. Tailoring Microstructure and Properties of Hierarchical Aluminum Metal Matrix Composites Through Friction Stir Processing

    NASA Astrophysics Data System (ADS)

    Sohn, Y. H.; Patterson, T.; Hofmeister, C.; Kammerer, C.; Mohr, W.; van den Bergh, M.; Shaeffer, M.; Seaman, J.; Cho, K.

    2012-02-01

    The fabrication of hierarchical aluminum metal matrix composites (MMCs) begins with the cryomilling of inert gas-atomized AA5083 Al powders with B4C particles, which yields agglomerates of nanocrystalline (NC) Al grains containing a uniform dispersion of solidly bonded, submicron B4C particles. The cryomilled agglomerates are size classified, blended with coarse-grain Al (CG-Al) powders, vacuum degassed at an elevated temperature, and consolidated to form the bulk composite. This hierarchical Al MMCs have low weight and high strength/stiffness attributable to the (A) Hall-Petch strengthening from NC-Al (5083) grains, (B) Zener pinning effects from B4C particulate reinforcement and dispersoids in both the NC-Al and CG-Al, (C) the interface characteristics between the three constituents, and (D) a high dislocation density. The hierarchical Al MMCs exhibit good thermal stability and microstructural characteristics that deflect or blunt crack propagation. A significant change in the microstructure of the composite was observed after friction stir processing (FSP) in the thermomechanically affected zone (TMAZ) due to the mechanical mixing, particularly in the advancing side of the stir zone (SZ). The NC-Al grains in the TMAZ grew during FSP. Evidence of CG-Al size reduction was also documented since CG-Al domain was absent by optical observation. Given the proper control of the microstructure, FSP has demonstrated its potential to increase both strength and ductility, and to create functionally tailored hierarchical MMCs through surface modification, graded structures, and other hybrid microstructural design.

  17. Control of self-propagating high-temperature synthesis derived aluminum-titanium carbide metal matrix composites

    NASA Astrophysics Data System (ADS)

    Garrett, William

    Self-propagating High-temperature Synthesis (SHS) is a combustion process that can be used to form Metal Matrix Composite (MMC) reinforcing phases in situ. Generally, the kinetic processes in these reactions are poorly understood but are affected by reactant particle size, reactant green density, reactant stoichiometry, reaction preheat temperature, and reaction product cooling rate. These reaction parameters also affect the microstructure of the reaction products because of changes in the rate of heat evolution, reaction rate, surface area available for heterogeneous nucleation, reaction temperature, and the stable phases during and after the reaction. Post-reaction processes affecting the microstructure and properties of the SHS products include densification, melt alloying (SHS reaction products are used as a master alloy), and die casting techniques. Matrix alloy additions should be controlled to prevent unwanted reactions between the matrix and the reinforcement. In the present study, Ti + C + X → TiC + X (X = Al or TiC) is the SHS reaction system studied, with varying amounts of Al (10-50wt%) or TiC (0-20wt%) added to the reactants as a thermal diluent. Addition of these diluents decreases the reaction temperatures and decreases the TiC reinforcing particle size and interaction during particle growth. A method of direct thermal analysis of the self-heating behavior of diluted SHS reactions is developed and compared to existing methods used to measure the apparent activation energy of single step SHS reactions. The activation energies are used to determine a probable reaction path for Ti + C + Al → TiC + Al. SHS reaction products of various diluent concentrations are analyzed for TiC particle size and shape. SHS reaction products containing 55v% TiC - 45v% Al are dispersed as a master alloy in aluminum melts; reaction products containing higher concentrations of TiC particles are difficult to disperse. To show compatibility with the TiC reinforcing

  18. Measurement of the thermal contact conductance and thermal conductivity of anodized aluminum coatings

    SciTech Connect

    Peterson, G.P.; Fletcher, L.S. )

    1990-08-01

    An experimental investigation was conducted to determine the thermal contact conductance and effective thermal conductivity of anodized coatings. One chemically polished Aluminum 6061-T6 test specimen and seven specimens with anodized coatings varying in thickness from 60.9 {mu}m to 163.8 {mu}m were tested while in contact with a single unanodized aluminum surface. Measurements of the overall joint conductance, composed of the thermal contact conductance between the anodized coating and the bare aluminum surface and the bulk conductance of the coating material, indicated that the overall joint conductance decreased with increasing thickness of the anodized coating and increased with increasing interfacial load. Using the experimental data, a dimensionless expression was developed that related the overall joint conductance to the coating thickness, the surface roughness, the interfacial pressure, and the properties of the aluminum substrate. By subtracting the thermal contact conductance from the measured overall joint conductance, estimations of the effective thermal conductivity of the anodized coating as a function of pressure were obtained for each of the seven anodized specimens. At an extrapolated pressure of zero, the effective thermal conductivity was found to be approximately 0.02 W/m-K. In addition to this extrapolated value, a single expression for predicting the effective thermal conductivity as a function of both the interface pressure and the anodized coating thickness was developed and shown to be within {plus minus}5 percent of the experimental data over a pressure range of 0 to 14 MPa.

  19. A method for studying weld fusion boundary microstructure evolution in aluminum alloys

    SciTech Connect

    Kostrivas, A.; Lippold, J.C.

    2000-01-01

    Aluminum alloys may exhibit a variety of microstructures within the fusion zone adjacent to the fusion boundary. Under conventional weld solidification conditions, epitaxial nucleation occurs off grains in the heat-affected zone (HAZ) and solidification proceeds along preferred growth directions. In some aluminum alloys, such as those containing Li and Zr, a nondendritic equiaxed grain zone (EQZ) has been observed along the fusion boundary that does not nucleate epitaxially from the HAZ substrate. The EQZ has been the subject of considerable study because of its susceptibility to cracking during initial fabrication and repair. The motivation of this investigation was to develop a technique that would allow the nature and evolution of the fusion boundary to be studied under controlled thermal conditions. A melting technique was developed to simulate the fusion boundary of aluminum alloys using the Gleeble{reg{underscore}sign} thermal simulator. Using a steel sleeve to contain the aluminum, samples wee heated to incremental temperatures above the solidus temperature of a number of alloys. In Alloy 2195, a 4Cu-1Li alloy, an EQZ could be formed by heating in the temperature range approximately from 630--640 C. At temperatures above 640 C, solidification occurred by the normal epitaxial nucleation and growth mechanism. Fusion boundary behavior was also studied in Alloys 5454-H34, 6061-T6 and 2219-T8. Nucleation in these alloys was observed to be epitaxial. Details of the technique and its effectiveness for performing controlled melting experiments at incremental temperatures above the solidus are described.

  20. Corrosion and wear resistance of titanium- and aluminum-based metal matrix composites fabricated by direct metal laser deposition

    NASA Astrophysics Data System (ADS)

    Waldera, Benjamin L.

    Titanium- and Aluminum-based metal matrix composites (MMC) have shown favorable properties for aerospace applications such as airframes, reinforcement materials and joining elements. In this research, such coatings were developed by direct metal laser deposition with a powder-fed fiber coupled diode laser. The MMC formulations consisted of pure titanium and aluminum matrices with reinforcing powder blends of chromium carbide and tungsten carbide nickel alloy. Two powder formulations were investigated for each matrix material (Ti1, Ti2, Al1 and Al2). Titanium based composites were deposited onto a Ti6Al4V plate while aluminum composites were deposited onto AA 7075 and AA 5083 for Al1 and Al2, respectively. Microstructures of the MMCs were studied by optical and scanning electron microscopy. The hardness and reduced Young's modulus (Er) were assessed through depth-sensing instrumented nanoindentation. microhardness (Vickers) was also analyzed for each composite. The corrosion resistance of the MMCs were compared by monitoring open circuit potential (OCP), polarization resistance (Rp) and potentiodynamic polarization in 0.5 M NaCl to simulate exposure to seawater. The Ti-MMCs demonstrated improvements in hardness between 205% and 350% over Ti6Al4V. Al-MMCs showed improvements between 47% and 79% over AA 7075 and AA 5083. The MMCs showed an increase in anodic current density indicating the formation of a less protective surface oxide than the base metals.

  1. Corrosion of Continuous Fiber Reinforced Aluminum Metal Matrix Composites (CF-AMCs)

    NASA Astrophysics Data System (ADS)

    Tiwari, Shruti

    The first objective of this research is to study the atmospheric corrosion behavior of continuous reinforced aluminum matrix composites (CF-AMCs). The materials used for this research were alumina (Al2O3) and nickel (Ni) coated carbon (C) fibers reinforced AMCs. The major focus is to identify the correlation between atmospheric parameters and the corrosion rates of CF-AMCs in the multitude of microclimates and environments in Hawai'i. The micro-structures of CF-AMCs were obtained to correlate the microstructures with their corrosion performances. Also electrochemical polarization experiments were conducted in the laboratory to explain the corrosion mechanism of CF-AMCs. In addition, CF-AMCs were exposed to seven different test sites for three exposure periods. The various climatic conditions like temperature (T), relative humidity (RH), rainfall (RF), time of wetness (TOW), chloride (Cl- ) and sulfate (SO42-) deposition rate, and pH were monitored for three exposure period. Likewise, mass losses of CF-AMCs at each test site for three exposure periods were determined. The microstructure of the CF-AMCS showed that Al/C/50f MMCs contained a Ni-rich phase in the matrix, indicating that the Ni coating on the C fiber dissolved in the matrix. The intermetallic phases obtained in Al-2wt% Cu/Al 2O3/50f-T6 MMC and Al-2wt%-T6 monolith were rich in Cu and Fe. The intermetallic phases obtained in Al 7075/Al2O3/50f-T6 MMC and Al 7075-T6 monolith also contained traces of Mg, Zn, Ni, and Si. Electrochemical polarization experiment indicated that the Al/Al 2O3/50f Al-2wt% Cu/Al2O3/50f-T6 and Al 7075/Al2O3/50f-T6 MMC showed similar corrosion trends as their respective monoliths pure Al, Al-2wt%-T6 and Al 7075-T6 in both aerated and deaerated condition. Al2O3 fiber, being an insulator, did not have a great effect on the polarization behavior of the composites. Al/C/50f MMCs corroded at a much faster rate as compared to pure Al monolith due to the galvanic effect between C and Al

  2. Corrosion of Continuous Fiber Reinforced Aluminum Metal Matrix Composites (CF-AMCs)

    NASA Astrophysics Data System (ADS)

    Tiwari, Shruti

    The first objective of this research is to study the atmospheric corrosion behavior of continuous reinforced aluminum matrix composites (CF-AMCs). The materials used for this research were alumina (Al2O3) and nickel (Ni) coated carbon (C) fibers reinforced AMCs. The major focus is to identify the correlation between atmospheric parameters and the corrosion rates of CF-AMCs in the multitude of microclimates and environments in Hawai'i. The micro-structures of CF-AMCs were obtained to correlate the microstructures with their corrosion performances. Also electrochemical polarization experiments were conducted in the laboratory to explain the corrosion mechanism of CF-AMCs. In addition, CF-AMCs were exposed to seven different test sites for three exposure periods. The various climatic conditions like temperature (T), relative humidity (RH), rainfall (RF), time of wetness (TOW), chloride (Cl- ) and sulfate (SO42-) deposition rate, and pH were monitored for three exposure period. Likewise, mass losses of CF-AMCs at each test site for three exposure periods were determined. The microstructure of the CF-AMCS showed that Al/C/50f MMCs contained a Ni-rich phase in the matrix, indicating that the Ni coating on the C fiber dissolved in the matrix. The intermetallic phases obtained in Al-2wt% Cu/Al 2O3/50f-T6 MMC and Al-2wt%-T6 monolith were rich in Cu and Fe. The intermetallic phases obtained in Al 7075/Al2O3/50f-T6 MMC and Al 7075-T6 monolith also contained traces of Mg, Zn, Ni, and Si. Electrochemical polarization experiment indicated that the Al/Al 2O3/50f Al-2wt% Cu/Al2O3/50f-T6 and Al 7075/Al2O3/50f-T6 MMC showed similar corrosion trends as their respective monoliths pure Al, Al-2wt%-T6 and Al 7075-T6 in both aerated and deaerated condition. Al2O3 fiber, being an insulator, did not have a great effect on the polarization behavior of the composites. Al/C/50f MMCs corroded at a much faster rate as compared to pure Al monolith due to the galvanic effect between C and Al

  3. Avoidance of stress corrosion susceptibility in high strength aluminum alloys by control of grain boundary and matrix microstructure

    NASA Technical Reports Server (NTRS)

    Adler, P.; Deiasi, R.

    1974-01-01

    The relation of microstructure to the mechanical strength and stress corrosion resistance of highest strength and overaged tempers of BAR and 7050 aluminum alloys was investigated. Comparison is made with previously studied 7075 aluminum alloy. Optical microscopy, transmission electron microscopy, and differential scanning calorimetry were used to characterize the grain morphology, matrix microstructure, and grain boundary microstructure of these tempers. Grain boundary interparticle spacing was significant to stress corrosion crack propagation for all three alloys; increasing interparticle spacing led to increased resistance to crack propagation. In addition, the fire grain size in Bar and 7050 appears to enhance crack propagation. The highest strength temper of 7050 has a comparatively high resistance to crack initiation. Overall stress corrosion behavior is dependent on environment pH, and evaluation over a range of pH is recommended.

  4. Microstructure of arc brazed and diffusion bonded joints of stainless steel and SiC reinforced aluminum matrix composite

    NASA Astrophysics Data System (ADS)

    Elßner, M.; Weis, S.; Grund, T.; Wagner, G.; Habisch, S.; Mayr, P.

    2016-03-01

    Joint interfaces of aluminum and stainless steel often exhibit intermetallics of Al-Fe, which limit the joint strength. In order to reduce these brittle phases in joints of aluminum matrix composites (AMC) and stainless steel, diffusion bonding and arc brazing are used. Due to the absence of a liquid phase, diffusion welding can reduce the formation of these critical in- termetallics. For this joining technique, the influence of surface treatments and adjusted time- temperature-surface-pressure-regimes is investigated. On the other hand, arc brazing offers the advantage to combine a localized heat input with the application of a low melting filler and was conducted using the system Al-Ag-Cu. Results of the joining tests using both approaches are described and discussed with regard to the microstructure of the joints and the interfaces.

  5. Optimization of the strength-fracture toughness relation in particulate-reinforced aluminum composites via control of the matrix microstructure

    NASA Astrophysics Data System (ADS)

    Dutta, I.; McNelley, T. R.; Nagarajan, R.; Quiles, F. N.

    1998-09-01

    The evolution of the microstructure and mechanical properties of a 17.5 vol. pct SiC particulate-reinforced aluminum alloy 6092-matrix composite has been studied as a function of postfabrication processing and heat treatment. It is demonstrated that, by the control of particulate distribution, matrix grain, and substructure and of the matrix precipitate state, the strength-toughness combination in the composite can be optimized over a wide range of properties, without resorting to unstable, underaged (UA) matrix microstructures, which are usually deemed necessary to produce a higher fracture toughness than that displayed in the peak-aged condition. Further, it is demonstrated that, following an appropriate combination of thermomechanical processing and unconventional heat treatment, the composite may possess better stiffness, strength, and fracture toughness than a similar unreinforced alloy. In the high- and low-strength matrix microstructural conditions, the matrix grain and substructure were found to play a substantial role in determining fracture properties. However, in the intermediate-strength regime, properties appeared to be optimizable by the utilization of heat treatments only. These observations are rationalized on the basis of current understanding of the grain size dependence of fracture toughness and the detailed microstructural features resulting from thermomechanical treatments.

  6. Stir mixing and pressureless infiltration synthesis of aluminum alloy metal matrix nanocomposites

    NASA Astrophysics Data System (ADS)

    Schultz, Benjamin Franklin

    2009-12-01

    Pressureless liquid metal infiltration of suitably packed compacts of spherical shaped 47 nm size 70:30 Delta:Gamma Al2O3 mixed with a 7/2 ratio of elemental Al and Mg powders was used to study (i) the kinetics of pressureless infiltration processing of Al2O 3 nanoparticle-A206 alloy composites, (ii) the optimal processing variables to maximize material property responses, (iii) the development of multimodal microstructures in terms of feature size. The major experimental variables included: infiltration temperature (850 to 950°C), infiltration time (1--5 hours), and powder composition (0--50 wt% Al2O 3). All experiments were conducted under UHP nitrogen atmosphere. Under the conditions studied, compacts with a maximum of 20 wt% nanoparticles were successfully infiltrated with A206 alloy aluminum, and the degree of infiltration measured by the percentage of residual porosity depended on infiltration time, temperature and nanoparticle content. By examining responses including percent porosity, and macrohardness, empirical models for correlating processing conditions with material properties and microstructure were developed. The addition of increasing weight percentage of Al2O3 nanoparticles resulted in a decrease in the coefficient of thermal expansion greater than that predicted by the rule of mixtures due to the mechanical constraint of the nanoparticles on the matrix. Likewise, the damping capacity of the 10 wt% and 20 wt% reinforced nanocomposites increased with increasing weight percentage up to 280% greater than the base alloy. The key microstructural observations in the pressureless infiltrated composites include: (1) a bimodal structure of micro-scale grains, exhibiting Al-Cu-Mg precipitates dispersed within the grains; (2) amorphous and crystalline interfaces between the Al-alloy grains and the nanocomposite regions; (3) infiltrated nanoparticle agglomerates having nanoscale channels forming a nanoscale substructure; (4) mixed nanoscale reinforcements of

  7. Applicability of ultrasonic testing for the determination of volume fraction of particulates in alumina-reinforced aluminum matrix composites

    SciTech Connect

    Fang, C.K.; Fang, R.L.; Weng, W.P.; Chuang, T.H.

    1999-10-01

    An ultrasonic testing technique was employed to determine the volume fraction of alumina particulate reinforcement in 6061 aluminum matrix composites. this study was performed on various composites with Al{sub 2}O{sub 3} nominal volume fractions of 10, 15, and 20%. For comparison, other techniques were employed as well, including the Archimedes method, metallographic image analysis, X-ray diffraction, and acid dissolution. Observations indicated that ultrasonic testing and acid dissolution methods are more reliable than the other techniques, while ultrasonic testing is faster than the acid dissolution method.

  8. Ballistic Experiments with Titanium and Aluminum Targets

    SciTech Connect

    Gogolewski, R.; Morgan, B.R.

    1999-11-23

    During the course of the project we conducted two sets of fundamental experiments in penetration mechanics in the LLNL Terminal Ballistics Laboratory of the Physics Directorate. The first set of full-scale experiments was conducted with a 14.5mm air propelled launcher. The object of the experiments was to determine the ballistic limit speed of 6Al-4V-alloy titanium, low fineness ratio projectiles centrally impacting 2024-T3 alloy aluminum flat plates and the failure modes of the projectiles and the targets. The second set of one-third scale experiments was conducted with a 14.5mm powder launcher. The object of these experiments was to determine the ballistic limit speed of 6Al-4V alloy titanium high fineness ratio projectiles centrally impacting 6Al-4V alloy titanium flat plates and the failure modes of the projectiles and the target. We employed radiography to observe a projectile just before and after interaction with a target plate. Early on, we employed a non-damaging ''soft-catch'' technique to capture projectiles after they perforated targets. Once we realized that a projectile was not damaged during interaction with a target, we used a 4-inch thick 6061-T6-alloy aluminum witness block with a 6.0-inch x 6.0-inch cross-section to measure projectile residual penetration. We have recorded and tabulated below projectile impact speed, projectile residual (post-impact) speed, projectile failure mode, target failure mode, and pertinent comments for the experiments. The ballistic techniques employed for the experiments are similar to those employed in an earlier study.

  9. Compressive strength, plastic flow properties, and surface frictional effects of 1100, 3003 and 6061 aluminum alloys

    SciTech Connect

    Pinkerton, G.W.

    1993-12-31

    The purpose of this study is to find aluminum alloys that are effective for use as wire vacuum seals in the 800MeV particle accelerator located at the Louis Anderson Meson Physics Facility (LAMPF) in Los Alamos, NM. Three alloys, Al 1100, Al 3003, and Al 6061, are investigated under uniaxial compression to determine stresses for a given height reduction from 0 to 70 percent, and to find plastic flow and surface interaction effects. Right-circular cylindrical specimens are compressed on-end (cylindrically) and radially (for modeling as compressed wire). Aluminum 1100 and 3003 alloys are compared for length to diameter ratios of 1 and 2 for both compression types, and are then compared to results of radial compression of annealed small diameter Al 1100 wire currently used at LAMPE. The specimens are also compressed between three different platen surfaces, polished steel, etched steel, and aluminum 6061-T6, to determine effects of friction. The Al 3003 alloy exhibits 20 to 25% lower stresses at all height reductions than Al 1100 for both cylindrical and radial compression.

  10. The corrosion protection of aluminum by various anodizing treatments

    NASA Technical Reports Server (NTRS)

    Danford, Merlin D.

    1989-01-01

    Corrosion protection to 6061-T6 aluminum, afforded by both teflon-impregnated anodized coats (Polylube and Tufram) and hard-anodized coats (water sealed and dichromate sealed), was studied at both pH 5.5 and pH 9.5, with an exposure period of 28 days in 3.5 percent NaCl solution (25 C) for each specimen. In general, corrosion protection for all specimens was better at pH 9.5 than at pH 5.5. Protection by a Tufram coat proved superior to that afforded by Polylube at each pH, with corrosion protection by the hard-anodized, water-sealed coat at pH 9.5 providing the best protection. Electrochemical work in each case was corroborated by microscopic examination of the coats after exposure. Corrosion protection by Tufram at pH 9.5 was most comparable to that of the hard-anodized samples, although pitting and some cracking of the coat did occur.

  11. Modelling hypervelocity impacts into aluminum structures based on LDEF data

    NASA Technical Reports Server (NTRS)

    Coombs, C. R.; Atkinson, D. R.; Watts, A. J.; Wagner, J. R.; Allbrooks, M. K.; Hennessy, C. J.

    1993-01-01

    Realizing and understanding the effects of the near-Earth space environment on a spacecraft during its mission lifetime is becoming more important with the regeneration of America's space program. Included among these potential effects are the following: erosion and surface degradation due to atomic oxygen impingement; ultraviolet exposure embrittlement; and delamination, pitting, cratering, and ring formation due to micrometeoroid and debris impacts. These effects may occur synergistically and may alter the spacecraft materials enough to modify the resultant crater, star crack, and/or perforation. This study concentrates on modelling the effects of micrometeoroid and debris hypervelocity impacts into aluminum materials (6061-T6). Space debris exists in all sizes, and has the possibility of growing into a potentially catastrophic problem, particularly since self-collisions between particles can rapidly escalate the number of small impactors. We have examined the morphologies of the Long Duration Exposure Facility (LDEF) impact craters and the relationship between the observed impact damage on LDEF versus the existing models for both the natural (micrometeoroid) and manmade (debris) environments in order to better define these environments.

  12. 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.

  13. In-situ deformation studies of an aluminum metal-matrix composite in a scanning electron microscope

    NASA Technical Reports Server (NTRS)

    Manoharan, M.; Lewandowski, J. J.

    1989-01-01

    Tensile specimens made of a metal-matrix composite (cast and extruded aluminum alloy-based matrix reinforced with Al2O3 particulate) were tested in situ in a scanning electron microscope equipped with a deformation stage, to directly monitor the crack propagation phenomenon. The in situ SEM observations revealed the presence of microcracks both ahead of and near the crack-tip region. The microcracks were primarily associated with cracks in the alumina particles. The results suggest that a region of intense deformation exists ahead of the crack and corresponds to the region of microcracking. As the crack progresses, a region of plastically deformed material and associated microcracks remains in the wake of the crack.

  14. Friction Stir Welding for Aluminum Metal Matrix Composites (MMC's) (Center Director's Discretionary Fund, Project No. 98-09)

    NASA Technical Reports Server (NTRS)

    Lee, J. A.; Carter, R. W.; Ding, J.

    1999-01-01

    This technical memorandum describes an investigation of using friction stir welding (FSW) process for joining a variety of aluminum metal matrix composites (MMC's) reinforced with discontinuous silicon-carbide (SiC) particulate and functional gradient materials. Preliminary results show that FSW is feasible to weld aluminum MMC to MMC or to aluminum-lithium 2195 if the SiC reinforcement is <25 percent by volume fraction. However, a softening in the heat-affected zone was observed and is known to be one of the major limiting factors for joint strength. The pin tool's material is made from a low-cost steel tool H-13 material, and the pin tool's wear was excessive such that the pin tool length has to be manually adjusted for every 5 ft of weldment. Initially, boron-carbide coating was developed for pin tools, but it did not show a significant improvement in wear resistance. Basically, FSW is applicable mainly for butt joining of flat plates. Therefore, FSW of cylindrical articles such as a flange to a duct with practical diameters ranging from 2-5 in. must be fully demonstrated and compared with other proven MMC joining techniques for cylindrical articles.

  15. Effect of low-velocity or ballistic impact damage on the strength of thin composite and aluminum shear panels

    NASA Technical Reports Server (NTRS)

    Farley, G. L.

    1985-01-01

    Impact tests were conducted on shear panels fabricated from 6061-T6 aluminum and from woven fabric prepreg of Du Pont Kevlara fiber/epoxy resin and graphite fiber/epoxy resin. The shear panels consisted of three different composite laminates and one aluminum material configuration. Three panel aspect ratios were evaluated for each material configuration. Composite panels were impacted with a 1.27-cm (0.05-in) diameter aluminum sphere at low velocities of 46 m/sec (150 ft/sec) and 67 m/sec (220 ft/sec). Ballistic impact conditions consisted of a tumbled 0.50-caliber projectile impacting loaded composite and aluminum shear panels. The results of these tests indicate that ballistic threshold load (the lowest load which will result in immediate failure upon penetration by the projectile) varied between 0.44 and 0.61 of the average failure load of undamaged panels. The residual strengths of the panels after ballistic impact varied between 0.55 and 0.75 of the average failure strength of the undamaged panels. The low velocity impacts at 67 m/sec (220 ft/sec) caused a 15 to 20 percent reduction in strength, whereas the impacts at 46 m/sec (150 ft/sec) resulted in negligible strength loss. Good agreement was obtained between the experimental failure strengths and the predicted strength with the point stress failure criterion.

  16. Characterization of an Effective Cleaning Procedure for Aluminum Alloys: Surface Enhanced Raman Spectroscopy and Zeta Potential Analysis

    SciTech Connect

    Cherepy, N J; Shen, T H; Esposito, A P; Tillotson, T M

    2004-06-02

    We have developed a cleaning procedure for aluminum alloys for effective minimization of surface-adsorbed sub-micron particles and non-volatile residue. The procedure consists of a phosphoric acid etch followed by an alkaline detergent wash. To better understand the mechanism whereby this procedure reduces surface contaminants, we characterized the aluminum surface as a function of cleaning step using Surface Enhanced Raman Spectroscopy (SERS). SERS indicates that phosphoric acid etching re-establishes a surface oxide of different characteristics, including deposition of phosphate and increased hydration, while the subsequent alkaline detergent wash appears to remove the phosphate and modify the new surface oxide, possibly leading to a more compact surface oxide. We also studied the zeta potential of <5 micron pure aluminum and aluminum alloy 6061-T6 particles to determine how surface electrostatics may be affected during the cleaning process. The particles show a decrease in the magnitude of their zeta potential in the presence of detergent, and this effect is most pronounced for particles that have been etched with phosphoric acid. This reduction in magnitude of the surface attractive potential is in agreement with our observation that the phosphoric acid etch followed by detergent wash results in a decrease in surface-adsorbed sub-micron particulates.

  17. Temperature-dependence mechanism of tensile strength of Si-Ti-C-O fiber-aluminum matrix composites

    SciTech Connect

    Ochiai, Shojiro; Hojo, Masaki; Osamura, Kozo; Matsunaga, Kenji; Waku, Yoshiharu; Yamamura, Takemi

    1995-03-01

    The mechanism for the temperature dependence of the tensile strength of unidirectional hybrid type Si-Ti-C-O (Tyranno) fiber-reinforced aluminum matrix composite, in which SiC-particles are dispersed in the matrix, is discussed, focusing on the temperature dependencies of the stress concentration arising from broken fibers and critical length and their influences on the composite strength, by means of a shear-lag analysis and a Monte Carlo simulation. The main results are summarized as follows. The softening of the matrix at high temperatures raises the composite strength from the point of decrease in stress concentration, but on the other hand, it also reduces strength from the point of increase in critical length, which reduces the stress-carrying capacity of broken fibers over a long distance. The reason why the measured strength of composite decreased with increasing temperature could be attributed to the predominancy of the latter effect over the former one. The results of the simulation indicated that the hybridization of the composites improved room-temperature and high-temperature strengths through the strengthening of the matrix.

  18. Temperature-dependence mechanism of tensile strength of Si-Ti-C-0 Fiber-Aluminum matrix composites

    NASA Astrophysics Data System (ADS)

    Ochiai, Shojiro; Matsunaga, Kenji; Waku, Yoshiharu; Yamamura, Takemi; Hojo, Masaki; Osamura, Kozo

    1995-03-01

    The mechanism for the temperature dependence of the tensile strength of unidirectional hybrid type Si-Ti-C-O (Tyranno) fiber-reinforced aluminum matrix composite, in which SiC-particles are dispersed in the matrix, is discussed, focusing on the temperature dependencies of the stress concentration arising from broken fibers and critical length and their influences on the composite strength, by means of a shear-lag analysis and a Monte Carlo simulation. The main results are summarized as follows. The softening of the matrix at high temperatures raises the composite strength from the point of decrease in stress concentration, but on the other hand, it also reduces strength from the point of increase in critical length, which reduces the stress-carrying capacity of broken fibers over a long distance. The reason why the measured strength of composite decreased with increasing temperature could be attributed to the predominacy of the latter effect over the former one. The results of the simulation indicated that the hybridization of the composites improved room-temperature and high-temperature strengths through the strengthening of the matrix.

  19. Transient Liquid-Phase Diffusion Bonding of Aluminum Metal Matrix Composite Using a Mixed Cu-Ni Powder Interlayer

    NASA Astrophysics Data System (ADS)

    Maity, Joydeep; Pal, Tapan Kumar

    2012-07-01

    In the present study, the transient liquid-phase diffusion bonding of an aluminum metal matrix composite (6061-15 wt.% SiCp) has been investigated for the first time using a mixed Cu-Ni powder interlayer at 560 °C, 0.2 MPa, for different holding times up to 6 h. The microstructure of the isothermally solidified zone contains equilibrium precipitate CuAl2, metastable precipitate Al9Ni2 in the matrix of α-solid solution along with the reinforcement particles (SiC). On the other hand, the microstructure of the central bond zone consists of equilibrium phases such as NiAl3, Al7Cu4Ni and α-solid solution along with SiC particles (without any segregation) and the presence of microporosities. During shear test, the crack originates from microporosities and propagates along the interphase interfaces resulting in poor bond strength for lower holding times. As the bonding time increases, with continual diffusion, the structural heterogeneity is diminished, and the microporosities are eliminated at the central bond zone. Accordingly, after 6-h holding, the microstructure of the central bond zone mainly consists of NiAl3 without any visible microporosity. This provides a joint efficiency of 84% with failure primarily occurring through decohesion at the SiC particle/matrix interface.

  20. Effect of an absorbent overlay on the residual stress field induced by laser shock processing on aluminum samples

    NASA Astrophysics Data System (ADS)

    Rubio-González, C.; Gomez-Rosas, G.; Ocaña, J. L.; Molpeceres, C.; Banderas, A.; Porro, J.; Morales, M.

    2006-07-01

    Laser shock processing (LSP) or laser shock peening is a new technique for strengthening metals. This process induces a compressive residual stress field, which increases fatigue crack initiation life and reduces fatigue crack growth rate. Specimens of 6061-T6 aluminum alloy are used in this investigation. A convergent lens is used to deliver 2.5 J, 8 ns laser pulses by a Q-switch Nd:YAG laser, operating at 10 Hz. The pulses are focused to a diameter of 1.5 mm onto aluminum samples. Density of 2500 pulses/cm 2 with infrared (1064 nm) radiation was used. The effect of an absorbent overlay on the residual stress field using this LSP setup and this energy level is evaluated. Residual stress distribution as a function of depth is assessed by the hole drilling method. It is observed that the overlay makes the compressive residual stress profile move to the surface. This effect is explained on the basis of the vaporization of the coat layer suppressing thermal effects on the metallic substrate. The effect of coating the specimen surface before LSP treatment may have advantages on improving wear and contact fatigue properties of this aluminum alloy.

  1. A Comparison Between ECAP and Conventional Extrusion for Consolidation of Aluminum Metal Matrix Composite

    NASA Astrophysics Data System (ADS)

    Haghighi, R. Derakhshandeh; Jahromi, S. A. Jenabali; Moresedgh, A.; Khorshid, M. Tabandeh

    2012-09-01

    In this study, two powder consolidation techniques, equal channel angular pressing (ECAP) and extrusion, were utilized to consolidate attritioned aluminum powder and Al-5 vol.% nano-Al2O3 composite powder. The effect of ECAP and extrusion on consolidation behavior of composite powder and mechanical properties of subsequent compacts are presented. It is found that three passes of ECAP in tube at 200 °C is capable of consolidating the composite to 99.29% of its theoretical density whereas after hot extrusion of the composite the density reached to 98.5% of its theoretical density. Moreover, extrusion needs higher temperature and pressing load in comparison to the ECAP method. Hardness measurements show 1.7 and 1.2 times higher microhardness for the consolidated composite and pure aluminum after ECAP comparing with the extruded ones, respectively. Microstructural investigations and compression tests demonstrate stronger bonds between the particles after three passes of ECAP than the extrusion. Furthermore, the samples after three passes of ECAP show better wear resistance than the extruded ones.

  2. B -spline R -matrix-with-pseudostates calculations for electron collisions with aluminum

    NASA Astrophysics Data System (ADS)

    Gedeon, Viktor; Gedeon, Sergej; Lazur, Vladimir; Nagy, Elizabeth; Zatsarinny, Oleg; Bartschat, Klaus

    2015-11-01

    A systematic study of angle-integrated cross sections for electron scattering from neutral aluminum is presented. The calculations cover elastic scattering, excitation of the 14 states (3 s2n p ) P2o (n =3 ,4 ,5 ,6 ) , (3 s2n s ) 2S (n =4 ,5 ,6 ) , (3 s2n d ) 2D (n =3 ,4 ) , (3 s 3 p2)P,24,2D,2S , and (3 s24 f ) F2o , as well as electron impact ionization. The sensitivity of the results to changes in the theoretical model is checked by comparing predictions from a variety of approximations, including a large-scale model with over 500 continuum pseudostates. The current results are believed to be accurate at the few-percent level and should represent a sufficiently extensive set of electron collision data for most modeling applications involving neutral aluminum.

  3. Calorimetric studies of 7000 series aluminum alloys. I - Matrix precipitate characterization of 7075. II - Comparison of 7075, 7050, and RX720 alloys

    NASA Technical Reports Server (NTRS)

    Deiasi, R.; Adler, P. N.

    1977-01-01

    Correlation between differential scanning calorimetry and high temperature transmission electron microscopy for the characterization of preexisting matrix precipitates in the highest-strength and overaged tempers of 7075 aluminum was demonstrated. The solid state reactions undergone by these tempers in the 20-500 C temperature range were elucidated and expressed in terms of thermodynamic and kinetic parameters. The dissolution parameters for each phase are distinguishable and serve as guidelines for a rapid characterization of the matrix microstructure of these alloys.

  4. Energy-Saving Melting and Revert Reduction Technology (E-SMARRT): Development of Elevated Temperature Aluminum Metal Matrix Composite (MMC) Alloy and Its Processing Technology

    SciTech Connect

    Weiss, David C.; Gegal, Gerald A.

    2014-04-15

    The objective of this project was to provide a production capable cast aluminum metal matrix composite (MMC) alloy with an operating temperature capability of 250-300°C. Important industrial sectors as well as the military now seek lightweight aluminum alloy castings that can operate in temperature ranges of 250-300°C. Current needs in this temperature range are being satisfied by the use of titanium alloy castings. These have the desired strength properties but the end components are heavier and significantly more costly. Also, the energy requirements for production of titanium alloy castings are significantly higher than those required for production of aluminum alloys and aluminum alloy castings.

  5. Sintering Behavior of Hypereutectic Aluminum-Silicon Metal Matrix Composites Powder

    NASA Astrophysics Data System (ADS)

    Rudianto, Haris; Sun, Yang Sang; Jin, Kim Yong; Woo, Nam Ki

    Lightweight materials of Aluminum-Silicon P/M alloys offer the advantage of high-wear resistance, high strength, good temperature resistance, and a low coefficient of thermal expansion. An A359 MMC alloy was mixed together with Alumix 231 in this research. Powders were compacted with compaction pressure up to 700 MPa. Particle size and compaction pressure influenced green density. Compacted powders were sintered in a tube furnace under a flowing nitrogen gas. Sintering temperature, heating rate and sintering time were verified to determine best sintering conditions of the alloys. Chemical composition also contributed to gain higher sintered density. Precipitation strengthening method was used to improve mechanical properties of this materials.T6 heat treatment was carried out to produce fine precipitates to impede movement of dislocation. The chemical composition of this materials allow for the potential formation of several strengthening precipitates including θ (Al2Cu) and β (Mg2Si).

  6. Optimal welding parameters for very high power ultrasonic additive manufacturing of smart structures with aluminum 6061 matrix

    NASA Astrophysics Data System (ADS)

    Wolcott, Paul J.; Hehr, Adam; Dapino, Marcelo J.

    2014-03-01

    Ultrasonic additive manufacturing (UAM) is a recent solid state manufacturing process that combines ad- ditive joining of thin metal tapes with subtractive milling operations to generate near net shape metallic parts. Due to the minimal heating during the process, UAM is a proven method of embedding Ni-Ti, Fe-Ga, and PVDF to create active metal matrix composites. Recently, advances in the UAM process utilizing 9 kW very high power (VHP) welding has improved bonding properties, enabling joining of high strength materials previously unweldable with 1 kW low power UAM. Consequently, a design of experiments study was conducted to optimize welding conditions for aluminum 6061 components. This understanding is critical in the design of UAM parts containing smart materials. Build parameters, including weld force, weld speed, amplitude, and temperature were varied based on a Taguchi experimental design matrix and tested for me- chanical strength. Optimal weld parameters were identi ed with statistical methods including a generalized linear model for analysis of variance (ANOVA), mean e ects plots, and interaction e ects plots.

  7. Damping mechanisms in alumina borate whisker-reinforced-aluminum matrix composites with or without SnO{sub 2} coatings

    SciTech Connect

    Hu, J.; Wang, X. F.; Zheng, Z. Z.

    2010-01-15

    SnO{sub 2} was successfully coated on the surface of alumina borate whiskers. The pure aluminum matrix composites reinforced with a SnO{sub 2}-coated alumina borate whisker were fabricated by squeeze casting. The effects of coating contents on the damping properties of the coated composites at various temperatures, frequencies, and strain amplitudes were examined. The microstructures of the coated composites were also investigated through transmission electron microscopy observations. These results indicate that the introduction of Sn at the interface between whisker and matrix in the coated composites during the squeeze casting process alters not only the interface structures but also the dislocation status of the matrices in the vicinity of the interface. The results of damping characterization indicate that the damping capacities of the coated composites strongly depend on the coating contents and strain amplitudes. A damping peak at low temperatures appeared not only in the coated composites but also in the noncoated one, which is related to dislocation motion and interfacial slip caused by Sn. A damping peak at high temperatures appeared only in the coated composites, and the damping mechanisms at high temperature change with the increase in strain amplitudes. Sn played an important role on the damping mechanisms of the coated composites all along.

  8. Approach to In- Situ Producing Reinforcing Phase Within an Active-Transient Liquid Phase Bond Seam for Aluminum Matrix Composite

    NASA Astrophysics Data System (ADS)

    Zhang, Guifeng; Liao, Xianjin; Chen, Bo; Zhang, Linjie; Zhang, Jianxun

    2015-06-01

    To optimize the braze composition design route for aluminum matrix composite, the feasibility of in situ producing reinforcing phase within the transient liquid phase bond seam matrix, by adding active melting point increaser (MPI, e.g., Ti) together with general melting point depressant (MPD, e.g., Cu) into the interlayer, was demonstrated. For SiC p /A356 composite, by comparing the wettability, joint microstructure, joint shear strength, and fracture path for the developed Al-19Cu-1Ti, Al-19Cu, Al-33Cu-1Ti, Al-33Cu (wt pct), and commercial Cu foils as interlayer, the feasibility of in situ producing reinforcing phase within the bond seam by adding Ti was demonstrated. Especially for Al-19Cu-1Ti active braze, small and dispersed ternary aluminide of Al-Si-Ti phase was obtained within the bond seam as in situ reinforcement, leading to a favorable fracture path within SiC p /A356, not along the initial interface or within the bond seam. For the formation mechanism of the in situ reinforcing phase of MPI-containing intermetallic compound within the bond seam, a model of repeating concentration-precipitation-termination-engulfment during isothermal solidification is proposed.

  9. Crack initiation and growth toughness of an aluminum metal-matrix composite

    NASA Technical Reports Server (NTRS)

    Manoharan, M.; Lewandowski, J. J.

    1990-01-01

    The effects of systematic changes in matrix microstructure on crack initiation and growth toughnesses were determined on an Al-Zn-Mg-Cu alloy containing 0, 15, 20 percent by volume of SiC particulates. Materials were heat treated to underaged (UA) and overaged (OA) conditions of equivalent matrix microhardness and flow stress. Although both the fracture initiation and growth toughnesses, as measured by JIc and tearing modulus, were similar for the unreinforced materials in the UA and OA conditions, significant effects of microstructure on both JIc and tearing modulus were observed in the composites. SEM and TEM observations of fracture paths in the two conditions are utilized to rationalize these observations in light of existing theories of ductile fracture propagation.

  10. Consolidation of Carbon Nanotube Reinforced Aluminum Matrix Composites by High-Pressure Torsion

    NASA Astrophysics Data System (ADS)

    Asgharzadeh, Hamed; Joo, Soo-Hyun; Kim, Hyoung Seop

    2014-08-01

    Al-3 vol pct carbon nanotube (CNT) composites are fabricated by consolidation through high-pressure torsion (HPT) at room temperature. The densification behavior, microstructural evolution, and mechanical properties of Al/CNT composites are studied. The results show that density and microstructural homogeneity increase with increasing number of revolutions under a high pressure of 6 GPa. Substantial grain refinement is achieved after 10 turns of HPT with an average grain thickness of ~38 nm perpendicular to the compression axis of HPT. The Al/CNT composite shows a considerable increase in hardness and strength compared to the Al matrix. The strengthening mechanisms of the Al/CNT composite are found to be (i) grain refinement of Al matrix and (ii) Orowan looping. Raman spectroscopy and high-resolution transmission electron microscopy reveal that the structure of most of CNTs is changed during processing through mechanical milling and HPT.

  11. Effect of fiber diameter and matrix alloys on impact-resistant boron/aluminum composites

    NASA Technical Reports Server (NTRS)

    Mcdanels, D. L.; Signorelli, R. A.

    1976-01-01

    Efforts to improve the impact resistance of B/Al are reviewed and analyzed. Nonstandard thin-sheet charpy and Izod impact tests and standard full-size Charpy impact tests were conducted on composites containing unidirectional 0.10mm, 0.14mm, and 0.20mm diameter boron fibers in 1100, 2024, 5052, and 6061 Al matrices. Impact failure modes of B/Al are proposed in an attempt to describe the mechanisms involved and to provide insight for maximizing impact resistance. The impact strength of B/Al was significantly increased by proper selection of materials and processing. The use of a ductile matrix and large diameter boron fibers gave the highest impact strengths. This combination resulted in improved energy absorption through matrix shear deformation and multiple fiber breakage.

  12. Fracture behavior of notched continuous fiber boron/aluminum metal matrix composite. Ph.D. Thesis

    SciTech Connect

    Hsieh, F.

    1994-01-01

    One of the most useful attribute of reinforced fibrous composites is its ability to retard crack propagation and thereby improve its overall fracture resistance. Research on the fracture behavior of continuous fiber reinforced metal matrix composites (MMC`s) is critical to assessing important engineering properties such as fatigue, impact resistance, creep and durability. The mechanism of interfacial fiber/matrix sliding and debonding in a notched fiber reinforced composite and the corresponding increasing of the overall fracture toughness have been studied in recent years. However, to the best of the authors knowledge, no direct in-situ experimental measurement of the interfacial sliding and debonding processes has been conducted so far. Although, some qualitative description and analyses have been performed by many researchers. In this research, moire interferometry, which is capable of full field surface deformation measurement, is applied to study the interfacial fracture behavior of unidirectional continuous fiber B/Al MMC at room temperature. The objectives of this research are (1) to analyze the mechanisms of interfacial fiber/matrix sliding and debonding, and (2) to investigate the failure criterion for interfacial sliding/debonding based on the measured full-strength high resolution moire fringe patterns at notch tip region. A hybrid finite element analysis is also conducted to compare and verify the experimental results. The test results indicated the existence of a critical interfacial shear strain to initiate the T-crack growth. And numerical results compared favorably with experimental results were noted.

  13. High temperature dynamic modulus and damping of aluminum and titanium matrix composites

    NASA Technical Reports Server (NTRS)

    Dicarlo, J. A.; Maisel, J. E.

    1979-01-01

    Dynamic modulus and damping capacity property data were measured from 20 to over 500 C for unidirectional B/Al (1100), B/Al (6061), B/SiC/Al (6061), Al2O3/Al, SiC/Ti-6Al-4V, and SiC/Ti composites. The measurements were made under vacuum by the forced vibration of composite bars at free-free flexural resonance near 2000 Hz and at amplitudes below 0.000001. Whereas little variation was observed in the dynamic moduli of specimens with approximately the same fiber content (50 percent), the damping of B/Al composites was found at all temperatures to be significantly greater than the damping of the Al2O3/Al and SiC/Ti composites. For those few situations where slight deviations from theory were observed, the dynamic data were examined for information concerning microstructural changes induced by composite fabrication and thermal treatment. The 270 C damping peak observed in B/Al (6061) composites after heat treatment above 460 C appears to be the result of a change in the 6061 aluminum alloy microstructure induced by interaction with the boron fibers. The growth characteristics of the damping peak suggest its possible value for monitoring fiber strength degration caused by excess thermal treatment during B/Al (6061) fabrication and use.

  14. Surface-modified anodic aluminum oxide membrane with hydroxyethyl celluloses as a matrix for bilirubin removal.

    PubMed

    Xue, Maoqiang; Ling, Yisheng; Wu, Guisen; Liu, Xin; Ge, Dongtao; Shi, Wei

    2013-01-01

    Microporous anodic aluminum oxide (AAO) membranes were modified by 3-glycidoxypropyltrimethoxysilane to produce terminal epoxy groups. These were used to covalently link hydroxyethyl celluloses (HEC) to amplify reactive groups of AAO membrane. The hydroxyl groups of HEC-AAO composite membrane were further modified with 1,4-butanediol diglycidyl ether to link arginine as an affinity ligand. The contents of HEC and arginine of arginine-immobilized HEC-AAO membrane were 52.1 and 19.7mg/g membrane, respectively. As biomedical adsorbents, the arginine-immobilized HEC-AAO membranes were tested for bilirubin removal. The non-specific bilirubin adsorption on the unmodified HEC-AAO composite membranes was 0.8mg/g membrane. Higher bilirubin adsorption values, up to 52.6mg/g membrane, were obtained with the arginine-immobilized HEC-AAO membranes. Elution of bilirubin showed desorption ratio was up to 85% using 0.3M NaSCN solution as the desorption agent. Comparisons equilibrium and dynamic capacities showed that dynamic capacities were lower than the equilibrium capacities. In addition, the adsorption mechanism of bilirubin and the effects of temperature, initial concentration of bilirubin, albumin concentration and ionic strength on adsorption were also investigated. PMID:23290920

  15. Monotonic and cyclic fatigue properties of automotive aluminum alloys

    SciTech Connect

    Wong, W.A.

    1984-01-01

    Monotonic and strain-controlled fatigue tests were conducted on 2014-T6, 6061-T6 and 7175-T73 hand-forgings, 5052-H32 and 6061-T6 sheet, and a 1983/84 production Chevrolet Corvette upper-control-arm-pivot shaft (UCAPS) cold-forged from 5454-H12 and 6061-T4 rolled rod (the 6061 UCAPS was artificially-aged to the -T6 temper, after forging). Various monotonic and cyclic fatigue stress-strain material properties are presented. The responses of the various alloys and product-forms in terms of cyclic hardening or softening are described.

  16. Preparation of Aluminum Metal Matrix Composite with Novel In situ Ceramic Composite Particulates, Developed from Waste Colliery Shale Material

    NASA Astrophysics Data System (ADS)

    Venkata Siva, S. B.; Sahoo, K. L.; Ganguly, R. I.; Dash, R. R.; Singh, S. K.; Satpathy, B. K.; Srinivasarao, G.

    2013-08-01

    A novel method is adapted to prepare an in situ ceramic composite from waste colliery shale (CS) material. Heat treatment of the shale material, in a plasma reactor and/or in a high temperature furnace at 1673 K (1400 °C) under high vacuum (10-6 Torr), has enabled in situ conversion of SiO2 to SiC in the vicinity of carbon and Al2O3 present in the shale material. The composite has the chemical constituents, SiC-Al2O3-C, as established by XRD/EDX analysis. Particle sizes of the composite range between 50 nm and 200 μm. The shape of the particles vary, presumably rod to spherical shape, distributed preferably in the region of grain boundaries. The CS composite so produced is added to aluminum melt to produce Al-CS composite (12 vol. pct). For comparison of properties, the aluminum metal matrix composite (AMCs) is made with Al2O3 particulates (15 vol. pct) with size <200 μm. The heat-treated Al-CS composite has shown better mechanical properties compared to the Al-Al2O3 composite. The ductility and toughness of the Al-CS composite are greater than that of the Al-Al2O3 composite. Fractographs revealed fine sheared dimples in the Al-CS composite, whereas the same of the Al-Al2O3 composite showed an appearance of cleavage-type facets. Abrasion and frictional behavior of both the composites have been compared. The findings lead to the conclusion that the in situ composite developed from the colliery shale waste material has a good future for its use in AMCs.

  17. Environment enhanced fatigue of advanced aluminum alloys and metal matrix composites

    NASA Technical Reports Server (NTRS)

    Slavik, Donald C.; Gangloff, Richard P.

    1991-01-01

    The environmental fatigue crack propagation behavior of advanced Al-Li-Cu based alloys and metal matrix composites is being characterized. Aqueous NaCl and water vapor, which produce atomic hydrogen by reactions on clean crack surfaces, are emphasized. The effects of environment sensitive crack closure, stress ratio, and precipitate microstructure are assessed. Mechanistic models are sought for intrinsic crack tip damage processes to enable predictions of cracking behavior outside of the data, metallurgical improvements in material cracking resistance, and insight on hydrogen compatibility.

  18. Effect of angleplying and matrix enhancement on impact-resistant boron/aluminum composites

    NASA Technical Reports Server (NTRS)

    Mcdanels, D. L.; Signorelli, R. A.

    1976-01-01

    Efforts to improve the impact resistance of B/Al are reviewed and analyzed. Tensile and dynamic modulus tests, thin sheet Charpy and Izod impact tests, and standard full size Charpy impact tests were conducted on 0.20 mm (8 mil) diameter-B/1100 Al matrix composites. Angleplies ranged from unidirectional to + or - 30 deg. The best compromise between reduced longitudinal properties and increased transverse properties was obtained with + or - 15 deg angleply. The pendulum impact strengths of improved B/Al were higher than that of notched titanium and appear to be enough to warrant consideration of B/Cl for application to fan blades in aircraft gas turbine engines.

  19. Heat treatment optimization of alumina/aluminum metal matrix composites using the Taguchi approach

    SciTech Connect

    Saigal, A.; Leisk, G. )

    1992-03-01

    The paper describes the use of the Taguchi approach for optimizing the heat treatment process of alumina-reinforced Al-6061 metal-matrix composites (MMCs). It is shown that the use of the Taguchi method makes it possible to test a great number of factors simultaneously and to provide a statistical data base that can be used for sensitivity and optimization studies. The results of plotting S/N values versus vol pct, solutionizing time, aging time, and aging temperature showed that the solutionizing time and the aging temperature significantly affect both the yield and the ultimate tensile strength of alumina/Al MMCs. 11 refs.

  20. Structural Damage Prediction and Analysis for Hypervelocity Impact: Properties of Largest Fragment Produced by Hypervelocity Impact of Aluminum Spheres with Thin Aluminum Sheets

    NASA Technical Reports Server (NTRS)

    Piekutowski, Andrew J.

    1995-01-01

    Results of a series of hypervelocity impact tests are presented. In these tests, 1.275-g, 9.53-mm-diameter, 2017-T4 aluminum spheres were fired at normal incidence at eight thicknesses of 6061-T6 aluminum sheet. Bumper thickness to projectile diameter (t/D) ratio ranged from 0.026 to 0.424. Nominal impact velocity was 6.7 km/s. Results of five tests using 6.35, 9.53, and 12.70-mm-diameter aluminum spheres and other aluminum alloy bumpers are also given. A large chunky fragment of projectile was observed at the center of the debris clouds produced by the impacts. The equivalent diameter of this large fragment ranged from 5.5 mm for the lowest t/D ratio to a minimum of 0.6 mm for the case where maximum breakup of the projectile occurred (t/D approximately 0.2 to 0.3). When the t/D ratio was 0.42, numerous large flaky fragments were evenly distributed in the external bubble of bumper debris. Velocity of the large central fragments decreased continuously with increasing t/D ratio, ranging from about 99 percent to less than 80 percent of the impact velocity. The change in the velocity of small fragments spalling from the rear of the projectile was used to obtain a relationship showing a linear increase in the size of the central projectile fragment with decrease in the shock-induced stress in the projectile.

  1. The Development of 6061-Aluminum Windows for the MICE LiquidAbsorber

    SciTech Connect

    Lau, W.; Yang, S.Q.; Green, M.A.; Ishimoto, S.; Swanson, J.

    2005-08-24

    The thin windows for the Muon Ionization Cooling Experiment (MICE) liquid Absorber will be fabricated from 6061-T6-aluminum. The absorber and vacuum vessel thin windows are 300-mm in diameter and are 180 mm thick at the center. The windows are designed for an internal burst pressure of 0.68 MPa (100 psig) when warm. The MICE experiment design calls for changeable windows on the absorber, so a bolted window design was adopted. Welded windows offer some potential advantages over bolted windows when they are on the absorber itself. This report describes the bolted window and its seal. This report also describes an alternate window that is welded directly to the absorber body. The welded window design presented permits the weld to be ground off and re-welded. This report presents a thermal FEA analysis of the window seal-weld, while the window is being welded. Finally, the results of a test of a welded-window are presented.

  2. Investigation of surface topography effects on metal flow under lubricated hot compression of aluminum

    NASA Astrophysics Data System (ADS)

    Kurk, Justin Irvin

    An investigation was conducted to study the effects of die surface topography, specifically surface roughness and lay, on metal flow and the friction factor under lubricated hot compression. 6061-T6 aluminum rings and square bar stock specimens were compressed on H-13 tool steel platens machined with a unidirectional lay pattern to six different roughnesses between a R 0 10 and 240 muin. A lab based hydraulic press mounted with an experimental die set was used for all testing. Repeated trials were conducted using high temperature vegetable oil and boron nitride lubricants. Metal flow was quantified as a function of surface roughness, lay orientation, and die temperature. Approximate plane strain cigar test specimens were compressed at platen temperatures of 300 °F and 400 °F and at orientations of 0°, 45°, and 90° between the longitudinal axis and unidirectional platen surface lay. The friction factor was assessed using the ring compression test under varying platen roughness conditions and die temperatures between 250 °F and 400 °F. Results indicate metal flow is optimized at low platen roughnesses and orientations parallel to the surface lay of the platen. Die temperature was not found to influence metal flow within the temperature range investigated. The friction factor was observed to be minimized at lower die temperatures and platen roughnesses.

  3. A chrome-free conversion coating and sealant for aluminum and its alloys

    SciTech Connect

    Bibber, J.W.

    1999-07-01

    For over fifty years, chromates have been the standard against which other conversion coatings and/or sealants have been judged. Due to current environmental and safety concerns, they are being removed from use. This paper presents neutral salt-spray, filiform primer adhesion and electrical conductivity data on a commercial chromate-free, inorganic and non-toxic conversion coating used with a new and unique sealing emulsion. The seal is an organic water based emulsion which when dried on a permanganate based conversion coated aluminum surface will be polymerized, or cured, when heated to 250--300 F for 20 seconds or longer. The higher the temperature, or period of time, the greater the degree of polymerization. The polymerized film is as electrically conductive as chromate films and easily accepts and bonds to applied primers. For in-service repair a conventional heat-gun maybe used. For large surfaces, any other conventional heat source may be used. The 6061-T6, 7075-T6, and 2024-T3 series wrought alloys were tested and directly compared to current chromate based conversion coatings. The tests showed equivalent or superior results in all cases.

  4. 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.

  5. Aluminum(III) selective potentiometric sensor based on morin in poly(vinyl chloride) matrix.

    PubMed

    Gupta, Vinod K; Jain, Ajay K; Maheshwari, Gaurav

    2007-06-15

    Al(3+) selective sensor has been fabricated from poly(vinyl chloride) (PVC) matrix membranes containing neutral carrier morin as ionophore. Best performance was exhibited by the membrane having composition as morin:PVC:sodium tetraphenyl borate:tri-n-butylphosphate in the ratio 5:150:5:150 (w/w, mg). This membrane worked well over a wide activity range of 5.0x10(-7) to 1.0x10(-1)M of Al(3+) with a Nernstian slope of 19.7+/-0.1mV/decade of Al(3+) activity and a limit of detection 3.2x10(-7)M. The response time of the sensor is approximately 5s and membrane could be used over a period of 2 months with good reproducibility. The proposed sensor works well over a pH range (3.5-5.0) and demonstrates good discriminating power over a number of mono-, di- and trivalent cations. The sensor can also be used in partially non-aqueous media having up to 20% (v/v) methanol, ethanol or acetone content with no significant change in the value of slope or working activity range. The sensor has also been used in the potentiometric titration of Al(3+) with EDTA and for its determination in zinc plating mud and red mud. PMID:19071785

  6. Penetration experiments in aluminum 1100 targets using soda-lime glass projectiles

    NASA Technical Reports Server (NTRS)

    Horz, Friedrich; Cintala, Mark J.; Bernhard, Ronald P.; Cardenas, Frank; Davidson, William E.; Haynes, Gerald; See, Thomas H.; Winkler, Jerry L.

    1995-01-01

    The cratering and penetration behavior of annealed aluminum 1100 targets, with thickness varied from several centimeters to ultra-thin foils less than 1 micrometer thick, were experimentally investigated using 3.2 mm diameter spherical soda-lime glass projectiles at velocities from 1 to 7 km/s. The objective was to establish quantitative, dimensional relationships between initial impact conditions (impact velocity, projectile diameter, and target thickness) and the diameter of the resulting crater or penetration hole. Such dimensional relationships and calibration experiments are needed to extract the diameters and fluxes of hypervelocity particles from space-exposed surfaces and to predict the performance of certain collisional shields. The cratering behavior of aluminum 1100 is fairly well predicted. However, crater depth is modestly deeper for our silicate impactors than the canonical value based on aluminum projectiles and aluminum 6061-T6 targets. The ballistic-limit thickness was also different. These differences attest to the great sensitivity of detailed crater geometry and penetration behavior on the physical properties of both the target and impactor. Each penetration experiment was equipped with a witness plate to monitor the nature of the debris plume emanating from the rear of the target. This plume consists of both projectile fragments and target debris. Both penetration hole and witness-plate spray patterns systematically evolve in response to projectile diameter/target thickness. The relative dimensions of the projectile and target totally dominate the experimental products documented in this report; impact velocity is an important contributor as well to the evolution of penetration holes, but is of subordinate significance for the witness-plate spray patterns.

  7. The Effect of Nanosized Pb Liquid Phase on the Damping Behavior in Aluminum Matrix Composite Based on the 2024Al-BaPbO3 System

    NASA Astrophysics Data System (ADS)

    Fan, G. H.; Geng, L.; Wu, H.; Zheng, Z. Z.; Meng, Q. C.

    2016-03-01

    An aluminum matrix composite containing nanosized Pb particles was fabricated by a powder metallurgy technique based on the 2024Al-BaPbO3 system. The composite exhibited a high and broad damping peak at the melting temperature range of nanosized Pb particles. The increase in value and breadth of the damping peak was attributed to the dislocation damping of the interfacial matrix close to the nanosized Pb liquid phase. The damping peak is expected to be enhanced by further refining the Pb particle size.

  8. Development of a job-exposure matrix for exposure to total and fine particulate matter in the aluminum industry

    PubMed Central

    Noth, Elizabeth M.; Dixon-Ernst, Christine; Liu, Sa; Cantley, Linda; Tessier-Sherman, Baylah; Eisen, Ellen A.; Cullen, Mark R.; Hammond, S. Katharine

    2014-01-01

    Increasing evidence indicates that exposure to particulate matter (PM) at environmental concentrations increases the risk of cardiovascular disease, particularly PM with an aerodynamic diameter of less than 2.5μm (PM2.5). Despite this, the health impacts of higher occupational exposures to PM2.5 have rarely been evaluated. In part, this research gap derives from the absence of information on PM2.5 exposures in the workplace. To address this gap, we have developed a job-exposure matrix (JEM) to estimate exposure to two size fractions of PM in the aluminum industry. Measurements of total PM (TPM) and PM2.5 were used to develop exposure metrics for an epidemiologic study. TPM exposures for distinct exposure groups (DEGs) in the JEM were calculated using 8,385 personal TPM samples collected at 11 facilities (1980-2011). For 8 of these facilities, simultaneous PM2.5 and TPM personal monitoring was conducted from 2010-2011 to determine the percent of TPM that is composed of PM2.5 (%PM2.5) in each DEG. The mean TPM from the JEM was then multiplied by %PM2.5 to calculate PM2.5 exposure concentrations in each DEG. Exposures in the smelters were substantially higher than in fabrication units; mean TPM concentrations in smelters and fabrication facilities were 3.86 mg/m3 and 0.76 mg/m3, and the corresponding mean PM2.5 concentrations were 2.03 mg/m3 and 0.40 mg/m3. Observed occupational exposures in this study generally exceeded environmental PM2.5 concentrations by an order of magnitude. PMID:24022670

  9. Fusion boundary microstructure evolution in aluminum alloys

    NASA Astrophysics Data System (ADS)

    Kostrivas, Anastasios Dimitrios

    2000-10-01

    A melting technique was developed to simulate the fusion boundary of aluminum alloys using the GleebleRTM thermal simulator. Using a steel sleeve to contain the aluminum, samples were heated to incremental temperatures above the solidus temperature of a number of alloys. In alloy 2195, a 4wt%Cu-1wt%Li alloy, an equiaxed non-dendritic zone (EQZ) could be formed by heating in the temperature range from approximately 630 to 640°C. At temperatures above 640°C, solidification occurred by the normal epitaxial nucleation and growth mechanism. Fusion boundary behavior was also studied in alloys 5454-H34, 6061-T6, and 2219-T8. Additionally, experimental alloy compositions were produced by making bead on plate welds using an alloy 5454-H32 base metal and 5025 or 5087 filler metals. These filler metals contain zirconium and scandium additions, respectively, and were expected to influence nucleation and growth behavior. Both as-welded and welded/heat treated (540°C and 300°C) substrates were tested by melting simulation, resulting in dendritic and EQZ structures depending on composition and substrate condition. Orientation imaging microscopy (OIM(TM)) was employed to study the crystallographic character of the microstructures produced and to verify the mechanism responsible for EQZ formation. OIM(TM) proved that grains within the EQZ have random orientation. In all other cases, where the simulated microstructures were dendritic in nature, it was shown that epitaxy was the dominant mode of nucleation. The lack of any preferred crystallographic orientation relationship in the EQZ supports a theory proposed by Lippold et al that the EQZ is the result of heterogeneous nucleation within the weld unmixed zone. EDS analysis of the 2195 on STEM revealed particles with ternary composition consisted of Zr, Cu and Al and a tetragonal type crystallographic lattice. Microdiffraction line scans on EQZ grains in the alloy 2195 showed very good agreement between the measured Cu

  10. Impact Welding of Aluminum to Copper and Stainless Steel by Vaporizing Foil Actuator: Effect of Heat Treatment Cycles on Mechanical Properties and Microstructure

    NASA Astrophysics Data System (ADS)

    Vivek, Anupam; Hansen, Steven; Benzing, Jake; He, Mei; Daehn, Glenn

    2015-10-01

    This work studies the mechanical property effect of microstructure on impact welds of aluminum alloy AA6061 with both copper alloy Cu 110 and stainless steel AISI 304. AA6061-T6 and T4 temper aluminum sheets of 1 mm thickness were launched toward copper and stainless steel targets using the vaporizing foil actuator technique. Flyer plate velocities, measured via photonic Doppler velocimetry, were observed to be approximately 800 m/s. The welded aluminum-copper samples were subjected to instrumented peel testing, microhardness testing, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. The welded joints exhibited cracks through their continuous intermetallic layers. The cracks were impeded upon encountering a ductile metallic wave. The welds created with T6 temper flyer sheets were found to have smaller intermetallic-free and wavy interface regions as compared to those created with T4 temper flyer sheets. Peel strength tests of the two weld combinations resulted in failure along the interface in the case of the T6 flyer welds, while the failure generally occurred in the parent aluminum for the T4 temper flyer welds. Half of the T4 flyer welds were subjected to aging for 18 h at 433 K (160 °C) to convert the aluminum sheet to the T6 condition. Although the aged flyer material did not attain the hardness of the as-received T6 material, it was found to be significantly stronger than the T4 material. These welds retained their strength after the aging process, and diffusion across the interface was minimal. The welded aluminum-stainless steel samples were analyzed on a more basic level than aluminum-copper samples, but were found to exhibit similar results.

  11. Processing and properties of TiNi shape memory fiber-reinforced 6061 aluminum matrix composite made by spark plasma sintering

    NASA Astrophysics Data System (ADS)

    Mizuuchi, Kiyoshi; Inoue, Kanryu; Hamada, K.; Sugioka, M.; Itami, M.; Okanda, Y.; Kawahara, M.

    2000-08-01

    Aluminum alloy matrix composite reinforced by continuous TiNi shape memory allow (SMA) fiber was fabricated by Spark Plasma Sintering (SPS) process of A1 alloy powder with 20 vol. % of the TiNi SMA fiber, and its microstructure and mechanical properties were examined. The A1 alloy powder with the TiNi fiber was readily consolidated into composite at temperatures between 633K and 873K. The relative packing density of the composite fabricated increased with increasing sintering temperature. Reaction occurred at the boundary between A1 alloy matrix and TiNi fiber and the interfacial reaction is considered to consist of three intermetallic phases, Ni3Ti (next to TiNI), Ni2Ti and Al3Ni (next to A1 matrix). The tensile yield stress of the composite deformed in tension at 373K was higher by about 40MPa than at 293K.

  12. X-ray and neutron diffraction measurements of dislocation density and subgrain size in a friction stir welded aluminum alloy

    SciTech Connect

    Claussen, Bjorn; Woo, Wanchuck; Zhili, Feng; Edward, Kenik; Ungar, Tamas

    2009-01-01

    The dislocation density and subgrain size were determined in the base material and friction-stir welds of 6061-T6 aluminum alloy. High-resolution X-ray diffraction measurement was performed in the base material. The result of the line profile analysis of the X-ray diffraction peak shows that the dislocation density is about 4.5 x 10{sup 14} m{sup 02} and the subgrain size is about 200 nm. Meanwhile, neutron diffraction measurements have been performed to observe the diffraction peaks during friction-stir welding (FSW). The deep penetration capability of the neutron enables us to measure the peaks from the midplane of the Al plate underneath the tool shoulder of the friction-stir welds. The peak broadening analysis result using the Williamson-Hall method shows the dislocation density of about 3.2 x 10{sup 15} m{sup -2} and subgrain size of about 160 nm. The significant increase of the dislocation density is likely due to the severe plastic deformation during FSW. This study provides an insight into understanding the transient behavior of the microstructure under severe thermomechanical deformation.

  13. Salt Spray Test to Determine Galvanic Corrosion Levels of Electroless Nickel Connectors Mounted on an Aluminum Bracket

    NASA Technical Reports Server (NTRS)

    Rolin, T. D.; Hodge, R. E.; Torres, P. D.; Jones, D. D.; Laird, K. R.

    2014-01-01

    During preliminary vehicle design reviews, requests were made to change flight termination systems from an electroless nickel (EN) connector coating to a zinc-nickel (ZN) plating. The reason for these changes was due to a new NASA-STD-6012 corrosion requirement where connectors must meet the performance requirement of 168 hr of exposure to salt spray. The specification for class F connectors, MIL-DTL-38999, certifies the EN coating will meet a 48-hr salt spray test, whereas the ZN is certified to meet a 168-hr salt spray test. The ZN finish is a concern because Marshall Space Flight Center has no flight experience with ZN-finished connectors, and MSFC-STD-3012 indicates that zinc and zinc alloys should not be used. The purpose of this test was to run a 168-hr salt spray test to verify the electrical and mechanical integrity of the EN connectors and officially document the results. The salt spray test was conducted per ASTM B117 on several MIL-DTL-38999 flight-like connectors mounted to an aluminum 6061-T6 bracket that was alodined. The configuration, mounting techniques, electrical checks, and materials used were typical of flight and ground support equipment.

  14. Conical shaped charge pressed powder, metal liner jet characterization and penetration in aluminum

    SciTech Connect

    Vigil, M.G.

    1997-05-01

    This work was conducted as part of a Near-wellbore Mechanics program at Sandia National Laboratories. An understanding of the interaction of the perforator jet from an explosive shaped charge with the fluid filled porous sandstone media is of basic importance to the completion of oil wells. Tests were conducted using the five-head Flash X-ray Test Site to measure the jet tip velocities and jet geometry for the OMNI and CAPSULE Conical Shaped Charge (CSC) oil well perforator jets fired into air. These tests were conducted to generate jet velocity and geometry information to be used in validating the CTH hydrocode modeling/simulation development of pressed powder, metal liner jets in air. Ten tests were conducted to determine the CSC jet penetration into 6061-T6 aluminum targets. Five tests were conducted with the OMNI CSC at 0.25, 6.0, and 19 inch standoffs from the target. Five tests were conducted with the CAPSULE CSC at 0.60, 5.0, 10.0, and 19 inch standoffs from the target. These tests were conducted to generate jet penetration into homogeneous target information for use in validating the CTH code modeling/simulation of pressed powder, metal liner jets penetrating aluminum targets. The Flash X-ray radiographs, jet velocities, jet diameters, and jet lengths data for jets fired into air are presented in this report. The jet penetration into aluminum and penetration hole profile data are also presented for the OMNI and CAPSULE perforators. Least Squares fits are presented for the measured jet velocity and jet penetration data.

  15. Matrix grain characterisation by electron backscattering diffraction of powder metallurgy aluminum matrix composites reinforced with MoSi{sub 2} intermetallic particles

    SciTech Connect

    Corrochano, J. Hidalgo, P.; Lieblich, M.; Ibanez, J.

    2010-11-15

    Research highlights: Six extruded PM AA6061/MoSi{sub 2}/15p were processed with and without ball milling {yields} EBSD was used to characterise matrix grain size and grain orientation. {yields} Ball milling decreases matrix grain size to submicrometric level. {yields} Ball milling produces a more equiaxed microstructure and larger misorientation. {yields} Increasing milling time produces matrix texture randomization.

  16. Effects of MgO Nano Particles on Microstructural and Mechanical Properties of Aluminum Matrix Composite prepared via Powder Metallurgy Route

    NASA Astrophysics Data System (ADS)

    Baghchesara, Mohammad Amin; Abdizadeh, Hossein; Baharvandi, Hamid Reza

    The objective of the present investigation was to evaluate the microstructural and mechanical properties of Al/nano MgO composite prepared via powder metallurgy method. Pure atomized aluminum powder with an average particle size of 1μm and MgO particulate with an average particle size between 60 to 80 nm were used. Composites containing 1.5, 2.5 and 5 percent of volume fraction of MgO were prepared by powder metallurgy method. The specimens were pressed by Cold Isostatic Press machine (CIP), subsequently were sintered at 575, 600 and 625°C. After sintering and preparing the samples, mechanical properties were measured. The results of microstructure, compression and hardness tests indicated that addition of MgO particulates to aluminum matrix composites improves the mechanical properties.

  17. Tensile deformation and fracture behavior of spray-deposition 7075/15SiC{sub p} aluminum matrix composite sheet at elevated temperatures

    SciTech Connect

    Zhang Hui He Yusong; Li Luoxing

    2008-08-15

    The tensile deformation and fracture behavior of spray-deposition 7075/15SiC{sub p} (15 vol.% SiC particle) aluminum matrix composite sheet were studied by uniaxial tension tests at temperatures ranging from 300 deg. C to 450 deg. C and strain rates of 0.001-0.1 s{sup -1}, and the fracture surfaces were examined by using a scanning electron microscopy. The results show that strain softening is present up to the point of failure and the flow stress level increases with increasing strain rate but decreases with increasing temperature. The total elongation to fracture increases with increasing temperature and with decreasing strain rate. The maximum strain rate sensitivity exponent is 0.24 which is much lower than that of typical superplastic materials. The apparent activation energy is calculated to be approximately 379 kJ/mol which is much higher than its unreinforced counterpart. The fracture surface morphology shows a large amount of localized plastic deformation in the aluminum matrix and numerous large cavities around the reinforcement. The absence of strain accommodation by interface sliding might have caused premature failure at the reinforcement/matrix interface.

  18. Spark Plasma Sintering of Aluminum-Magnesium-Matrix Composites with Boron Carbide and Tungsten Nano-powder Inclusions: Modeling and Experimentation

    NASA Astrophysics Data System (ADS)

    Dvilis, E. S.; Khasanov, O. L.; Gulbin, V. N.; Petyukevich, M. S.; Khasanov, A. O.; Olevsky, E. A.

    2016-03-01

    Spark-plasma sintering (SPS) is used to fabricate fully-dense metal-matrix (Al/Mg) composites containing hard ceramic (boron carbide) and refractory metal (tungsten) inclusions. The study objectives include the modeling (and its experimental verification) of the process of the consolidation of the composites consisted of aluminum-magnesium alloy AMg6 (65 wt.%), B4C powder (15 wt.%), and W nano-powder (20 wt.%), as well as the optimization of the composite content and of the SPS conditions to achieve higher density. Discrete element modeling of the composite particles packing based on the particle size distribution functions of real powders is utilized for the determination of the powder compositions rendering maximum mixture packing densities. Two models: a power-law creep model of the high temperature deformation of powder materials, and an empirical logarithmic pressure-temperature-relative density relationship are successfully applied for the description of the densification of the aluminum-magnesium metal matrix powder composite subjected to spark-plasma sintering. The elastoplastic properties of the sintered composite samples are assessed by nanoindentation.

  19. Tensile and Dry Sliding Wear Behavior of In-Situ Al3Zr + Al2O3-Reinforced Aluminum Metal Matrix Composites

    NASA Astrophysics Data System (ADS)

    Gautam, G.; Ghose, A. K.; Chakrabarty, I.

    2015-12-01

    In the present study, aluminum-based in-situ intermetallic Al3Zr and Al2O3-reinforced metal matrix composites have been synthesized by direct melt reaction through stir casting of zirconium oxychloride (ZrOCl2·8H2O) powder in commercially pure aluminum. The in-situ reaction produces intermetallic Al3Zr needles that change to feathery morphology with increasing ZrOCl2·8H2O, while the Al2O3 is of fine globular shape. The tensile strengths of these composites increase with increasing volume percent reinforcements, attaining a peak value with 18 pct addition. The dry sliding wear behavior of the composites was evaluated with varying parameters, viz. sliding distance, normal load, and sliding velocities. The wear mechanisms are explained based on the microstructure, the topography of the worn surface, and the interfacial strength of the matrix and reinforcement. The tensile and wear properties are compared with widely used wear resistant hypereutectic Al-17 pct Si cast alloy.

  20. Duplex Al2O3/DLC Coating on 15SiCp/2024 Aluminum Matrix Composite Using Combined Microarc Oxidation and Filtered Cathodic Vacuum Arc Deposition

    NASA Astrophysics Data System (ADS)

    Xue, Wenbin; Tian, Hua; Du, Jiancheng; Hua, Ming; Zhang, Xu; Li, Yongliang

    2012-08-01

    Microarc oxidation (MAO) treatment produces a thick Al2O3 coating on the 15SiCp/2024 aluminum matrix composite. After pretreatment of Ti ion implantation, a thin diamond-like carbon film (DLC) was deposited on the top of polished Al2O3 coating by a pulsed filtered cathodic vacuum arc (FCVA) deposition system with a metal vapor vacuum arc (MEVVA) source. The morphology and tribological properties of the duplex Al2O3/DLC multiplayer coating were investigated by Raman spectroscopy, scanning electron microscopy (SEM) and SRV ball-on-disk friction tester. It is found that the duplex Al2O3/DLC coating had good adhesion and a low friction coefficient of less than 0.07. As compared to a single Al2O3 or DLC coating, the duplex Al2O3/DLC coating on aluminum matrix composite exhibited a better wear resistance against ZrO2 ball under dry sliding, because the Al2O3 coating as an intermediate layer improved load support for the top DLC coating on 15SiCp/2024 composite substrate, meanwhile the top DLC coating displayed low friction coefficient.

  1. X-Ray and Neutron Diffraction Measurements of Dislocation Density and Subgrain Size in a Friction-Stir-Welded Aluminum Alloy

    SciTech Connect

    Woo, Wan Chuck; Ungar, Prof Tomas; Feng, Zhili; Kenik, Edward A; Clausen, B

    2009-01-01

    The dislocation density and subgrain size were determined in the base material and friction-stir welds of 6061-T6 aluminum alloy. High-resolution X-ray diffraction measurement was performed in the base material. The result of the line profile analysis of the X-ray diffraction peak shows that the dislocation density is about 4.5 x 10{sup 14} m{sup -2} and the subgrain size is about 200 nm. Meanwhile, neutron diffraction measurements have been performed to observe the diffraction peaks during friction-stir welding (FSW). The deep penetration capability of the neutron enables us to measure the peaks from the midplane of the Al plate underneath the tool shoulder of the friction-stir welds. The peak broadening analysis result using the Williamson-Hall method shows the dislocation density of about 3.2 x 10{sup 15} m{sup -2} and subgrain size of about 160 nm. The significant increase of the dislocation density is likely due to the severe plastic deformation during FSW. This study provides an insight into understanding the transient behavior of the microstructure under severe thermomechanical deformation.

  2. X-Ray and Neutron Diffraction Measurements of Dislocation Density and Subgrain Size in a Friction-Stir-Welded Aluminum Alloy

    NASA Astrophysics Data System (ADS)

    Woo, Wanchuck; Ungár, Tamás; Feng, Zhili; Kenik, Edward; Clausen, Bjørn

    2010-05-01

    The dislocation density and subgrain size were determined in the base material and friction-stir welds of 6061-T6 aluminum alloy. High-resolution X-ray diffraction measurement was performed in the base material. The result of the line profile analysis of the X-ray diffraction peak shows that the dislocation density is about 4.5 × 1014 m-2 and the subgrain size is about 200 nm. Meanwhile, neutron diffraction measurements have been performed to observe the diffraction peaks during friction-stir welding (FSW). The deep penetration capability of the neutron enables us to measure the peaks from the midplane of the Al plate underneath the tool shoulder of the friction-stir welds. The peak broadening analysis result using the Williamson-Hall method shows the dislocation density of about 3.2 × 1015 m-2 and subgrain size of about 160 nm. The significant increase of the dislocation density is likely due to the severe plastic deformation during FSW. This study provides an insight into understanding the transient behavior of the microstructure under severe thermomechanical deformation.

  3. Optimization of magnetically accelerated, ultra-high velocity aluminum flyer plates for use in plate impact, shock wave experiments.

    SciTech Connect

    Cochrane, Kyle Robert; Knudson, Marcus D.; Slutz, Stephen A.; Lemke, Raymond William; Davis, J. P.; Harjes, Henry Charles III; Giunta, Anthony Andrew; Bliss, David Emery

    2005-05-01

    The intense magnetic field produced by the 20 MA Z accelerator is used as an impulsive pressure source to accelerate metal flyer plates to high velocity for the purpose of performing plate impact, shock wave experiments. This capability has been significantly enhanced by the recently developed pulse shaping capability of Z, which enables tailoring the rise time to peak current for a specific material and drive pressure to avoid shock formation within the flyer plate during acceleration. Consequently, full advantage can be taken of the available current to achieve the maximum possible magnetic drive pressure. In this way, peak magnetic drive pressures up to 490 GPa have been produced, which shocklessly accelerated 850 {micro}m aluminum (6061-T6) flyer plates to peak velocities of 34 km/s. We discuss magnetohydrodynamic (MHD) simulations that are used to optimize the magnetic pressure for a given flyer load and to determine the shape of the current rise time that precludes shock formation within the flyer during acceleration to peak velocity. In addition, we present results pertaining to plate impact, shock wave experiments in which the aluminum flyer plates were magnetically accelerated across a vacuum gap and impacted z-cut, {alpha}-quartz targets. Accurate measurements of resulting quartz shock velocities are presented and analyzed through high-fidelity MHD simulations enhanced using optimization techniques. Results show that a fraction of the flyer remains at solid density at impact, that the fraction of material at solid density decreases with increasing magnetic pressure, and that the observed abrupt decrease in the quartz shock velocity is well correlated with the melt transition in the aluminum flyer.

  4. Microwave combustion synthesis of in situ Al{sub 2}O{sub 3} and Al{sub 3}Zr reinforced aluminum matrix composites

    SciTech Connect

    Zhu, Heguo; Hua, Bo; Cui, Tao; Huang, Jiewen; Li, Jianliang; Xie, Zonghan

    2015-08-15

    Al{sub 2}O{sub 3} and Al{sub 3}Zr reinforced aluminum matrix composites were fabricated from Al and ZrO{sub 2} powders by SiC assisted microwave combustion synthesis. The microstructure and reaction pathways were analyzed by using differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). The results showed that the heating rate during microwave synthesis was very high and the entire process took several minutes and that the ignition temperature of the reaction was much lower than that of conventional methods. In addition, the resulting microstructure was found to be finer than that prepared by the conventional methods and no cracks can be seen in the Al{sub 3}Zr reinforcements. As such, the newly developed composites have potential for safety-critical applications where catastrophic failure is not tolerated.

  5. Coating of 6028 Aluminum Alloy Using Aluminum Piston Alloy and Al-Si Alloy-Based Nanocomposites Produced by the Addition of Al-Ti5-B1 to the Matrix Melt

    NASA Astrophysics Data System (ADS)

    El-Labban, Hashem F.; Abdelaziz, M.; Mahmoud, Essam R. I.

    2014-10-01

    The Al-12 pctSi alloy and aluminum-based composites reinforced with TiB2 and Al3Ti intermetallics exhibit good wear resistance, strength-to-weight ratio, and strength-to-cost ratio when compared to equivalent other commercial Al alloys, which make them good candidates as coating materials. In this study, structural AA 6028 alloy is used as the base material. Four different coating materials were used. The first one is Al-Si alloy that has Si content near eutectic composition. The second, third, and fourth ones are Al-6 pctSi-based reinforced with TiB2 and Al3Ti nano-particles produced by addition of Al-Ti5-B1 master alloy with different weight percentages (1, 2, and 3 pct). The coating treatment was carried out with the aid of GTAW process. The microstructures of the base and coated materials were investigated using optical microscope and scanning electron microscope equipped with EDX analyzer. Microhardness of the base material and the coated layer were evaluated using a microhardness tester. GTAW process results in almost sound coated layer on 6028 aluminum alloy with the used four coating materials. The coating materials of Al-12 pct Si alloy resulted in very fine dendritic Al-Si eutectic structure. The interface between the coated layer and the base metal was very clean. The coated layer was almost free from porosities or other defects. The coating materials of Al-6 pct Si-based mixed with Al-Ti5-B1 master alloy with different percentages (1, 2, and 3 pct), results in coated layer consisted of matrix of fine dendrite eutectic morphology structure inside α-Al grains. Many fine in situ TiAl3 and TiB2 intermetallics were precipitated almost at the grain boundary of α-Al grains. The amounts of these precipitates are increased by increasing the addition of Al-Ti5-B1 master alloy. The surface hardness of the 6028 aluminum alloy base metal was improved with the entire four used surface coating materials. The improvement reached to about 85 pct by the first type of

  6. A theoretical approach to the photochemical activation of matrix isolated aluminum atoms and their reaction with methane.

    PubMed

    Pacheco-Blas, M A; Novaro, O A; Pacheco-Sánchez, J H

    2010-11-01

    The photochemical activation of Al atoms in cryogenic matrices to induce their reaction with methane has been experimentally studied before. Here, a theoretical study of the nonadiabatic transition probabilities for the ground ((2)P:3s(2)3p(1)) and the lowest excited states ((2)S:3s(2)4s(1) and (2)D:3s(2)3d(1)) of an aluminum atom interacting with a methane molecule (CH(4)) was carried out through ab initio Hartree-Fock self-consistent field calculations. This was followed by a multiconfigurational study of the correlation energy obtained by extensive variational and perturbational configuration interaction analyses using the CIPSI program. The (2)D state is readily inserted into a C-H bond, this being a prelude to a sequence of avoided crossings with the initially repulsive (to CH(4)) lower lying states (2)P and (2)S. We then use a direct extension of the Landau-Zener theory to obtain transition probabilities at each avoided crossing, allowing the formation of an HAlCH(3) intermediate that eventually leads to the final pair of products H+AlCH(3) and HAl+CH(3). PMID:21054032

  7. A theoretical approach to the photochemical activation of matrix isolated aluminum atoms and their reaction with methane

    SciTech Connect

    Pacheco-Blas, M. A.; Novaro, O. A.; Pacheco-Sanchez, J. H.

    2010-11-07

    The photochemical activation of Al atoms in cryogenic matrices to induce their reaction with methane has been experimentally studied before. Here, a theoretical study of the nonadiabatic transition probabilities for the ground ({sup 2}P:3s{sup 2}3p{sup 1}) and the lowest excited states ({sup 2}S:3s{sup 2}4s{sup 1} and {sup 2}D:3s{sup 2}3d{sup 1}) of an aluminum atom interacting with a methane molecule (CH{sub 4}) was carried out through ab initio Hartree-Fock self-consistent field calculations. This was followed by a multiconfigurational study of the correlation energy obtained by extensive variational and perturbational configuration interaction analyses using the CIPSI program. The {sup 2}D state is readily inserted into a C-H bond, this being a prelude to a sequence of avoided crossings with the initially repulsive (to CH{sub 4}) lower lying states {sup 2}P and {sup 2}S. We then use a direct extension of the Landau-Zener theory to obtain transition probabilities at each avoided crossing, allowing the formation of an HAlCH{sub 3} intermediate that eventually leads to the final pair of products H+AlCH{sub 3} and HAl+CH{sub 3}.

  8. Construction of a Job Exposure Matrix to Dust, Fluoride, and Polycyclic Aromatic Hydrocarbons in the Norwegian Aluminum Industry using Prediction Models

    PubMed Central

    Søyseth, Vidar; Henneberger, Paul; Virji, Mohammed Abbas; Bakke, Berit; Kongerud, Johny

    2016-01-01

    Background The Norwegian aluminum industry developed and implemented a protocol for prospective monitoring of employees’ exposure using personal samplers. We analyzed these data to develop prediction lines to construct a job exposure matrix (JEM) for the period 1986–1995. Methods The protocol for personal monitoring of exposure was implemented in all seven Norwegian aluminum plants in 1986 and continued until 1995. Personal samplers were used to collect total dust, fluorides, and total polycyclic aromatic hydrocarbons (PAH). In addition, exposure could be categorized according to process, i.e. prebake, Søderberg, and ‘other’. We constructed four-dimensional JEMs characterized by: Plant, Job descriptor, Process, and Year. Totally 8074, 6734, and 3524 measurements were available for dust, fluorides, and PAH, respectively. The data were analyzed using linear mixed models with two-way interactions. The models were assessed using the Akaike criterion (AIC) and unadjusted R2. The significance level was set to 10% (two-sided) for retaining variables in the model. Results In 1986, the geometric mean (95% confidence interval in parentheses) for total dust, total fluorides, and PAH were 3.18 (0.46–22.2) mg m−3, 0.58 (0.085–4.00) mg m−3, and 33.9 (2.3–504) μg m−3, respectively. During 10 years of follow-up, the exposure to total dust, fluorides, and PAH decreased by 9.2, 11.7, and 14.9% per year, respectively. Each model encompassed from 49 to 72 significant components of the interaction terms. The interaction components were at least as important as the main effects, and 65 to 91% of the significant components of the interaction terms were time-dependent. Conclusion Our prediction models indicated that exposures were highly time-dependent. We expect that the time-dependent changes in exposure are of major importance for longitudinal studies of health effects in the aluminum industry. PMID:26409268

  9. Inter-wall bridging induced peeling of multi-walled carbon nanotubes during tensile failure in aluminum matrix composites.

    PubMed

    Chen, Biao; Li, Shufeng; Imai, Hisashi; Umeda, Junko; Takahashi, Makoto; Kondoh, Katsuyoshi

    2015-02-01

    In situ scanning electron microscopy (SEM) observation of a tensile test was performed to investigate the fracturing behavior of multi-walled carbon nanotubes (MWCNTs) in powder metallurgy Al matrix composites. A multiple peeling phenomenon during MWCNT fracturing was clearly observed. Its formation mechanism and resultant effect on the composite strength were examined. Through transition electron microscopy characterizations, it was observed that defective structures like inter-wall bridges cross-linked adjacent walls of MWCNTs. This structure was helpful to improve the inter-wall bonding conditions, leading to the effective load transfer between walls and resultant peeling behaviors of MWCNTs. These results might provide new understandings of the fracturing mechanisms of carbon nanotube reinforcements for designing high-performance nanocomposites. PMID:25437849

  10. Improvement of Mechanical Properties in the Functionally Graded Aluminum Matrix Nanocomposites Fabricated via a Novel Multistep Friction Stir Processing

    NASA Astrophysics Data System (ADS)

    Salehi, Mojtaba; Farnoush, Hamidreza; Heydarian, Arash; Aghazadeh Mohandesi, Jamshid

    2015-02-01

    In the present study, the functionally graded bulk Al-SiC nanocomposites were successfully fabricated by applying a novel multistep friction stir processing. Microstructural observations by scanning electron microscope indicated a proper distribution of SiC nanoparticles in the Al 6061 matrix. Microhardness profiles descended to 50 from 160 Hv due to the formation of compositionally gradient of SiC nanoparticles along the thickness. The tensile behavior of graded samples revealed a simultaneous enhancement of ultimate tensile strength (44 pct), strain at maximum stress (244 pct), and work of fracture (492 pct) with respect to the homogeneous sample. Furthermore, the graded samples sustained up to 4 pct strain after initiation of primary cracking, while the catastrophic fracture occurred instantly after cracking in the homogenous sample. A dimple-like ductile fracture surface was observed for the graded layers in which an increase in the SiC particle content will result in smaller dimple size.

  11. Improvement of Mechanical Properties in the Functionally Graded Aluminum Matrix Nanocomposites Fabricated via a Novel Multistep Friction Stir Processing

    NASA Astrophysics Data System (ADS)

    Salehi, Mojtaba; Farnoush, Hamidreza; Heydarian, Arash; Aghazadeh Mohandesi, Jamshid

    2014-09-01

    In the present study, the functionally graded bulk Al-SiC nanocomposites were successfully fabricated by applying a novel multistep friction stir processing. Microstructural observations by scanning electron microscope indicated a proper distribution of SiC nanoparticles in the Al 6061 matrix. Microhardness profiles descended to 50 from 160 Hv due to the formation of compositionally gradient of SiC nanoparticles along the thickness. The tensile behavior of graded samples revealed a simultaneous enhancement of ultimate tensile strength (44 pct), strain at maximum stress (244 pct), and work of fracture (492 pct) with respect to the homogeneous sample. Furthermore, the graded samples sustained up to 4 pct strain after initiation of primary cracking, while the catastrophic fracture occurred instantly after cracking in the homogenous sample. A dimple-like ductile fracture surface was observed for the graded layers in which an increase in the SiC particle content will result in smaller dimple size.

  12. Modeling the Break-up of Nano-particle Clusters in Aluminum- and Magnesium-Based Metal Matrix Nano-composites

    NASA Astrophysics Data System (ADS)

    Manoylov, Anton; Bojarevics, Valdis; Pericleous, Koulis

    2015-07-01

    Aluminum- and magnesium-based metal matrix nano-composites with ceramic nano-reinforcements promise low weight with high durability and superior strength, desirable properties in aerospace, automobile, and other applications. However, nano-particle agglomerations lead to adverse effects on final properties: large-size clusters no longer act as dislocation anchors, but instead become defects; the resulting particle distribution will be uneven, leading to inconsistent properties. To prevent agglomeration and to break-up clusters, ultrasonic processing is used via an immersed sonotrode, or alternatively via electromagnetic vibration. A study of the interaction forces holding the nano-particles together shows that the choice of adhesion model significantly affects estimates of break-up force and that simple Stokes drag due to stirring is insufficient to break-up the clusters. The complex interaction of flow and co-joint particles under a high frequency external field (ultrasonic, electromagnetic) is addressed in detail using a discrete-element method code to demonstrate the effect of these fields on de-agglomeration.

  13. Control of interfacial reactions during liquid phase processing of aluminum matrix composites reinforced with INCONEL 601 fibers

    NASA Astrophysics Data System (ADS)

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

    1998-06-01

    A comprehensive investigation is made of the parameters affecting the extent of interface reactions during squeeze casting of composites consisting of a matrix of either pure Al or alloy AS13 reinforced with fibers of INCONEL 601. The process parameters are the preform thickness and temperature, the fiber volume fraction, the temperature and mass of the liquid metal, and the temperature of the die. Adjustment of these process parameters made possible the full control of reactions. It is found that reactions proceed mainly in the solid state after decomposition of the oxide barrier layer covering the fibers. A simple kinetic model is developed that enlightens the role of this barrier layer. No trace of reaction could be detected in composites processed using preoxidized preforms. Alloying Al with Si also induces a drastic reduction of reactivity. The high ductility of the composites attests to the processing quality. An original procedure is proposed for measuring the activation energy for initiation of reactions by differential thermal analysis.

  14. A correlation between salt spray and electrochemical impedance spectroscopy test results for conversion-coated aluminum alloys

    SciTech Connect

    Buchheit, R.G.; Cunningham, M.; Jensen, H.; Kendig, M.W.; Martinez, M.A.

    1998-01-01

    The corrosion resistance of 33 inorganic conversion coatings applied to five aluminum alloys was tested by salt spray exposure and electrochemical impedance spectroscopy (EIS). Results were evaluated to determine if a relationship existed. Individual salt spray test panels, with an area of 30 in.{sup 2} (194 cm{sup 2}), were inspected visually at regular intervals up to 168 h of exposure. At each inspection interval, panels were assigned a pass rank if <5 pits were observed, or a fail rank if >5 pits were observed. EIS data were analyzed using a simple equivalent circuit which yielded a coating resistance (R{sub c}), which was used as a figure of merit to assess coating performance. Examination of the data showed both tests could be sensitive discriminators of corrosion protection, but that EIS was more discriminating in the extremes of coating performance. Analysis showed the probability of achieving a passing salt spray result increased as R{sub c} increased. In the regimes where both tests were sensitive, regression analysis showed a linear relationship existed for each alloy substrate between the log of R{sub c} and the probability of a coating meeting the pass/fail criterion in salt spray. Based upon these relationships, threshold R{sub c} values were proposed to define the minimum value for which a given coating can be expected to attain a passing result in a 168-h salt spray test. These values were 2 {times} 10{sup 6} {Omega}-cm{sup 2} to 5 {times} 10{sup 6} {Omega}-cm{sup 2} for Al 356 (UNS A13560), Al 2024-T3 (UNS A92024), and Al 6061-T6 (UNS A96061); 1.5 {times} 10{sup 7} for Al 7075-T6 (UNS A97075); and 2.3 {times} 10{sup 6} {Omega}-cm{sup 2} for Al 3003 (UNS A93003).

  15. Investigation of the structure/property relationship of spray-formed 7XXX series high-strength aluminum alloys and their metal matrix composites

    NASA Astrophysics Data System (ADS)

    Sharma-Judd, Malavika M.

    2000-12-01

    The purpose of this investigation was to identify the structure/property relationship of spray formed 7XXX series alloys. High solute, ultra-high strength 7XXX series aluminum alloys with solute contents close to equilibrium solid solubility limits of the Al-Zn-Mg-Cu system have been produced by rapid solidification using spray deposition. The process yields massive preforms directly from the liquid state. Various elements, including chromium, manganese, silver, zirconium and scandium, were incorporated to produce a variety of microstructures and mechanical properties. SiC particulate was added to these same alloy compositions to produce metal matrix composites (MMCs). The resulting extruded products in the T6 and T7 conditions were evaluated and compared. Under peak-aged conditions in the unreinforced materials, strengths in excess of 860 MPa were achieved, with one alloy exceeding 900 MPa. Apart from the elongation to failure, the mechanical properties of the composite materials were equal to or superior to those of their unreinforced counterparts. The superior strength properties of the spray formed alloys were attributed to two major substructures with different scale; nanometer sized eta ' metastable precipitates and slightly larger, but finely distributed dispersoids. The large volume fraction of plate-like eta' precipitates (average size 58A, ranging up to 73 A in diameter) were identified as having a hexagonal structure with lattice parameters a = 0.488 nm and c = 1.376. The remarkable strengthening is predominantly attributed to precipitation hardening. The enhanced mechanical properties of the MMC materials are attributed to the increased dislocation density, and thus, a higher concentration of structural particles compared to the unreinforced materials. Higher gas-to-metal ratios of 4.45, as opposed to lower gas-to-metal ratios of 1.95 produced a refined grain structure with an evenly distributed second phase. In both unreinforced and MMC materials

  16. Corrosion resistance and durability of siloxane ceramic/polymer films for aluminum alloys in marine environments

    NASA Astrophysics Data System (ADS)

    Kusada, Kentaro

    The objective of this study is to evaluate corrosion resistance and durability of siloxane ceramic/polymer films for aluminum alloys in marine environments. Al5052-H3 and Al6061-T6 were selected as substrates, and HCLCoat11 and HCLCoat13 developed in the Hawaii Corrosion Laboratory were selected for the siloxane ceramic/polymer coatings. The HCLCoat11 is a quasi-ceramic coating that has little to no hydrocarbons in its structure. The HCLCoat13 is formulated to incorporate more hydrocarbons to improve adhesion to substrate surfaces with less active functionalities. In this study, two major corrosion evaluation methods were used, which were the polarization test and the immersion test. The polarization tests provided theoretical corrosion rates (mg/dm 2/day) of bare, HCLCoat11-coated, and HCLCoat13-coated aluminum alloys in aerated 3.15wt% sodium chloride solution. From these results, the HCLCoat13-coated Al5052-H3 was found to have the lowest corrosion rate which was 0.073mdd. The next lowest corrosion rate was 0.166mdd of the HCLCoat11-coated Al5052-H3. Corrosion initiation was found to occur at preexisting breaches (pores) in the films by optical microscopy and SEM analysis. The HCLCoat11 film had many preexisting breaches of 1-2microm in diameter, while the HCLCoat13 film had much fewer preexisting breaches of less than 1microm in diameter. However, the immersion tests showed that the seawater immersion made HCLCoat13 film break away while the HCLCoat11 film did not apparently degrade, indicating that the HCLCoat11 film is more durable against seawater than the HCLCoat13. Raman spectroscopy revealed that there was some degradation of HCLCoat11 and HCLCoat13. For the HCLCoat11 film, the structure relaxation of Si-O-Si linkages was observed. On the other hand, seawater generated C-H-S bonds in the HCLCoat13 film resulting in the degradation of the film. In addition, it was found that the HCLCoat11 coating had anti-fouling properties due to its high water contact

  17. Cathodoluminescent properties of an Am3+ ion in a matrix of yttrium-aluminum garnet Y3Al5O12

    NASA Astrophysics Data System (ADS)

    Kuznetsova, Ya. V.; Usacheva, V. P.; Zamoryanskaya, M. V.

    2014-03-01

    The luminescent properties of an americium ion are studied. Luminescence spectra of americium in yttrium-aluminum garnet are recorded for the first time. The luminescence bands are identified, and the levels responsible for the observed optical transitions are determined.

  18. Quasicrystalline particulate reinforced aluminum composite

    SciTech Connect

    Anderson, I.E.; Biner, S.B.; Sordelet, D.J.; Unal, O.

    1997-07-01

    Particulate reinforced aluminum and aluminum alloy composites are rapidly emerging as new commercial materials for aerospace, automotive, electronic packaging and other high performance applications. However, their low processing ductility and difficulty in recyclability have been the key concern. In this study, two composite systems having the same aluminum alloy matrix, one reinforced with quasicrystals and the other reinforced with the conventional SiC reinforcements were produced with identical processing routes. Their processing characteristics and tensile mechanical properties were compared.

  19. Aluminum Hydroxide

    MedlinePlus

    Aluminum hydroxide is used for the relief of heartburn, sour stomach, and peptic ulcer pain and to ... Aluminum hydroxide comes as a capsule, a tablet, and an oral liquid and suspension. The dose and ...

  20. Aluminum-fly ash metal matrix composites for automotive parts. [Reports for October 1 to December 31, 1999, and January 1 - to March 31, 2000

    SciTech Connect

    Weiss, David; Purgert, Robert; Rhudy, Richard; Rohatgi, Pradeep

    2000-04-21

    The highlights of this report are: (1) fly ash classified by less than 100 microns in size was mixed into a 300 lb melt of alloy 535 without the need of a magnesium additive; (2) a vibratory feeder fitted with a sieve was used as the means to minimize particle clustering while introducing fly ash into the aluminum alloy 535 melt; and (3) the industrial-size field test was successful in that sand mold castings and permanent mold castings of tensile bars, K mold bars, and ingots were made from aluminum alloy 535-fly ash mix. Use of aluminum alloy 535 containing 7% magnesium precluded the need to introduce additional magnesium into the melt. The third round of sand mold castings as well as permanent mold castings produced components and ingots of alloy 535 instead of alloy 356. The ingots will be remelted and cast into parts to assess the improvement of flyash distribution which occurs through reheating and the solidification wetting process. Microstructure analysis continues on sand and permanent mold castings to study particle distribution in the components. A prototype sand cast intake manifold casting was found to be pressure tight which is a major performance requirement for this part. Another heat of pressure die cast brackets of A380-classified fly ash will be made to examine their strength and fly ash distribution. Ingots of A356-fly ash have been made at Eck for remelting at Thompson Aluminum for squeeze casting into motor mounts.

  1. Aluminum-fly ash metal matrix composites for automotive parts. [Reports for April 1 to June 30, 1999, and July 1 to September 30, 1999

    SciTech Connect

    Weiss, David; Purgert, Robert; Rhudy, Richard; Rohatgi, P.

    1999-10-15

    Some highlights are: (1) During this quarter's field trials, sand mold castings of parts and permanent mold tensile testing bars, K mold bars, and ingots were made from aluminum alloy-fly ash melts. (2) Another objective was met, i.e., to use class ''F'' type precipitator fly ash consisting of particle sizes less than 100 microns. It was possible to pour the composite melt into the sand mold through a filter. (3) Trials were run to determine the required amount of the wetting agent, magnesium, to ensure appropriate mixing of the aluminum alloy and fly ash. The magnesium content required to mix ''F'' fly ash was much lower compared to that required to mix hybrid ''C-F'' fly ash in similar melts. Fly ash particles of less than 100 microns were mixed in aluminum melt. Large scale field trials were undertaken at Eck Industries with the goal of standardizing procedures for producing aluminum-fly ash composite melts and to analyze the structure and properties of the resulting material. Limited testing of tensile properties has been done on pressure die cast parts, and attempts are underway to improve the distribution of fly ash in both sand cast and pressure die cast samples. Eck Industries performed radiographic, heat treatment, and tensile tests on permanent mold cast tensile test bars. After fly ash mixing experiments, the Lanxide high speed-high shear mixer (originally designed for mixing Al-SiC melts) was employed in an attempt to avoid fly ash agglomeration. It led to demixing (instead of deagglomerating) of some fly ash. However, the permanent mold tensile bars poured after high shear mixing displayed good distribution of fly ash in castings. A modified impeller design is being considered for high speed-high shear mixing of aluminum-fly ash melts.

  2. Properties of largest fragment produced by hypervelocity impact of aluminum spheres with thin aluminum sheets

    NASA Technical Reports Server (NTRS)

    Piekutowski, Andrew J.

    1992-01-01

    Results are presented from hypervelocity impact tests in which 1.275 g spheres of 2017-T4 Al alloy were fired at normal incidence at eight thicknesses of 6061-T6 Al alloy sheets, with impact velocity of about 6.7 km/sec; additional data are presented for smaller and larger spheres than these, in the cases of other Al alloy impact bumpers. A large fragment of the projectile is observable at the center of the debris clouds generated upon impact. The velocity of these large fragments decreased continuously with increasing bumper thickness/projectile diameter ratio, from 99 percent to less than 80 percent of impact velocity; there is a linear increase in the size of the central projectile fragment with decreasing shock-induced stress in the projectile.

  3. Aluminum Analysis.

    ERIC Educational Resources Information Center

    Sumrall, William J.

    1998-01-01

    Presents three problems based on the price of aluminum designed to encourage students to be cooperative and to use an investigative approach to learning. Students collect and synthesize information, analyze results, and draw conclusions. (AIM)

  4. Aluminum Hydroxide

    MedlinePlus

    ... penicillamine (Cuprimine, Depen), prednisone (Deltasone, Orasone), products containing iron, tetracycline (Sumycin, Tetracap, and others), ticlopidine (Ticlid), and vitamins.be aware that aluminum hydroxide may interfere with other medicines, making them less effective. Take your other medications 1 ...

  5. The effect of matrix microstructure on cyclic response and fatigue behavior of particle-reinforced 2219 aluminum: Part II. Behavior at 150 °C

    NASA Astrophysics Data System (ADS)

    Vyletel, G. M.; van Aken, D. C.; Allison, J. E.

    1995-12-01

    The 150 °C cyclic response of peak-aged and overaged 2219/TiC/15p and 2219 Al was examined using fully reversed plastic strain-controlled testing. The cyclic response of peak-aged and overaged particle-reinforced materials showed extensive cyclic softening. This softening began at the commencement of cycling and continued until failure. At a plastic strain below 5 × 103, the unreinforced materials did not show evidence of cyclic softening until approximately 30 pct of the life was consumed. In addition, the degree of cyclic softening (†σ) was significantly lower in the unreinforced microstructures. The cyclic softening in both reinforced and unreinforced materials was attributed to the decomposition of the θ' strengthening precipitates. The extent of the precipitate decomposition was much greater in the composite materials due to the increased levels of local plastic strain in the matrix caused by constrained deformation near the TiC particles.

  6. Active-Transient Liquid Phase (A-TLP) Bonding of Pure Aluminum Matrix Composite Reinforced with Short Alumina Fiber Using Al-12Si-xTi Foils as Active Interlayer

    NASA Astrophysics Data System (ADS)

    Zhang, Guifeng; Su, Wei; Suzumura, Akio

    2016-02-01

    To optimize both the interlayer composition design route and pressure for joining aluminum matrix composite reinforced with short alumina fiber (as-cast 30 vol pct Al2O3sf/Al), traditional transient liquid phase (TLP) bonding using Al-12Si and Cu interlayer and active-TLP (A-TLP) bonding using an active Ti-containing interlayer (Al-12Si-xTi, x = 0.1, 0.5, and 1 wt pct) under the same condition [883 K (610 °C) × 30 minutes × 1 or 0.015 MPa in flowing argon] were compared in terms of interfacial wettability, bond seam microstructure, shear strength, and fracture path. It was found that not only the Ti content but also the pressure are critical factors affecting interfacial wettability and bond seam microstructure. The improvement in wettability by adding Ti as an active element were confirmed by reduction of expulsion of liquid interlayer, elimination of interfacial gap, higher shear strength and favorable fracture path (partially through bond seam and the composite). Because of the incubation period for wetting, reducing the pressure after melting of the interlayer could further increase joint shear strength by thickening the remaining bond seam of solid-solution matrix and decreasing fraction of the in situ newly formed Al-Si-Ti IMC phase (short bar shape) within the bond seam. The maximum shear strength of 88.6 MPa (99 pct of the as-cast composite) was obtained by adding trace Ti content (0.5 Ti wt pct) addition and using low pressure (0.015 MPa). The results showed that suitable combination of Ti content and pressure pattern is required for improving both wettability and bond seam microstructure.

  7. Active-Transient Liquid Phase (A-TLP) Bonding of Pure Aluminum Matrix Composite Reinforced with Short Alumina Fiber Using Al-12Si- xTi Foils as Active Interlayer

    NASA Astrophysics Data System (ADS)

    Zhang, Guifeng; Su, Wei; Suzumura, Akio

    2016-06-01

    To optimize both the interlayer composition design route and pressure for joining aluminum matrix composite reinforced with short alumina fiber (as-cast 30 vol pct Al2O3sf/Al), traditional transient liquid phase (TLP) bonding using Al-12Si and Cu interlayer and active-TLP (A-TLP) bonding using an active Ti-containing interlayer (Al-12Si- xTi, x = 0.1, 0.5, and 1 wt pct) under the same condition [883 K (610 °C) × 30 minutes × 1 or 0.015 MPa in flowing argon] were compared in terms of interfacial wettability, bond seam microstructure, shear strength, and fracture path. It was found that not only the Ti content but also the pressure are critical factors affecting interfacial wettability and bond seam microstructure. The improvement in wettability by adding Ti as an active element were confirmed by reduction of expulsion of liquid interlayer, elimination of interfacial gap, higher shear strength and favorable fracture path (partially through bond seam and the composite). Because of the incubation period for wetting, reducing the pressure after melting of the interlayer could further increase joint shear strength by thickening the remaining bond seam of solid-solution matrix and decreasing fraction of the in situ newly formed Al-Si-Ti IMC phase (short bar shape) within the bond seam. The maximum shear strength of 88.6 MPa (99 pct of the as-cast composite) was obtained by adding trace Ti content (0.5 Ti wt pct) addition and using low pressure (0.015 MPa). The results showed that suitable combination of Ti content and pressure pattern is required for improving both wettability and bond seam microstructure.

  8. Characterization of tool wear and weld optimization in the friction-stir welding of cast aluminum 359+20% SiC metal-matrix composite

    SciTech Connect

    Fernandez, G.J.; Murr, L.E

    2004-03-15

    Tool wear for threaded steel pin tools declines with decreasing rotation speed and increasing traverse or weld speeds for the friction-stir welding (FSW) of Al 359+20% SiC metal-matrix composite (MMC). Less than 10% tool wear occurs when the threaded tool erodes to a self-optimized shape resembling a pseudo-hour glass at weld traverse distances in excess of 3 m. There is only a 7% reduction in the SiC mean particle size in the weld zone for self-optimized pin tools with no threads as compared with a 25% variation for threaded tools wearing significantly at the start of welding. The weld zone becomes more homogeneous for efficient welding with self-optimized tools, and there is a reduction in the weld zone grain size due to dynamic recrystallization, which facilitates the solid-state flow. Transmission electron microscopy shows little difference in the dislocation density from the base material to the weld zone, but there is a propensity of dislocation loops in the weld zone. The weld zone is observed to harden by as much as 30%, in contrast to the base material, as a consequence of the recrystallized grain size reduction and the SiC particles distributed therein.

  9. Aluminum alloy

    NASA Technical Reports Server (NTRS)

    Blackburn, Linda B. (Inventor); Starke, Edgar A., Jr. (Inventor)

    1989-01-01

    This invention relates to aluminum alloys, particularly to aluminum-copper-lithium alloys containing at least about 0.1 percent by weight of indium as an essential component, which are suitable for applications in aircraft and aerospace vehicles. At least about 0.1 percent by weight of indium is added as an essential component to an alloy which precipitates a T1 phase (Al2CuLi). This addition enhances the nucleation of the precipitate T1 phase, producing a microstructure which provides excellent strength as indicated by Rockwell hardness values and confirmed by standard tensile tests.

  10. Metal Matrix Composites

    SciTech Connect

    Hunt, Warren; Herling, Darrell R.

    2004-02-01

    Metal matrix composites have found selected application in areas that can cost-effectively capitalize on improvements in specific stiffness, specific strength, fatigue resistance, wear resistance, and coefficient of thermal expansion. Metal matrix composites comprise a relatively wide range of materials defined by the metal matrix, reinforcement type, and reinforcement geometry. In the area of the matrix, most metallic systems have been explored, including aluminum, beryllium, magnesium, titanium, iron, nickel, cobalt, and silver. However, aluminum is by far the most preferred. For reinforcements, the materials are typically ceramics, which provide a very beneficial combination of stiffness, strength, and relatively low density. Candidate reinforcement materials include SiC, Al2O3, B4C, TiC, TiB2, graphite, and a number of other ceramics. In addition, metallic materials such as tungsten and steel fibers have been considered.

  11. Aluminum phosphide

    Integrated Risk Information System (IRIS)

    Aluminum phosphide ; CASRN 20859 - 73 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

  12. Cracking associated with micrometeoroid impact craters in anodized aluminum alloy clamps on LDEF

    NASA Technical Reports Server (NTRS)

    Murr, Lawrence E.; Niou, Chorng S.; Quinones, Stella; Murr, Kyle S.

    1992-01-01

    The Long Duration Exposure Facility (LDEF) is a reusable hollow-cylindrical satellite sustaining a total of 57 different experiments. The 130 sq m of spacecraft surface area included anodized 6061-T6 Al alloy bay frames and clamps for holding experiment trays in the bay areas. Attention is presently given to the micrometeoroid impact crater features observed on two tray clamps recovered from the LDEF leading-edge locations. It is found that even very subtle surface modifications in structural alloy anodizing can influence micrometeoroid impact crater cracking, notable radial cracking due to the ejecta-rim of the impact craters.

  13. Advances in aluminum casting technology

    SciTech Connect

    Tiryakioglu, M.; Campbell, J.

    1998-01-01

    This symposium focuses on the improvements of aluminum casting quality and reliability through a better understanding of processes and process variables, and explores the latest innovations in casting-process design that allow increasing use of the castings to replace complex assemblies and heavy steel and cast-iron components in aerospace and automotive applications. Presented are 35 papers by international experts in the various aspects of the subject. The contents include: Semisolid casting; Computer-aided designing of molds and castings; Casting-process modeling; Aluminum-matrix composite castings; HIPing of castings; Progress in the US car project; Die casting and die design; and Solidification and properties.

  14. Evaluating of NASA-Langley Research Center explosion seam welding

    NASA Technical Reports Server (NTRS)

    Otto, H. E.; Wittman, R.

    1977-01-01

    An explosion bonding technique to meet current fabrication requirements was demonstrated. A test program was conducted on explosion bonded joints, compared to fusion joints in 6061-T6 aluminum. The comparison was made in required fixtures, non-destructive testing, static strength and fatigue strength.

  15. Galvanic Corrosion In (Graphite/Epoxy)/Alloy Couples

    NASA Technical Reports Server (NTRS)

    Danford, Merlin D.; Higgins, Ralph H.

    1988-01-01

    Effects of galvanic coupling between graphite/epoxy composite material, G/E, and D6AC steel, 6061-T6 aluminum, and Inconel(R) 718 nickel alloy in salt water described in report. Introductory section summarizes previous corrosion studies of G/E with other alloys. Details of sample preparation presented along with photographs of samples before and after immersion.

  16. X-ray photoelectron spectroscopy study of catalyzed aluminum carbide formation at aluminum-carbon interfaces

    NASA Technical Reports Server (NTRS)

    Rabenberg, L.; Maruyama, Benji

    1990-01-01

    Aluminum carbide may form at aluminum-graphite interfaces during the high-temperature processing of graphite fiber-reinforced aluminum metal matrix composites. The chemical interactions leading to the formation of the aluminum carbide in the solid state involve the breaking of the carbon-carbon bonds within the graphite, the transport of the carbon atoms across the interface, and the reaction with the aluminum to form Al4C3. The aluminum carbide formation process has been followed using X-ray photoelectron spectroscopy of model, thin-film, reaction couples. The overall reaction is shown to be catalyzed by the presence of water vapor. Water at the interface increases reaction kinetics by apparently weakening the bonds between the surface carbon atoms and their substrate. This result is in general agreement with what is known to occur during the oxidation of graphite in air.

  17. High conductivity, low cost aluminum composite for thermal management

    SciTech Connect

    Sommer, J.L.

    1997-04-01

    In order to produce an inexpensive packaging material that exhibits high thermal conductivity and low CTE, Technical Research Associates, Inc. (TRA) has shown in Phase I the feasibility of incorporating natural flake graphite in an aluminum matrix. TRA has developed a proprietary coating technique where graphite flakes have been coated with a thin layer of molybdenum/molybdenum carbide (approximately 0.2 microns). This barrier coating can protect the graphite flake from chemical reaction and high temperature degradation in molten aluminum silicon alloys. Methods to successfully vacuum infiltrate coated flake with molten aluminum alloys were developed. The resulted metal matrix composites exhibited lower CTE than aluminum metal. The CTE of the composites were significantly lower than aluminum and its alloys. The CTE can potentially be tailored for specific applications. The in plane thermal conductivity was higher than the aluminum matrix alloy. The thermal conductivity and CTE of the composite may be significantly improved by improving the bond strength of the molybdenum coating on the graphite flake. The flake can potentially be incorporated in the molten aluminum and pressure die cast to align the flakes within the aluminum matrix. By preferentially aligning high conductivity graphite flakes within a plane or direction, the thermal conductivity of the resulting composite will be above pure aluminum in the alignment direction.

  18. Design for aluminum recycling

    SciTech Connect

    Not Available

    1993-10-01

    This article describes the increasing use of aluminum in automobiles and the need to recycle to benefit further growth of aluminum applications by assuring an economical, high-quality source of metal. The article emphasizes that coordination of material specifications among designers can raise aluminum scrap value and facilitate recycling. Applications of aluminum in automobile construction are discussed.

  19. Synthesis of Aluminum-Aluminum Nitride Nanocomposites by a Gas-Liquid Reaction II. Microstructure and Mechanical Properties

    NASA Astrophysics Data System (ADS)

    Borgonovo, Cecilia; Makhlouf, Makhlouf M.

    2016-04-01

    In situ fabrication of the reinforcing particles in the metal matrix is an answer to many of the challenges encountered in manufacturing aluminum matrix nanocomposites. In this method, the nanoparticles are formed directly within the melt by means of a chemical reaction between a specially designed aluminum alloy and a gas. In this publication, we describe a process for synthesizing aluminum-aluminum nitride nanocomposites by reacting a nitrogen-containing gas with a molten aluminum-lithium alloy. We quantify the effect of the process parameters on the average particle size and particle distribution, as well as on the tendency of the particles to cluster in the alloy matrix, is quantified. Also in this publication, we present the measured room temperature and elevated temperature tensile properties of the nanocomposite material as well as its measured room temperature impact toughness.

  20. Aluminum/steel wire composite plates exhibit high tensile strength

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Composite plate of fine steel wires imbedded in an aluminum alloy matrix results in a lightweight material with high tensile strength. Plates have been prepared having the strength of titanium with only 85 percent of its density.

  1. Aluminum Alloy and Article Cast Therefrom

    NASA Technical Reports Server (NTRS)

    Lee, Jonathan A. (Inventor); Chen, Po-Shou (Inventor)

    2003-01-01

    A cast article from an aluminum alloy, which has improved mechanical properties at elevated temperatures, has the following composition in weight percent: Silicon 14 - 25.0, Copper 5.5 - 8.0, Iron 0.05 - 1.2, Magnesium 0.5 - 1.5, Nickel 0.05 - 0.9, Manganese 0.05 - 1.0, Titanium 0.05 - 1.2, Zirconium 0.05 - 1.2, Vanadium 0.05 - 1.2, Zinc 0.05 - 0.9, Phosphorus 0.001 - 0.1, and the balance is Aluminum, wherein the silicon-to-magnesium ratio is 10 - 25, and the copper-to-magnesium ratio is 4 - 15. The aluminum alloy contains a simultaneous dispersion of three types of Al3X compound particles (X=Ti, V, Zr) having a LI2, crystal structure, and their lattice parameters are coherent to the aluminum matrix lattice. A process for producing this cast article is also disclosed, as well as a metal matrix composite, which includes the aluminum alloy serving as a matrix and containing up to about 60% by volume of a secondary filler material.

  2. The Cleaning of Aluminum Frame Assembly Units

    SciTech Connect

    Shen, T H

    2001-05-16

    The Brulin immersion and the precision cleaning experiments have shown that neither the Brulin solution nor the precision cleaning in AstroPak causes the smut formation on aluminum surfaces. The acid-bath cleaning in GTC is the primary source of the smut formation. The current GTC acid formulation etches the aluminum matrix quite aggressively, but does not appear to appreciably attack the Si particles. Therefore, this acid-bath cleaning will leave the cast-aluminum part surfaces with many protruded Si particles, which could potentially cause smut problems in the cleaning process down-stream. To ensure the removal of all loose Si particles from the cast-aluminum parts, it is necessary to physically hand-wipe and vigorously wash the acid-bath cleaned surfaces. Furthermore, the casting porosity in alloy A356 could be another source in causing high swipe readings in the FAU parts.

  3. Evaluation of metal matrix composites

    NASA Technical Reports Server (NTRS)

    Okelly, K. P.

    1971-01-01

    The results of an evaluation of candidate metal-matrix composite materials for shuttle space radiators mounted to external structure are presented. The evaluation was specifically applicable to considerations of the manufacturing and properties of a potential space radiator. Two candidates, boron/aluminum and graphite/aluminum were obtained or made in various forms and tested in sufficient depth to allow selection of one of the two for future scale-up programs. The effort accomplished on this program verified that aluminum reinforced with boron was within the state-of-the-art in industry and possessed properties usable in the external skin areas available for shuttle radiators where re-entry temperatures will not exceed 800 F. It further demonstrated that graphite/aluminum has an apparently attractive future for space applications but requires extension development prior to scale-up.

  4. Aluminum and Young Artists.

    ERIC Educational Resources Information Center

    Anderson, Thomas

    1980-01-01

    The author suggests a variety of ways in which aluminum and aluminum foil can be used in elementary and junior high art classes: relief drawing and rubbing; printing; repousse; sculpture; mobiles; foil sculpture; and three dimensional design. Sources of aluminum supplies are suggested. (SJL)

  5. Fatigue damage accumulation in various metal matrix composites

    NASA Technical Reports Server (NTRS)

    Johnson, W. S.

    1987-01-01

    The purpose of this paper is to review some of the latest understanding of the fatigue behavior of continuous fiber reinforced metal matrix composites. The emphasis is on the development of an understanding of different fatigue damage mechanisms and why and how they occur. The fatigue failure modes in continuous fiber reinforced metal matrix composites are controlled by the three constituents of the system: fiber, matrix, and fiber/matrix interface. The relative strains to fatigue failure of the fiber and matrix will determine the failure mode. Several examples of matrix, fiber, and self-similar damage growth dominated fatigue damage are given for several metal matrix composite systems. Composite analysis, failure modes, and damage modeling are discussed. Boron/aluminum, silicon-carbide/aluminum, FP/aluminum, and borsic/titanium metal matrix composites are discussed.

  6. Aluminum reference electrode

    DOEpatents

    Sadoway, Donald R.

    1988-01-01

    A stable reference electrode for use in monitoring and controlling the process of electrolytic reduction of a metal. In the case of Hall cell reduction of aluminum, the reference electrode comprises a pool of molten aluminum and a solution of molten cryolite, Na.sub.3 AlF.sub.6, wherein the electrical connection to the molten aluminum does not contact the highly corrosive molten salt solution. This is accomplished by altering the density of either the aluminum (decreasing the density) or the electrolyte (increasing the density) so that the aluminum floats on top of the molten salt solution.

  7. Aluminum reference electrode

    DOEpatents

    Sadoway, D.R.

    1988-08-16

    A stable reference electrode is described for use in monitoring and controlling the process of electrolytic reduction of a metal. In the case of Hall cell reduction of aluminum, the reference electrode comprises a pool of molten aluminum and a solution of molten cryolite, Na[sub 3]AlF[sub 6], wherein the electrical connection to the molten aluminum does not contact the highly corrosive molten salt solution. This is accomplished by altering the density of either the aluminum (decreasing the density) or the electrolyte (increasing the density) so that the aluminum floats on top of the molten salt solution. 1 fig.

  8. Aluminum-lithium target behavior

    SciTech Connect

    McDonell, W.R.

    1989-10-01

    Information on physical properties and irradiation behavior of aluminum-lithium target alloys employed for the production of tritium in Savannah River reactors has been reviewed to support development of technology for the New Production Reactor (NPR). Phase compositions and microstructures, thermal conductivity, mechanical properties, and constituent diffusion phenomena of the alloys, established in prior site studies, are presented. Irradiation behavior, including distributions of product tritium and helium and related exposure limits due to swelling and cracking of the target alloys is discussed, along with gas release processes occurring during subsequent product recovery operations. The property review supports designation of the aluminum-lithium alloys as ideally well-suited target materials for low-temperature, tritium-producing reactors, demonstrated over 35 years of Savannah River reactor operation. Low temperature irradiation and reaction with lithium in the alloy promotes tritium retention during reactor exposure, and the aluminum provides a matrix from which the product is readily recovered on heating following irradiation. 33 refs., 26 figs., 8 tabs.

  9. Aluminum: Recycling of Aluminum Dross/Saltcake

    SciTech Connect

    Blazek, S.

    1999-01-29

    As this NICE3 publication details, the objective of this project is to commercialize the process technology to eliminate all landfill waste associated with black dross and saltcake generated from aluminum recycling in the United States.

  10. Aluminum powder metallurgy processing

    NASA Astrophysics Data System (ADS)

    Flumerfelt, Joel Fredrick

    In recent years, the aluminum powder industry has expanded into non-aerospace applications. However, the alumina and aluminum hydroxide in the surface oxide film on aluminum powder require high cost powder processing routes. A driving force for this research is to broaden the knowledge base about aluminum powder metallurgy to provide ideas for fabricating low cost aluminum powder components. The objective of this dissertation is to explore the hypothesis that there is a strong linkage between gas atomization processing conditions, as-atomized aluminum powder characteristics, and the consolidation methodology required to make components from aluminum powder. The hypothesis was tested with pure aluminum powders produced by commercial air atomization commercial inert gas atomization and gas atomization reaction synthesis (GARS). The commercial atomization methods are bench marks of current aluminum powder technology. The GARS process is a laboratory scale inert gas atomization facility. A benefit of using pure aluminum powders is an unambiguous interpretation of the results without considering the effects of alloy elements. A comparison of the GARS aluminum powders with the commercial aluminum powders showed the former to exhibit superior powder characteristics. The powders were compared in terms of size and shape, bulk chemistry, surface oxide chemistry and structure, and oxide film thickness. Minimum explosive concentration measurements assessed the dependence of explosibility hazard on surface area, oxide film thickness, and gas atomization processing conditions. The GARS aluminum powders were exposed to different relative humidity levels, demonstrating the effect of atmospheric conditions on post-atomization oxidation of aluminum powder. An Al-Ti-Y GARS alloy exposed in ambient air at different temperatures revealed the effect of reactive alloy elements on post-atomization powder oxidation. The pure aluminum powders were consolidated by two different routes, a

  11. Synthesis of Aluminum-Aluminum Nitride Nanocomposites by Gas-Liquid Reactions I. Thermodynamic and Kinetic Considerations

    NASA Astrophysics Data System (ADS)

    Borgonovo, Cecilia; Makhlouf, Makhlouf M.

    2016-07-01

    In-situ fabrication of the reinforcing particles directly in the metal matrix is an answer to many of the challenges encountered in manufacturing metal matrix nanocomposite materials. In this method, the nanosized particles are formed directly within the melt by means of a chemical reaction between a specially designed metallic alloy and a reactive gas. The thermodynamic and kinetic characteristics of this chemical reaction dictate the particle size and distribution in the matrix alloy, as well as the nature of the particle/matrix interface, and consequently, they govern many of the material's mechanical and physical properties. This article focuses on aluminum-aluminum-nitride nanocomposite materials that are synthesized by injecting a nitrogen-bearing gas into a molten aluminum alloy. The thermodynamic and kinetic aspects of the process are modeled, and the detrimental role of oxygen is elucidated.

  12. Preliminary Investigation of Zircaloy-4 as a Research Reactor Cladding Material

    SciTech Connect

    Brian K Castle

    2012-05-01

    As part of a scoping study for the ATR fuel conversion project, an initial comparison of the material properties of Zircaloy-4 and Aluminum-6061 (T6 and O-temper) is performed to provide a preliminary evaluation of Zircaloy-4 for possible inclusion as a candidate cladding material for ATR fuel elements. The current fuel design for the ATR uses Aluminum 6061 (T6 and O temper) as a cladding and structural material in the fuel element and to date, no fuel failures have been reported. Based on this successful and longstanding operating history, Zircaloy-4 properties will be evaluated against the material properties for aluminum-6061. The preliminary investigation will focus on a comparison of density, oxidation rates, water chemistry requirements, mechanical properties, thermal properties, and neutronic properties.

  13. Interactions of satellite-speed helium atoms with satellite surfaces. 2: Energy distributions of reflected helium atoms

    NASA Technical Reports Server (NTRS)

    Liu, S. M.; Knuth, E. L.

    1976-01-01

    Energy transfer in collisions of satellite-speed (7,000 m/sec) helium atoms with a cleaned 6061-T6 satellite-type aluminum surface was investigated using the molecular-beam technique. The amount of energy transferred was determined from the measured energy of the molecular-beam and the measured spatial and energy distributions of the reflected atoms. Spatial distributions of helium atoms scattered from a 6061-T6 aluminum surface were measured. The scattering pattern exhibits a prominent backscattering, probably due to the gross surface roughness and/or the relative lattice softness of the aluminum surface. Energy distributions of reflected helium atoms from the same surface were measured for six different incidence angles. For each incidence angle, distributions were measured at approximately sixty scattering positions. At a given scattering position, the energy spectra of the reflected helium atoms and the background gas were obtained using the retarding-field energy analyzer.

  14. Aspects of aluminum toxicity

    SciTech Connect

    Hewitt, C.D.; Savory, J.; Wills, M.R. )

    1990-06-01

    Aluminum is the most abundant metal in the earth's crust. The widespread occurrence of aluminum, both in the environment and in foodstuffs, makes it virtually impossible for man to avoid exposure to this metal ion. Attention was first drawn to the potential role of aluminum as a toxic metal over 50 years ago, but was dismissed as a toxic agent as recently as 15 years ago. The accumulation of aluminum, in some patients with chronic renal failure, is associated with the development of toxic phenomena; dialysis encephalopathy, osteomalacic dialysis osteodystrophy, and an anemia. Aluminum accumulation also occurs in patients who are not on dialysis, predominantly infants and children with immature or impaired renal function. Aluminum has also been implicated as a toxic agent in the etiology of Alzheimer's disease, Guamiam amyotrophic lateral sclerosis, and parkinsonism-dementia. 119 references.

  15. Fatigue crack propagation in aerospace aluminum alloys

    NASA Technical Reports Server (NTRS)

    Gangloff, R. P.; Piascik, R. S.; Dicus, D. L.; Newman, J. C., Jr.

    1990-01-01

    This paper reviews fracture mechanics based, damage tolerant characterizations and predictions of fatigue crack growth in aerospace aluminum alloys. The results of laboratory experimentation and modeling are summarized in the areas of: (1) fatigue crack closure, (2) the wide range crack growth rate response of conventional aluminum alloys, (3) the fatigue behavior of advanced monolithic aluminum alloys and metal matrix composites, (4) the short crack problem, (5) environmental fatigue, and (6) variable amplitude loading. Remaining uncertainties and necessary research are identified. This work provides a foundation for the development of fatigue resistant alloys and composites, next generation life prediction codes for new structural designs and extreme environments, and to counter the problem of aging components.

  16. Lithium-aluminum-magnesium electrode composition

    DOEpatents

    Melendres, Carlos A.; Siegel, Stanley

    1978-01-01

    A negative electrode composition is presented for use in a secondary, high-temperature electrochemical cell. The cell also includes a molten salt electrolyte of alkali metal halides or alkaline earth metal halides and a positive electrode including a chalcogen or a metal chalcogenide as the active electrode material. The negative electrode composition includes up to 50 atom percent lithium as the active electrode constituent and a magnesium-aluminum alloy as a structural matrix. Various binary and ternary intermetallic phases of lithium, magnesium, and aluminum are formed but the electrode composition in both its charged and discharged state remains substantially free of the alpha lithium-aluminum phase and exhibits good structural integrity.

  17. Effect of copper and magnesium on the structure and the phase composition of boron/aluminum composite ingots

    NASA Astrophysics Data System (ADS)

    Belov, N. A.; Samoshina, M. E.; Alabin, A. N.; Chervyakova, K. Yu.

    2016-01-01

    The phase composition of aluminum Al-B-Cu-Mg alloys has been studied using calculations and experimental methods. Unlike copper, magnesium is shown to substitute aluminum in the AlB2 phase substantially. The use of Al-Cu-Mg alloys (duraluminums) as the matrix of boron/aluminum composite prepared by liquid-phase technologies is substantiated.

  18. BONDING ALUMINUM METALS

    DOEpatents

    Noland, R.A.; Walker, D.E.

    1961-06-13

    A process is given for bonding aluminum to aluminum. Silicon powder is applied to at least one of the two surfaces of the two elements to be bonded, the two elements are assembled and rubbed against each other at room temperature whereby any oxide film is ruptured by the silicon crystals in the interface; thereafter heat and pressure are applied whereby an aluminum-silicon alloy is formed, squeezed out from the interface together with any oxide film, and the elements are bonded.

  19. Aluminum powder metallurgy processing

    SciTech Connect

    Flumerfelt, J.F.

    1999-02-12

    The objective of this dissertation is to explore the hypothesis that there is a strong linkage between gas atomization processing conditions, as-atomized aluminum powder characteristics, and the consolidation methodology required to make components from aluminum powder. The hypothesis was tested with pure aluminum powders produced by commercial air atomization, commercial inert gas atomization, and gas atomization reaction synthesis (GARS). A comparison of the GARS aluminum powders with the commercial aluminum powders showed the former to exhibit superior powder characteristics. The powders were compared in terms of size and shape, bulk chemistry, surface oxide chemistry and structure, and oxide film thickness. Minimum explosive concentration measurements assessed the dependence of explosibility hazard on surface area, oxide film thickness, and gas atomization processing conditions. The GARS aluminum powders were exposed to different relative humidity levels, demonstrating the effect of atmospheric conditions on post-atomization processing conditions. The GARS aluminum powders were exposed to different relative humidity levels, demonstrating the effect of atmospheric conditions on post-atomization oxidation of aluminum powder. An Al-Ti-Y GARS alloy exposed in ambient air at different temperatures revealed the effect of reactive alloy elements on post-atomization powder oxidation. The pure aluminum powders were consolidated by two different routes, a conventional consolidation process for fabricating aerospace components with aluminum powder and a proposed alternative. The consolidation procedures were compared by evaluating the consolidated microstructures and the corresponding mechanical properties. A low temperature solid state sintering experiment demonstrated that tap densified GARS aluminum powders can form sintering necks between contacting powder particles, unlike the total resistance to sintering of commercial air atomization aluminum powder.

  20. Carbothermic Aluminum Production Using Scrap Aluminum As A Coolant

    DOEpatents

    LaCamera, Alfred F.

    2002-11-05

    A process for producing aluminum metal by carbothermic reduction of alumina ore. Alumina ore is heated in the presence of carbon at an elevated temperature to produce an aluminum metal body contaminated with about 10-30% by wt. aluminum carbide. Aluminum metal or aluminum alloy scrap then is added to bring the temperature to about 900-1000.degree. C. and precipitate out aluminum carbide. The precipitated aluminum carbide is filtered, decanted, or fluxed with salt to form a molten body having reduced aluminum carbide content.

  1. MTBE OXIDATION BY BIFUNCTIONAL ALUMINUM

    EPA Science Inventory

    Bifunctional aluminum, prepared by sulfating zero-valent aluminum with sulfuric acid, has a dual functionality of simultaneously decomposing both reductively- and oxidatively-degradable contaminants. In this work, the use of bifunctional aluminum for the degradation of methyl te...

  2. Studies on aluminum neurotoxicity

    SciTech Connect

    Cho, S.

    1988-01-01

    This work reports the inhibitory effects of aluminum on glucose-6-phosphate dehydrogenase (G6PD) from yeast and brains. The aluminum contents and several enzyme activities in aluminum-fed rat brain homogenates were compared with those in age-matched control groups. The concentration of aluminum in the homogenates of the aluminum-fed groups were twice of that of the controls. Acetylcholinesterase activities were the same as in both groups but hexokinase and G6PD activities in the aluminum-fed group were about 73% and 70% of the control, respectively. Further studies on the inhibitory effects of aluminum on G6PD were performed with the enzymes purified from human and pig brains. Two forms of G6PD isozymes were purified from human and pig brain by ammonium sulfate fractionation, hydroxylapatite chromatography, affinity chromatography with NADP-agarose and Blue-Sepharose CL-6B, and gel filtration with Sephadex S-300. The two forms of isozymes (isozyme I and II), purified to be homogeneous, had a molecular weight of 220,000, and composed of 4 subunits of molecular weight of 57,000. HPLC peptide maps of tryptic digests and amino acid analyses of the isozymes showed extensive homologies between the isozymes. Interestingly, only the isozyme II in human and pig brain were active with 6-phosphogluconate as a substrate. No such an activity was found in isozyme I. Aluminum inactivated G6PD activity of the human and pig brain isozyme I and isozyme II without affecting the 6-phosphogluconate dehydrogenase activity of the isozyme II. Circular dichroism studies showed that the binding of aluminum to G6PD induced a decrease in {alpha}-helix and {beta}-sheet and a increase in random coil. Therefore it is suggested that inactivation of G6PD by aluminum is due to the conformational change induced by aluminum binding.

  3. Aluminum: Reducing chloride emissions from aluminum production

    SciTech Connect

    Simon, P.

    1999-09-29

    Reynolds Metals Company (RMC), with assistance from a NICE{sup 3} grant, is developing for commercialization a closed-loop control process that greatly reduces chlorine emissions and increases plant efficiency while maintaining metal quality. The process still utilizes chlorine to remove impurities during aluminum processing, but is more effective than current methods. With the new technology chlorine in the stack is monitored and input chlorine is adjusted continuously. This optimization of chlorine use results in substantially less waste because less chlorine has to be bought or produced by aluminum manufacturers. This innovation is a significant improvement over conventional aluminum treatments, in which chlorine is injected in a more costly and wasteful manner. By the year 2010, the new technology has the potential to reduce the energy it takes to create chlorine by 8.4 billion Btu per year and to cut greenhouse gas emissions by 1,377 tons per year.

  4. Low Temperature Aluminum Dissolution Of Sludge Waste

    SciTech Connect

    Keefer, M.T.; Hamm, B.A.; Pike, J.A.

    2008-07-01

    High Level Waste (HLW) at the Savannah River Site (SRS) is currently stored in aging underground storage tanks. This waste is a complex mixture of insoluble solids, referred to as sludge, and soluble salts. Continued long-term storage of these radioactive wastes poses an environmental risk. The sludge is currently being stabilized in the Defense Waste Processing Facility (DWPF) through a vitrification process immobilizing the waste in a borosilicate glass matrix for long-term storage in a federal repository. Without additional treatment, the existing volume of sludge would produce nearly 8000 canisters of vitrified waste. Aluminum compounds, along with other non-radioactive components, represent a significant portion of the sludge mass currently planned for vitrification processing in DWPF. Removing the aluminum from the waste stream reduces the volume of sludge requiring vitrification and improves production rates. Treating the sludge with a concentrated sodium hydroxide (caustic) solution at elevated temperatures (>90 deg. C) to remove aluminum is part of an overall sludge mass reduction effort to reduce the number of vitrified canisters, shorten the life cycle for the HLW system, and reduce the risk associated with the long term storage of radioactive wastes at SRS. A projected reduction of nearly 900 canisters will be achieved by performing aluminum dissolution on six targeted sludge batches; however, a project to develop and install equipment will not be ready for operation until 2013. The associated upgrades necessary to implement a high temperature process in existing facilities are costly and present many technical challenges. Efforts to better understand the characteristics of the sludge mass and dissolution kinetics are warranted to overcome these challenges. Opportunities to further reduce the amount of vitrified waste and increase production rates should also be pursued. Sludge staged in Tank 51 as the next sludge batch for feed to DWPF consisted

  5. Effects of thermal cycling on density, elastic modulus, and vibrational damping in an alumina particulate reinforced aluminum metal matrix composite (Al{sub 2}O{sub 3p}/2014 Al)

    SciTech Connect

    Wolfenden, A.; Tang, H.H.; Chawla, K.; Hermel, T.

    1999-07-01

    The effects of thermal cycling on the mechanical and physical properties, namely, the density, dynamic elastic modulus and vibrational damping, were measured for a particular reinforced metal matrix composite (MMC). The material was made by Duralcan. Specimens were exposed to up thermal cycles from room temperature to 300 C. The density of the material was measured by the Archimedes technique. The dynamic Young`s Modulus and vibrational damping of the material were determined by the piezoelectric ultrasonic composite oscillator technique (PUCOT). The results showed that the density and elastic modulus of the material increased only slightly due to the thermal cycling while the damping increased significantly. An increase in dislocation concentration near the particle/matrix interfaces caused by the thermal cycling could account for the measured results.

  6. Aluminum space frame technology

    SciTech Connect

    Birch, S.

    1994-01-01

    This article examines the increased application of aluminum to the construction of automobile frames. The topics of the article include a joint venture between Audi and Alcoa, forms in which aluminum is used, new alloys and construction methods, meeting rigidity and safety levels, manufacturing techniques, the use of extrusions, die casting, joining techniques, and pollution control during manufacturing.

  7. Anodizing Aluminum with Frills.

    ERIC Educational Resources Information Center

    Doeltz, Anne E.; And Others

    1983-01-01

    "Anodizing Aluminum" (previously reported in this journal) describes a vivid/relevant laboratory experience for general chemistry students explaining the anodizing of aluminum in sulfuric acid and constrasting it to electroplating. Additions to this procedure and the experiment in which they are used are discussed. Reactions involved are also…

  8. Cast aluminum denture base.

    PubMed

    Barco, M T; Dembert, M L

    1987-08-01

    The laboratory procedures for a cast aluminum base denture have been presented. If an induction casting machine is not available, the "two-oven technique" works well, provided the casting arm is kept spinning manually for 4 minutes after casting. If laboratory procedures are executed precisely and with care, the aluminum base denture can be cast with good results. PMID:3305884

  9. Is the Aluminum Hypothesis Dead?

    PubMed Central

    2014-01-01

    The Aluminum Hypothesis, the idea that aluminum exposure is involved in the etiology of Alzheimer disease, dates back to a 1965 demonstration that aluminum causes neurofibrillary tangles in the brains of rabbits. Initially the focus of intensive research, the Aluminum Hypothesis has gradually been abandoned by most researchers. Yet, despite this current indifference, the Aluminum Hypothesis continues to attract the attention of a small group of scientists and aluminum continues to be viewed with concern by some of the public. This review article discusses reasons that mainstream science has largely abandoned the Aluminum Hypothesis and explores a possible reason for some in the general public continuing to view aluminum with mistrust. PMID:24806729

  10. The aluminum smelting process.

    PubMed

    Kvande, Halvor

    2014-05-01

    This introduction to the industrial primary aluminum production process presents a short description of the electrolytic reduction technology, the history of aluminum, and the importance of this metal and its production process to modern society. Aluminum's special qualities have enabled advances in technologies coupled with energy and cost savings. Aircraft capabilities have been greatly enhanced, and increases in size and capacity are made possible by advances in aluminum technology. The metal's flexibility for shaping and extruding has led to architectural advances in energy-saving building construction. The high strength-to-weight ratio has meant a substantial reduction in energy consumption for trucks and other vehicles. The aluminum industry is therefore a pivotal one for ecological sustainability and strategic for technological development. PMID:24806722

  11. Aluminum structural applications

    SciTech Connect

    Lucas, G.

    1996-05-01

    Extensive research by aluminum producers and automakers in the 1980s resulted in the development of technologies that enable building of aluminum cars that meet and exceed all the expectations of today`s drivers and passengers, yet weigh several hundred pounds less than their steel counterparts. The Acura NSX sports car, the Audi A8, and the Jaguar XJ220 have all been introduced. Ford has built 40 aluminum-intensive automobiles based on the Taurus/Sable for test purposes, and General Motors recently announced an aluminum-structured electric vehicle. The design flexibility that aluminum allows is shown by these examples. Each uses a somewhat different technology that is particularly suited to the vehicle and its market.

  12. The Aluminum Smelting Process

    PubMed Central

    2014-01-01

    This introduction to the industrial primary aluminum production process presents a short description of the electrolytic reduction technology, the history of aluminum, and the importance of this metal and its production process to modern society. Aluminum's special qualities have enabled advances in technologies coupled with energy and cost savings. Aircraft capabilities have been greatly enhanced, and increases in size and capacity are made possible by advances in aluminum technology. The metal's flexibility for shaping and extruding has led to architectural advances in energy-saving building construction. The high strength-to-weight ratio has meant a substantial reduction in energy consumption for trucks and other vehicles. The aluminum industry is therefore a pivotal one for ecological sustainability and strategic for technological development. PMID:24806722

  13. Clinical biochemistry of aluminum

    SciTech Connect

    King, S.W.; Savory, J.; Wills, M.R.

    1981-05-01

    Aluminum toxicity has been implicated in the pathogenesis of a number of clinical disorders in patients with chronic renal failure on long-term intermittent hemodialysis treatment. The predominant disorders have been those involving either bone (osteomalacic dialysis osteodystrophy) or brain (dialysis encephalopathy). In nonuremic patients, an increased brain aluminum concentration has been implicated as a neurotoxic agent in the pathogenesis of Alzheimer's disease and was associated with experimental neurofibrillary degeneration in animals. The brain aluminum concentrations of patients dying with the syndrome of dialysis encephalopathy (dialysis dementia) are significantly higher than in dialyzed patients without the syndrome and in nondialyzed patients. Two potential sources for the increased tissue content of aluminum in patients on hemodialysis have been proposed: (1) intestinal absorption from aluminum containing phosphate-binding gels, and (2) transfer across the dialysis membrane from aluminum in the water used to prepare the dialysate. These findings, coupled with our everyday exposure to the ubiquitous occurrence of aluminum in nature, have created concerns over the potential toxicity of this metal.

  14. Electron Positron Proton Spectrometer for use at Laboratory for Laser Energetics

    SciTech Connect

    Ayers, S L

    2010-04-07

    The Electron Positron Proton Spectrometer (EPPS) is mounted in a TIM (Ten-Inch Manipulator) system on the Omega-60 or Omega-EP laser facilities at the University of Rochester, Laboratory for Laser Energetics (LLE), when in use, see Fig. 1. The Spectrometer assembly, shown in Fig. 2, is constructed of a steel box containing magnets, surrounded by Lead 6% Antimony shielding with SS threaded insert, sitting on an Aluminum 6061-T6 plate.

  15. Purifying Aluminum by Vacuum Distillation

    NASA Technical Reports Server (NTRS)

    Du Fresne, E. R.

    1985-01-01

    Proposed method for purifying aluminum employs one-step vacuum distillation. Raw material for process impure aluminum produced in electrolysis of aluminum ore. Impure metal melted in vacuum. Since aluminum has much higher vapor pressure than other constituents, boils off and condenses on nearby cold surfaces in proportions much greater than those of other constituents.

  16. Advances in aluminum anodizing

    NASA Technical Reports Server (NTRS)

    Dale, K. H.

    1969-01-01

    White anodize is applied to aluminum alloy surfaces by specific surface preparation, anodizing, pigmentation, and sealing techniques. The development techniques resulted in alloys, which are used in space vehicles, with good reflectance values and excellent corrosive resistance.

  17. Walnut Hulls Clean Aluminum

    NASA Technical Reports Server (NTRS)

    Colberg, W. R.; Gordon, G. H.; Jackson, C. H.

    1984-01-01

    Hulls inflict minimal substrate damage. Walnut hulls found to be best abrasive for cleaning aluminum surfaces prior to painting. Samples blasted with walnut hulls showed no compressive stress of surface.

  18. Corrosion Inhibitors for Aluminum.

    ERIC Educational Resources Information Center

    Muller, Bodo

    1995-01-01

    Describes a simple and reliable test method used to investigate the corrosion-inhibiting effects of various chelating agents on aluminum pigments in aqueous alkaline media. The experiments that are presented require no complicated or expensive electronic equipment. (DDR)

  19. CORROSION PROTECTION OF ALUMINUM

    DOEpatents

    Dalrymple, R.S.; Nelson, W.B.

    1963-07-01

    Treatment of aluminum-base metal surfaces in an autoclave with an aqueous chromic acid solution of 0.5 to 3% by weight and of pH below 2 for 20 to 50 hrs at 160 to 180 deg C produces an extremely corrosion-resistant aluminum oxidechromium film on the surface. A chromic acid concentration of 1 to 2% and a pH of about 1 are preferred. (D.C.W.)

  20. Corrosion Protection of Aluminum

    DOEpatents

    Dalrymple, R. S.; Nelson, W. B.

    1963-07-01

    Treatment of aluminum-base metal surfaces in an autoclave with an aqueous chromic acid solution of 0.5 to 3% by weight and of pH below 2 for 20 to 50 hrs at 160 to 180 deg C produces an extremely corrosion-resistant aluminum oxidechromium film on the surface. A chromic acid concentration of 1 to 2% and a pH of about 1 are preferred.

  1. Light weight aluminum optics

    NASA Astrophysics Data System (ADS)

    Catura, R. C.; Vieira, J. R.

    1985-09-01

    Light weight mirror blanks were fabricated by dip-brazing a core of low mass aluminum foam material to thin face sheets of solid aluminum. The blanks weigh 40% of an equivalent size solid mirror and were diamond turned to provide reflective surfaces. Optical interferometry was used to assess their dimensional stability over 7 months. No changes in flatness are observed (to the sensitivity of the measurements of a half wavelength of red light).

  2. Preliminary fracture analysis of the core pressure boundary tube for the Advanced Neutron Source Research Reactor

    SciTech Connect

    Schulz, K.C.; Yahr, G.T.

    1995-08-01

    The outer core pressure boundary tube (CPBT) of the Advanced neutron Source (ANS) reactor being designed at Oak Ridge National Laboratory is currently specified as being composed of 6061-T6 aluminum. ASME Boiler and Pressure Vessel Code fracture analysis rules for nuclear components are based on the use of ferritic steels; the expressions, tables, charts and equations were all developed from tests and analyses conducted for ferritic steels. Because of the nature of the Code, design with thin aluminum requires analytical approaches that do not directly follow the Code. The intent of this report is to present a methodology comparable to the ASME Code for ensuring the prevention of nonductile fracture of the CPBT in the ANS reactor. 6061-T6 aluminum is known to be a relatively brittle material; the linear elastic fracture mechanics (LEFM) approach is utilized to determine allowable flaw sizes for the CPBT. A J-analysis following the procedure developed by the Electric Power Research Institute was conducted as a check; the results matched those for the LEFM analysis for the cases analyzed. Since 6061-T6 is known to embrittle when irradiated, the reduction in K{sub Q} due to irradiation is considered in the analysis. In anticipation of probable requirements regarding maximum allowable flaw size, a survey of nondestructive inspection capabilities is also presented. A discussion of probabilistic fracture mechanics approaches, principally Monte Carlo techniques, is included in this report as an introduction to what quantifying the probability of nonductile failure of the CPBT may entail.

  3. Polymer Matrix Composite Material Oxygen Compatibility

    NASA Technical Reports Server (NTRS)

    Owens, Tom

    2001-01-01

    Carbon fiber/polymer matrix composite materials look promising as a material to construct liquid oxygen (LOX) tanks. Based on mechanical impact tests the risk will be greater than aluminum, however, the risk can probably be managed to an acceptable level. Proper tank design and operation can minimize risk. A risk assessment (hazard analysis) will be used to determine the overall acceptability for using polymer matrix composite materials.

  4. High Strength Aluminum Alloy For High Temperature Applications

    NASA Technical Reports Server (NTRS)

    Lee, Jonathan A. (Inventor); Chen, Po-Shou (Inventor)

    2005-01-01

    A cast article from an aluminum alloy has improved mechanical properties at elevated temperatures. The cast article has the following composition in weight percent: Silicon 6.0-25.0, Copper 5.0-8.0, Iron 0.05-1.2, Magnesium 0.5-1.5, Nickel 0.05-0.9, Manganese 0.05-1.2, Titanium 0.05-1.2, Zirconium 0.05-1.2, Vanadium 0.05-1.2, Zinc 0.05-0.9, Strontium 0.001-0.1, Phosphorus 0.001-0.1, and the balance is Aluminum, wherein the silicon-to-magnesium ratio is 10-25, and the copper-to-magnesium ratio is 4-15. The aluminum alloy contains a simultaneous dispersion of three types of Al3X compound particles (X=Ti, V, Zr) having a LI2 crystal structure, and their lattice parameters are coherent to the aluminum matrix lattice. A process for producing this cast article is also disclosed, as well as a metal matrix composite, which includes the aluminum alloy serving as a matrix containing up to about 60% by volume of a secondary filler material.

  5. Analysis of notched metal matrix composites under tension loading

    NASA Technical Reports Server (NTRS)

    Bigelow, C. A.

    1988-01-01

    Presented are techniques based on 3-D finite-element analysis for the examination of continuous fiber reinforced metal matrix composites. Examples are shown for specific metal matrix composites such as boron/aluminum and silicon-carbide/aluminum. Specimen stress-strain behavior and stress at first fiber failure were predicted for boron/aluminum laminates containing circular holes and crack-like slits. The predictions compared very well for (+ or - 45) sub 2s laminates. Mesh configuration was shown to have an effect on the calculation of stresses local to the notch. The presence of thin interface layers of matrix material had a significant influence on the slit-tip stress state, causing sharper stress gradients near the notch. Interface layers reduced the slit-tip fibers stresses in a (+ or - 45) sub s silicon-carbide/aluminum laminate but increased them in a (0/90) sub s laminate.

  6. Aluminum, parathyroid hormone, and osteomalacia

    SciTech Connect

    Burnatowska-Hledin, M.A.; Kaiser, L.; Mayor, G.H.

    1983-01-01

    Aluminum exposure in man is unavoidable. The occurrence of dialysis dementia, vitamin D-resistant osteomalacia, and hypochromic microcytic anemia in dialysis patients underscores the potential for aluminum toxicity. Although exposure via dialysate and hyperalimentation leads to significant tissue aluminum accumulation, the ubiquitous occurrence of aluminum and the severe pathology associated with large aluminum burdens suggest that smaller exposures via the gastrointestinal tract and lungs could represent an important, though largely unrecognized, public health problem. It is clear that some aluminum absorption occurs with the ingestion of small amounts of aluminum in the diet and medicines, and even greater aluminum absorption is seen in individuals consuming large amounts of aluminum present in antacids. Aluminum absorption is enhanced in the presence of elevated circulating parathyroid hormone. In addition, elevated PTH leads to the preferential deposition of aluminum in brain and bone. Consequently, PTH is likely to be involved in the pathogenesis of toxicities in those organs. PTH excess also seems to lead to the deposition of aluminum in the parathyroid gland. The in vitro demonstration that aluminum inhibits parathyroid hormone release is consistent with the findings of a euparathyroid state in dialysis patients with aluminum related vitamin D-resistant osteomalacia. Nevertheless, it seems likely that hyperparathyroidism is at least initially involved in the pathogenesis of aluminum neurotoxicity and osteomalacia; the increases in tissue aluminum stores are followed by suppression of parathyroid hormone release, which is required for the evolution of osteomalacia. Impaired renal function is not a prerequisite for increased tissue aluminum burdens, nor for aluminum-related organ toxicity. Consequently, it is likely that these diseases will be observed in populations other than those with chronic renal disease.

  7. Lightweight Aluminum/Nano composites for Automotive Drive Train Applications

    SciTech Connect

    Chelluri, Bhanumathi; Knoth, Edward A.; Schumaker, Edward J.

    2012-12-14

    During Phase I, we successfully processed air atomized aluminum powders via Dynamic Magnetic Compaction (DMC) pressing and subsequent sintering to produce parts with properties similar to wrought aluminum. We have also showed for the first time that aluminum powders can be processed without lubes via press and sintering to 100 % density. This will preclude a delube cycle in sintering and promote environmentally friendly P/M processing. Processing aluminum powders via press and sintering with minimum shrinkage will enable net shape fabrication. Aluminum powders processed via a conventional powder metallurgy process produce too large a shrinkage. Because of this, sinter parts have to be machined into specific net shape. This results in increased scrap and cost. Fully sintered aluminum alloy under this Phase I project has shown good particle-to-particle bonding and mechanical properties. We have also shown the feasibility of preparing nano composite powders and processing via pressing and sintering. This was accomplished by dispersing nano silicon carbide (SiC) powders into aluminum matrix comprising micron-sized powders (<100 microns) using a proprietary process. These composite powders of Al with nano SiC were processed using DMC press and sinter process to sinter density of 85-90%. The process optimization along with sintering needs to be carried out to produce full density composites.

  8. Nonlinear response of unidirectional boron/aluminum

    NASA Technical Reports Server (NTRS)

    Pindera, M.-J.; Herakovich, C. T.; Becker, W.; Aboudi, J.

    1990-01-01

    Experimental results obtained for unidirectional boron/aluminum subjected to combined loading using off-axis tension, compression and Iosipescu shear specimens are correlated with a nonlinear micromechanics model. It is illustrated that the nonlinear response in the principal material directions is markedly influenced by the different loading modes and different ratios of the applied stress components. The observed nonlinear response under pure and combined loading is discussed in terms of initial yielding, subsequent hardening, stress-interaction effects and unloading-reloading characteristics. The micromechanics model is based on the concept of a repeating unit cell representative of the composite-at-large and employs the unified theory of Bodner and Partom to model the inelastic response of the matrix. It is shown that the employed micromechanics model is sufficiently general to predict the observed nonlinear response of unidirectional boron/aluminum with good accuracy.

  9. ALUMINUM RECLAMATION BY ACIDIC EXTRACTION OF ALUMINUM-ANODIZING SLUDGES

    EPA Science Inventory

    Extraction of aluminum-anodizing sludges with sulfuric acid was examined to determine the potential for production of commercial-strength solutions of aluminum sulfate, that is liquid alum. The research established kinetic and stoichiometric relationships and evaluates product qu...

  10. Matrix superpotentials

    NASA Astrophysics Data System (ADS)

    Nikitin, Anatoly G.; Karadzhov, Yuri

    2011-07-01

    We present a collection of matrix-valued shape invariant potentials which give rise to new exactly solvable problems of SUSY quantum mechanics. It includes all irreducible matrix superpotentials of the generic form W=kQ+\\frac{1}{k} R+P, where k is a variable parameter, Q is the unit matrix multiplied by a real-valued function of independent variable x, and P and R are the Hermitian matrices depending on x. In particular, we recover the Pron'ko-Stroganov 'matrix Coulomb potential' and all known scalar shape invariant potentials of SUSY quantum mechanics. In addition, five new shape invariant potentials are presented. Three of them admit a dual shape invariance, i.e. the related Hamiltonians can be factorized using two non-equivalent superpotentials. We find discrete spectrum and eigenvectors for the corresponding Schrödinger equations and prove that these eigenvectors are normalizable.

  11. Aluminum for plasmonics.

    PubMed

    Knight, Mark W; King, Nicholas S; Liu, Lifei; Everitt, Henry O; Nordlander, Peter; Halas, Naomi J

    2014-01-28

    Unlike silver and gold, aluminum has material properties that enable strong plasmon resonances spanning much of the visible region of the spectrum and into the ultraviolet. This extended response, combined with its natural abundance, low cost, and amenability to manufacturing processes, makes aluminum a highly promising material for commercial applications. Fabricating Al-based nanostructures whose optical properties correspond with theoretical predictions, however, can be a challenge. In this work, the Al plasmon resonance is observed to be remarkably sensitive to the presence of oxide within the metal. For Al nanodisks, we observe that the energy of the plasmon resonance is determined by, and serves as an optical reporter of, the percentage of oxide present within the Al. This understanding paves the way toward the use of aluminum as a low-cost plasmonic material with properties and potential applications similar to those of the coinage metals. PMID:24274662

  12. Regeneration of aluminum hydride

    DOEpatents

    Graetz, Jason Allan; Reilly, James J; Wegrzyn, James E

    2012-09-18

    The present invention provides methods and materials for the formation of hydrogen storage alanes, AlH.sub.x, where x is greater than 0 and less than or equal to 6 at reduced H.sub.2 pressures and temperatures. The methods rely upon reduction of the change in free energy of the reaction between aluminum and molecular H.sub.2. The change in free energy is reduced by lowering the entropy change during the reaction by providing aluminum in a state of high entropy, and by increasing the magnitude of the change in enthalpy of the reaction or combinations thereof.

  13. Regeneration of aluminum hydride

    DOEpatents

    Graetz, Jason Allan; Reilly, James J.

    2009-04-21

    The present invention provides methods and materials for the formation of hydrogen storage alanes, AlH.sub.x, where x is greater than 0 and less than or equal to 6 at reduced H.sub.2 pressures and temperatures. The methods rely upon reduction of the change in free energy of the reaction between aluminum and molecular H.sub.2. The change in free energy is reduced by lowering the entropy change during the reaction by providing aluminum in a state of high entropy, by increasing the magnitude of the change in enthalpy of the reaction or combinations thereof.

  14. Elevated temperature aluminum alloys

    NASA Technical Reports Server (NTRS)

    Meschter, Peter (Inventor); Lederich, Richard J. (Inventor); O'Neal, James E. (Inventor)

    1989-01-01

    Three aluminum-lithium alloys are provided for high performance aircraft structures and engines. All three alloys contain 3 wt % copper, 2 wt % lithium, 1 wt % magnesium, and 0.2 wt % zirconium. Alloy 1 has no further alloying elements. Alloy 2 has the addition of 1 wt % iron and 1 wt % nickel. Alloy 3 has the addition of 1.6 wt % chromium to the shared alloy composition of the three alloys. The balance of the three alloys, except for incidentql impurities, is aluminum. These alloys have low densities and improved strengths at temperatures up to 260.degree. C. for long periods of time.

  15. Aluminum Hydroxide and Magnesium Hydroxide

    MedlinePlus

    Aluminum Hydroxide, Magnesium Hydroxide are antacids used together to relieve heartburn, acid indigestion, and upset stomach. They ... They combine with stomach acid and neutralize it. Aluminum Hydroxide, Magnesium Hydroxide are available without a prescription. ...

  16. [Analysis of tartrazine aluminum lake and sunset yellow aluminum lake in foods by capillary zone electrophoresis].

    PubMed

    Zhang, Yiding; Chang, Cuilan; Guo, Qilei; Cao, Hong; Bai, Yu; Liu, Huwei

    2014-04-01

    A novel analytical method for tartrazine aluminum lake and sunset yellow aluminum lake using capillary zone electrophoresis (CZE) was studied. The pigments contained in the color lakes were successfully separated from the aluminum matrix in the pre-treatment process, which included the following steps: dissolve the color lakes in 0.1 mol/L H2SO4, adjust the pH of the solution to 5.0, then mix it with the solution of EDTA x 2Na and heat it in a water bath, then use polyamide powder as the stationary phase of solid phase extraction to separate the pigments from the solution, and finally elute the pigments with 0.1 mol/L NaOH. The CZE conditions systematically optimized for tartrazine aluminum lake were: 48.50 cm of a fused silica capillary with 40.00 cm effective length and 50 microm i. d., the temperature controlled at 20.0 degrees C, 29.0 kV applied, HPO4(2-)-PO4(3-) (0.015 mol/L, pH 11.45) solution as running buffer, detection at 263 nm. The conditions for sunset yellow aluminum lake were: the same capillary and temperature, 25.0 kV applied, HPO4(2-)-PO4(3-) (0.025 mol/L, pH 11.45) solution as running buffer, detection at 240 nm. The limits of detection were 0.26 mg/L and 0.27 mg/L, and the linear ranges were 0.53-1.3 x 10(2) mg/L and 0.54-1.4 x 10(2) mg/L for tartrazine aluminum lake and sunset yellow aluminum lake, respectively. The RSDs were 4.3% and 5.7% (run to run, n = 6), 5.6% and 6.0% (day to day, n = 6) for tartrazine aluminum lake and sunset yellow aluminum lake, respectively. Further developments for this method could make it a routinely used method analyzing color lakes in foods. PMID:25069336

  17. PROCESS FOR REMOVING ALUMINUM COATINGS

    DOEpatents

    Flox, J.

    1959-07-01

    A process is presented for removing aluminum jackets or cans from uranium slugs. This is accomplished by immersing the aluminum coated uranium slugs in an aqueous solution of 9 to 20% sodium hydroxide and 35 to 12% sodium nitrate to selectively dissolve the aluminum coating, the amount of solution being such as to obtain a molar ratio of sodium hydroxide to aluminum of at least

  18. RECLAMATION OF ALUMINUM FINISHING SLUDGES

    EPA Science Inventory

    The research study of the reclamation of aluminum-anodizing sludges was conducted in two sequential phases focused on enhanced dewatering of aluminum-anodizing sludges to produce commercial-strength solutions of aluminum sulfate, i.e., liquid alum. The use of high-pressure (14 to...

  19. Electrically conductive anodized aluminum coatings

    NASA Technical Reports Server (NTRS)

    Alwitt, Robert S. (Inventor); Liu, Yanming (Inventor)

    2001-01-01

    A process for producing anodized aluminum with enhanced electrical conductivity, comprising anodic oxidation of aluminum alloy substrate, electrolytic deposition of a small amount of metal into the pores of the anodized aluminum, and electrolytic anodic deposition of an electrically conductive oxide, including manganese dioxide, into the pores containing the metal deposit; and the product produced by the process.

  20. High Strength Discontinuously Reinforced Aluminum For Rocket Applications

    NASA Technical Reports Server (NTRS)

    Pandey, A. B.; Shah, S. R.; Shadoan, M.

    2003-01-01

    This study presents results on the development of a new aluminum alloy with very high strength and ductility. Five compositions of Al-Mg-Sc-Gd-Zr alloy were selected for this purpose. These alloys were also reinforced with 15 volume percent silicon-carbide and boron-carbide particles to produce Discontinuously Reinforced Aluminum (DRA) materials. Matrix alloys and DRA were processed using a powder metallurgy process. The helium gas atomization produced very fine powder with cellular-dentritic microstructure. The microstructure of matrix alloys showed fine Al3Sc based precipitate which provides significant strengthening in these alloys. DRA showed uniform distribution of reinforcement in aluminum matrix. DRA materials were tested at -320 F, 75 F in air and 7S F in gaseous hydrogen environments and matrix alloys were tested at 75 F in air. DRA showed high strengths in the range of 89-111 ksi (614-697 MPa) depending on alloy compositions and test environments. Matrix alloys had a good combination of strength, 84-89 ksi (579-621 MPa) and ductility, 4.5-6.5%. The properties of these materials can further be improved by proper control of processing parameters.

  1. Development of Enriched Borated Aluminum Alloy for Basket Material of Cask for Spent Nuclear Fuel

    SciTech Connect

    Katsura Kajihara; Yasuhiro Aruga; Jun Shimojo; Hiroaki Taniuchi; Tsutomu Takeda; Masatosi Sasaki

    2002-07-01

    New enriched borated aluminum alloys manufactured by melting process are developed, which resulted in supplying structural basket materials for spent nuclear fuel packagings. In this process, the borated aluminum alloys were melted in a vacuum induction furnace at elevated temperature than that of ordinary aluminum melting processes. Boron dissolves into the matrix at the temperature of 1273 K or more, and fine aluminum diboride is precipitated and uniformly dispersed upon cooling rapidity. It is confirmed that boron is homogeneously dispersed with the fine particles of approximate 5 in average size in the product. Tensile strength and creep property at elevated temperature in 1 mass-%B 6061-T651 plate and 1 mass-%B 3004 extruded rectangular pipe as structural materials are examined. It is confirmed that the both of borated aluminum alloys have stable strength and creep properties that are similar to those of ordinary aluminum alloys. (authors)

  2. Aluminum battery alloys

    DOEpatents

    Thompson, David S.; Scott, Darwin H.

    1985-01-01

    Aluminum alloys suitable for use as anode structures in electrochemical cs are disclosed. These alloys include iron levels higher than previously felt possible, due to the presence of controlled amounts of manganese, with possible additions of magnesium and controlled amounts of gallium.

  3. Mechanisms of aluminum tolerance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aluminum (Al) toxicity limits agricultural productivity over much of the world’s arable land by inhibiting root growth and development. Affected plants have difficulty in acquiring adequate water and nutrition from their soil environments and thus have stunted shoot development and diminished yield....

  4. Maize aluminum tolerance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize is one of the most economically important food crops grown on acid soils, where aluminum (Al) toxicity greatly limits crop yields. Considerable variation for Al tolerance exists in maize, and this variation has been exploited for many years by plant breeders to enhance maize Al tolerance. Curr...

  5. Aluminum-ferricyanide battery

    SciTech Connect

    Marsh, C.; Licht, S.L.

    1993-11-29

    A battery capable of producing high current densities with high charge capacity is described which includes an aluminum anode, a ferricyanide electrolyte and a second electrode capable of reducing ferricyanide electrolyte which is either dissolved in an alkaline solution or alkaline seawater solution. The performance of the battery is enhanced by high temperature and high electrolyte flow rates.

  6. Aluminum Sulfate 18 Hydrate

    ERIC Educational Resources Information Center

    Young, Jay A.

    2004-01-01

    A chemical laboratory information profile (CLIP) of the chemical, aluminum sulfate 18 hydrate, is presented. The profile lists physical and harmful properties, exposure limits, reactivity risks, and symptoms of major exposure for the benefit of teachers and students using the chemical in the laboratory.

  7. Fluxless aluminum brazing

    DOEpatents

    Werner, W.J.

    1974-01-01

    This invention relates to a fluxless brazing alloy for use in forming brazed composites made from members of aluminum and its alloys. The brazing alloy consists of 35-55% Al, 10--20% Si, 25-60% Ge; 65-88% Al, 2-20% Si, 2--18% In; 65--80% Al, 15-- 25% Si, 5- 15% Y. (0fficial Gazette)

  8. Aluminum battery alloys

    DOEpatents

    Thompson, D.S.; Scott, D.H.

    1984-09-28

    Aluminum alloys suitable for use as anode structures in electrochemical cells are disclosed. These alloys include iron levels higher than previously felt possible, due to the presence of controlled amounts of manganese, with possible additions of magnesium and controlled amounts of gallium.

  9. REMOVAL OF ALUMINUM COATINGS

    DOEpatents

    Peterson, J.H.

    1959-08-25

    A process is presented for dissolving aluminum jackets from uranium fuel elements without attack of the uranium in a boiling nitric acid-mercuric nitrate solution containing up to 50% by weight of nitrtc acid and mercuric nitrate in a concentration of between 0.05 and 1% by weight.

  10. Building an aluminum car

    SciTech Connect

    Ashley, S.

    1994-05-01

    This article examines the increasing use of aluminum in automobiles to decrease weight and consequently increase fuel economy. The topics of the article include federal fuel economy goals, the development of optimum body structure and manufacturing techniques, comparison with steel, cost of materials, weight reduction and recycling of materials.

  11. Mechanical properties of several magnesium and aluminum composites. Final report

    SciTech Connect

    Tsangarakis, N.; Taleghani, B.

    1992-12-01

    Several composites of magnesium and aluminum alloys were tested in order to assess and evaluate their mechanical properties. The magnesium alloys were AZ91 C, ZE41 A, and commercially pure magnesium, reinforced with 40% by volume continuous graphite fiber. The tensile properties of these composites were not superior to those of unreinforced magnesium and estimates of their fracture toughness were low. The matrices of the aluminum composites were 2124-T6, 6061-T4, 2124-T4, and 2219-T4. The reinforcements were either particulate or whiskers of silicon carbide or boron carbide and their volume content was 15% to 30%. The aluminum composites which were reinforced with silicon carbide particulate exhibited improved yield and ultimate tensile stresses, as well as tensile elastic modulus over the unreinforced aluminum alloys. The 2124-T4/B4C/25p composite exhibited the highest ultimate tensile strength which was 511 MPa. The composite which was reinforced with whiskers of silicon carbide exhibited an endurance limit which was 20% higher than that of the matrix alloy. The compressive properties and fracture toughness of some of these aluminum composites were not improved over those of the unreinforced matrix alloy.... Composites, Mechanical properties.

  12. Mechanical properties of some silicon carbide reinforced aluminum composites

    SciTech Connect

    Tsangarakis, N.; Andrews, B.O.; Cavallaro, C.

    1987-05-01

    The mechanical properties of several particulate and continuous fiber silicon carbide-reinforced aluminum composites were examined. The tensile strength of a 47 percent silicon carbide fiber unidirectionally-reinforced aluminum composite was 1273 and 76 MPa parallel and normal to the fiber direction, respectively. The tensile strength of (0 deg/90 deg) 4s and (0/sub 2/90/0)s composites were 629 and 864 MPa, respectively. The tensile properties of a 30 percent silicon carbide particulate reinforced aluminum were found to depend on the chemistry of the metal matrix. The endurance limits of the fiber and the particulate reinforced aluminum were at the most 55 percent and 33 percent of the respective tensile strengths. The fracture toughness of the fiber reinforced composite varied with specimen width, while that of the particulate reinforced composite was 21-29 MPa sq rt m. The fatigue crack growth rate in the latter composite decreased with material thickness. There were indications that the fatigue crack growth rate in the silicon carbide particulate reinforced aluminum may be independent of variations in the chemistry of the metal matrix. 6 references.

  13. Mesoporous aluminum phosphite

    SciTech Connect

    El Haskouri, Jamal; Perez-Cabero, Monica; Guillem, Carmen; Latorre, Julio; Beltran, Aurelio; Beltran, Daniel; Amoros, Pedro

    2009-08-15

    High surface area pure mesoporous aluminum-phosphorus oxide-based derivatives have been synthesized through an S{sup +}I{sup -} surfactant-assisted cooperative mechanism by means of a one-pot preparative procedure from aqueous solution and starting from aluminum atrane complexes and phosphoric and/or phosphorous acids. A soft chemical extraction procedure allows opening the pore system of the parent as-prepared materials by exchanging the surfactant without mesostructure collapse. The nature of the pore wall can be modulated from mesoporous aluminum phosphate (ALPO) up to total incorporation of phosphite entities (mesoporous aluminum phosphite), which results in a gradual evolution of the acidic properties of the final materials. While phosphate groups in ALPO act as network building blocks (bridging Al atoms), the phosphite entities become basically attached to the pore surface, what gives practically empty channels. The mesoporous nature of the final materials is confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and N{sub 2} adsorption-desorption isotherms. The materials present regular unimodal pore systems whose order decreases as the phosphite content increases. NMR spectroscopic results confirm the incorporation of oxo-phosphorus entities to the framework of these materials and also provide us useful information concerning the mechanism through which they are formed. - Abstract: TEM image of the mesoporous aluminum phosphite showing the hexagonal disordered pore array that is generated by using surfactant micelles as template. Also a scheme emphasizing the presence of an alumina-rich core and an ALPO-like pore surface is presented.

  14. SOLDERING OF ALUMINUM BASE METALS

    DOEpatents

    Erickson, G.F.

    1958-02-25

    This patent deals with the soldering of aluminum to metals of different types, such as copper, brass, and iron. This is accomplished by heating the aluminum metal to be soldered to slightly above 30 deg C, rubbing a small amount of metallic gallium into the part of the surface to be soldered, whereby an aluminum--gallium alloy forms on the surface, and then heating the aluminum piece to the melting point of lead--tin soft solder, applying lead--tin soft solder to this alloyed surface, and combining the aluminum with the other metal to which it is to be soldered.

  15. Regenerator matrix physical property data

    NASA Technical Reports Server (NTRS)

    Fucinari, C. A.

    1980-01-01

    Among several cellular ceramic structures manufactured by various suppliers for regenerator application in a gas turbine engine, three have the best potential for achieving durability and performance objectives for use in gas turbines, Stirling engines, and waste heat recovery systems: (1) an aluminum-silicate sinusoidal flow passage made from a corrugated wate paper process; (2) an extruded isosceles triangle flow passage; and (3) a second generation matrix incorporating a square flow passage formed by an embossing process. Key physical and thermal property data for these configurations presented include: heat transfer and pressure drop characteristics, compressive strength, tensile strength and elasticity, thermal expansion characteristics, chanical attack, and thermal stability.

  16. Evidence of sub-10 nm aluminum-oxygen precipitates in silicon.

    PubMed

    Moutanabbir, Oussama; Isheim, Dieter; Mao, Zugang; Seidman, David N

    2016-05-20

    In this research, ultraviolet laser-assisted atom-probe tomography (APT) was utilized to investigate precisely the behavior at the atomistic level of aluminum impurities in ultrathin epitaxial silicon layers. Aluminum atoms were incorporated in situ during the growth process. The measured average aluminum concentration in the grown layers exceeds by several orders of magnitude the equilibrium bulk solubility. Three-dimensional atom-by-atom mapping demonstrates that aluminum atoms precipitate in the silicon matrix and form nanoscopic precipitates with lateral dimensions in the 1.3 to 6.2 nm range. These precipitates were found to form only in the presence of oxygen impurity atoms, thus providing clear evidence of the longhypothesized role of oxygen and aluminum-oxygen complexes in facilitating the precipitation of aluminum in a silicon lattice. The measured average aluminum and oxygen concentrations in the precipitates are ∼10 ± 0.5 at.% and ∼4.4 ± 0.5 at.%, respectively. This synergistic interaction is supported by first-principles calculations of the binding energies of aluminum-oxygen dimers in silicon. The calculations demonstrate that there is a strong binding between aluminum and oxygen atoms, with Al-O-Al and O-Al-Al as the energetically favorable sequences corresponding to precipitates in which the concentration of aluminum is twice as large as the oxygen concentration in agreement with APT data. PMID:27071742

  17. Evidence of sub-10 nm aluminum-oxygen precipitates in silicon

    NASA Astrophysics Data System (ADS)

    Moutanabbir, Oussama; Isheim, Dieter; Mao, Zugang; Seidman, David N.

    2016-05-01

    In this research, ultraviolet laser-assisted atom-probe tomography (APT) was utilized to investigate precisely the behavior at the atomistic level of aluminum impurities in ultrathin epitaxial silicon layers. Aluminum atoms were incorporated in situ during the growth process. The measured average aluminum concentration in the grown layers exceeds by several orders of magnitude the equilibrium bulk solubility. Three-dimensional atom-by-atom mapping demonstrates that aluminum atoms precipitate in the silicon matrix and form nanoscopic precipitates with lateral dimensions in the 1.3 to 6.2 nm range. These precipitates were found to form only in the presence of oxygen impurity atoms, thus providing clear evidence of the long-hypothesized role of oxygen and aluminum-oxygen complexes in facilitating the precipitation of aluminum in a silicon lattice. The measured average aluminum and oxygen concentrations in the precipitates are ∼10 ± 0.5 at.% and ∼4.4 ± 0.5 at.%, respectively. This synergistic interaction is supported by first-principles calculations of the binding energies of aluminum-oxygen dimers in silicon. The calculations demonstrate that there is a strong binding between aluminum and oxygen atoms, with Al-O-Al and O-Al-Al as the energetically favorable sequences corresponding to precipitates in which the concentration of aluminum is twice as large as the oxygen concentration in agreement with APT data.

  18. Sync Matrix

    2004-12-31

    Sync Matrix provides a graphic display of the relationships among all of the response activities of each jurisdiction. This is accomplished through software that organizes and displays the activities by jurisdiction, function, and time for easy review and analysis. The software can also integrate the displays of multiple jurisdictions to allow examination of the total response.

  19. Environment enhanced fatigue of advanced aluminum alloys and composites

    NASA Technical Reports Server (NTRS)

    Slavik, Donald C.; Gangloff, Richard P.

    1990-01-01

    The objective is to characterize and understand the environmental fatigue crack propagation behavior of advanced, high stiffness and strength, aluminum alloys and metal matrix composites. Those gases and aqueous electrolytes which are capable of producing atomic hydrogen by reactions on clean crack surfaces are emphasized. Characterizations of the behavior of new materials are sought to provide data for damage tolerant component life prediction. Mechanistic models are sought for crack tip damage processes which are generally applicable to structural aluminum alloys. Such models will enable predictions of cracking behavior outside of the data, metallurgical improvements in material cracking resistance, and insight on hydrogen compatibility.

  20. A comparison of ASTROMAG coils made with aluminum and copper based superconductor

    NASA Technical Reports Server (NTRS)

    Green, M. A.

    1991-01-01

    The use of an aluminum matrix superconductor in the coils for the ASTROMAG magnet will increase the integrated field for conducting particle astrophysics experiments in space as compared to equal mass coils made with a copper matrix superconductor. The increased ability to detect charged particles can be achieved without decreasing the current margin of the superconductor in the coils. The use of a low-resistivity aluminum matrix conductor increases the energy needed to initiate a quench by two orders or magnitude. The current decay time constant during a quench is substantially increased. As a result, the quench energy dumped into the helium tank is reduced (the ASTROMAG coils are thermally decoupled from the helium tank), and the forces on the shield and shells due to eddy currents will be lower. A description is also given of the problems associated with the use of an aluminum matrix superconductor in the coils.

  1. Tensile and compressive test results for metal matrix composites

    NASA Technical Reports Server (NTRS)

    Shuart, M. J.; Herakovich, C. T.

    1977-01-01

    Experimental results of the mechanical behavior of two metal matrix composite systems at room temperature are presented. Ultimate stress, ultimate strain, Poisson's ratio, and initial Young's Modulus are documented for BORSIC/Aluminum in uniaxial tension and Boron/Aluminum in uniaxial tension and compression. Poisson's ratio is used for nonlinear stress-strain behavior. A comparison of compression results for B/Al as obtained from sandwich beam compression specimens and IITRI coupon compression specimens is presented.

  2. Aluminum permanganate battery

    SciTech Connect

    Marsh, C.; Licht, S.L.

    1993-11-30

    A battery is provided comprising an aluminum anode, an aqueous solution of permanganate as the cathodic species and a second electrode capable of reducing permanganate. Such a battery system is characterized by its high energy density and low polarization losses when operating at high temperatures in a strong caustic electrolyte, i.e., high concentration of hydroxyl ions. A variety of anode and electrocatalyst materials are suitable for the efficient oxidation-reduction process and are elucidated.

  3. Aluminum microstructures on anodic alumina for aluminum wiring boards.

    PubMed

    Jha, Himendra; Kikuchi, Tatsuya; Sakairi, Masatoshi; Takahashi, Hideaki

    2010-03-01

    The paper demonstrates simple methods for the fabrication of aluminum microstructures on the anodic oxide film of aluminum. The aluminum sheets were first engraved (patterned) either by laser beam or by embossing to form deep grooves on the surface. One side of the sheet was then anodized, blocking the other side by using polymer mask to form the anodic alumina. Because of the lower thickness at the bottom part of the grooves, the part was completely anodized before the complete oxidation of the other parts. Such selectively complete anodizing resulted in the patterns of metallic aluminum on anodic alumina. Using the technique, we fabricated microstructures such as line patterns and a simple wiring circuit-board-like structure on the anodic alumina. The aluminum microstructures fabricated by the techniques were embedded in anodic alumina/aluminum sheet, and this technique is promising for applications in electronic packaging and devices. PMID:20356280

  4. Particle denuded zones in alumina reinforced aluminum matrix composite weldments

    SciTech Connect

    Chidambaram, A.; Bhole, S.D.

    1996-08-01

    The Welding Institute of Canada (WIC), Ontario, has been studying the weldability of different DURALCAN MMC`s. Research on alumina reinforced (20 vol.%) 6061 Al alloy GTA welds showed satisfactory tensile and yield strengths (0.2% Proof Stress) but the welds failed to pass the bend test requirements with fracture taking place in the relatively brittle heat affected zone (HAZ). Further, the welds were characterized by a region which was devoid of reinforcement particles adjacent to the fusion lines. The present study was undertaken to try and explain the formation of this particle denuded zone (PDZ) at the fusion lines.

  5. Metal Compression Forming of aluminum alloys and metal matrix composites

    SciTech Connect

    Viswanathan, S.; Ren, W.; Porter, W.D.; Brinkman, C.R.; Sabau, A.S.; Purgert, R.M.

    2000-02-01

    Metal Compression Forming (MCF) is a variant of the squeeze casting process, in which molten metal is allowed to solidify under pressure in order to close porosity and form a sound part. However, the MCF process applies pressure on the entire mold face, thereby directing pressure on all regions of the casting and producing a uniformly sound part. The process is capable of producing parts with properties close to those of forgings, while retaining the near net shape, complexity in geometry, and relatively low cost of the casting process.

  6. Corrosion Mechanisms of Steel and Cast Iron by Molten Aluminum

    NASA Astrophysics Data System (ADS)

    Balloy, David; Tissier, Jean-Charles; Giorgi, Marie-Laurence; Briant, Marc

    2010-09-01

    The corrosion mechanisms by liquid aluminum of three industrial materials have been studied: unalloyed steel (UAS), and ferritic and modified pearlitic cast irons (FCI and PCI, respectively). The behavior of these materials when in contact with liquid aluminum is different. Aluminum diffuses deep into the UAS and forms intermetallic compounds with iron at the surface and in the steel matrix. At the surface, only Fe2Al5 and FeAl3 are found. In the matrix, FeAl2 also is formed in agreement with the equilibrium Fe-Al diagram. From the matrix to FeAl2, the Al content in the ferrite increases progressively until Al saturation is reached. At this step, black elongated precipitates (Al4C3 and/or graphite) appear. Graphite lamellas present in both FCI and PCI constitute an efficient barrier to the Al diffusion. The high silicon content of the FCI leads to the formation of a phase free from Al and saturated in Si. For the PCI, a thin layer rich in Al and Si, which is formed between the matrix and Fe2Al5, limits the diffusion of atoms. The effects of Cr and P added in the PCI also are discussed.

  7. Aluminum Carbothermic Technology

    SciTech Connect

    Bruno, Marshall J.

    2005-03-31

    This report documents the non-proprietary research and development conducted on the Aluminum Carbothermic Technology (ACT) project from contract inception on July 01, 2000 to termination on December 31, 2004. The objectives of the program were to demonstrate the technical and economic feasibility of a new carbothermic process for producing commercial grade aluminum, designated as the ''Advanced Reactor Process'' (ARP). The scope of the program ranged from fundamental research through small scale laboratory experiments (65 kW power input) to larger scale test modules at up to 1600 kW power input. The tasks included work on four components of the process, Stages 1 and 2 of the reactor, vapor recovery and metal alloy decarbonization; development of computer models; and economic analyses of capital and operating costs. Justification for developing a new, carbothermic route to aluminum production is defined by the potential benefits in reduced energy, lower costs and more favorable environmental characteristics than the conventional Hall-Heroult process presently used by the industry. The estimated metrics for these advantages include energy rates at approximately 10 kWh/kg Al (versus over 13 kWh/kg Al for Hall-Heroult), capital costs as low as $1250 per MTY (versus 4,000 per MTY for Hall-Heroult), operating cost reductions of over 10%, and up to 37% reduction in CO2 emissions for fossil-fuel power plants. Realization of these benefits would be critical to sustaining the US aluminum industries position as a global leader in primary aluminum production. One very attractive incentive for ARP is its perceived ability to cost effectively produce metal over a range of smelter sizes, not feasible for Hall-Heroult plants which must be large, 240,000 TPY or more, to be economical. Lower capacity stand alone carbothermic smelters could be utilized to supply molten metal at fabrication facilities similar to the mini-mill concept employed by the steel industry. Major

  8. Extracting aluminum from dross tailings

    NASA Astrophysics Data System (ADS)

    Amer, A. M.

    2002-11-01

    Aluminum dross tailings, an industrial waste, from the Egyptian Aluminium Company (Egyptalum) was used to produce two types of alums: aluminum-sulfate alum [itAl2(SO4)3.12H2O] and ammonium-aluminum alum [ (NH 4)2SO4AL2(SO4)3.24H2O]. This was carried out in two processes. The first process is leaching the impurities using diluted H2SO4 with different solid/liquid ratios at different temperatures to dissolve the impurities present in the starting material in the form of solute sulfates. The second process is the extraction of aluminum (as aluminum sulfate) from the purifi ed aluminum dross tailings thus produced. The effects of temperature, time of reaction, and acid concentration on leaching and extraction processes were studied. The product alums were analyzed using x-ray diffraction and thermal analysis techniques.

  9. Structure and properties of porous ceramics obtained from aluminum hydroxide

    NASA Astrophysics Data System (ADS)

    Levkov, R.; Kulkov, S.

    2016-08-01

    In this paper the study of porous ceramics obtained from aluminum hydroxide with gibbsite modification is presented. The dependence of porosity and mechanical characteristics of the material sintered at different temperatures was studied. It was shown that compressive strength of alumina ceramics increases by 40 times with decreasing the pore volume from 65 to 15%. It was shown that aluminum hydroxide may be used for pore formation and pore volume in the sintered ceramics can be controlled by varying the aluminum hydroxide concentration and sintering temperature. Based on these results one can conclude that the obtained structure is very close to inorganic bone matrix and can be used as promising material for bone implants production.

  10. Refractory Characteristics of Aluminum Dross-Kaolin Composite

    NASA Astrophysics Data System (ADS)

    Adeosun, S. O.; Akpan, E. I.; Dada, M. O.

    2014-11-01

    The suitability of using aluminum dross waste and kaolin to produce refractory bricks is experimentally studied. Thirty brick samples of different blends are produced, dried at 30°C, dried further at 110°C, and fired at 1200°C. The firing temperature point, bulk density, apparent porosity, thermal conductivity, thermal shock, loss on ignition, permeability, shatter index, and shrinkage of the bricks blends are determined. The results show that some blend samples have good refractory characteristics with mixing ratio 4:1:2 (representing weight in grams of aluminum dross, plastic clay, and kaolin, respectively). The evaluations of studied properties reveal the possibility for aluminum dross waste to be used as matrix in refractory bricks.

  11. MICROSTRUCTURE EVOLUTION MODELING FOR SOLUTION TREATMENT OF ALUMINUM ALLOYS

    SciTech Connect

    Yin, Hebi; Sabau, Adrian S; Skszek, Timothy; Niu, X

    2013-01-01

    The microstructure evolution during solution treatment plays an important role in mechanical properties of heat-treated aluminum alloys. In this paper, models were reviewed that can predict the microstructure evolution during the solutionizing process of the aging heat treatment of aluminum alloys. The dissolution of Mg2Si particles has been modeled as a diffusion process of Mg in the -Al matrix. The evolution of volumetric fraction of fragmented silicon as a function of time and temperature was also considered. The growth and coarsening of silicon particles during the heat treatment was considered. It was found that constitutive equations and required property data for most of the phenomena that need to be considered are available. Several model parameters that need to be obtained from material characterization were identified. Pending the availability of these model parameters, this comprehensive model can be used to describe the microstructure evolution of aluminum alloys in order to optimize the solutionizing heat treatment for energy savings.

  12. 21 CFR 73.1645 - Aluminum powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Aluminum powder. 73.1645 Section 73.1645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1645 Aluminum powder. (a) Identity. (1) The color additive aluminum powder shall be composed of finely divided particles of aluminum prepared from virgin aluminum....

  13. 21 CFR 73.1645 - Aluminum powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Aluminum powder. 73.1645 Section 73.1645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1645 Aluminum powder. (a) Identity. (1) The color additive aluminum powder shall be composed of finely divided particles of aluminum prepared from virgin aluminum....

  14. 21 CFR 73.1645 - Aluminum powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Aluminum powder. 73.1645 Section 73.1645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1645 Aluminum powder. (a) Identity. (1) The color additive aluminum powder shall be composed of finely divided particles of aluminum prepared from virgin aluminum....

  15. 21 CFR 73.1645 - Aluminum powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Aluminum powder. 73.1645 Section 73.1645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1645 Aluminum powder. (a) Identity. (1) The color additive aluminum powder shall be composed of finely divided particles of aluminum prepared from virgin aluminum....

  16. 21 CFR 73.1645 - Aluminum powder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Aluminum powder. 73.1645 Section 73.1645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1645 Aluminum powder. (a) Identity. (1) The color additive aluminum powder shall be composed of finely divided particles of aluminum prepared from virgin aluminum....

  17. Effects of Initial Temper Condition and Postweld Heat Treatment on the Properties of Dissimilar Friction-Stir-Welded Joints between AA7075 and AA6061 Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    İpekoğlu, Güven; Çam, Gürel

    2014-06-01

    In this study, dissimilar AA7075-O/6061-O and AA7075-T6/6061-T6 butt joints were produced by friction stir welding (FSW), and postweld heat treatment (PWHT) was applied to the joints obtained. The effects of initial temper condition and PWHT on the microstructure and mechanical properties of the dissimilar joints were thus investigated. It was demonstrated that sound dissimilar joints can be produced for both temper conditions. A hardness increase in the joint area ( i.e., strength overmatching) was obtained in the joints produced in the O-temper condition, whereas a hardness loss was observed in the joint area of the joints obtained in the T6 temper condition. It was also well demonstrated that PWHT could be used in order to improve the joint properties for both O and T6 joints provided that the joint is defect-free prior to subsequent heat treatment.

  18. The young's modulus of 1018 steel and 67061-T6 aluminum measured from quasi-static to elastic precursor strain-rates

    SciTech Connect

    Rae, Philip J; Trujillo, Carl; Lovato, Manuel

    2009-01-01

    The assumption that Young's modulus is strain-rate invariant is tested for 6061-T6 aluminium alloy and 1018 steel over 10 decades of strain-rate. For the same billets of material, 3 quasi-static strain-rates are investigated with foil strain gauges at room temperature. The ultrasonic sound speeds are measured and used to calculate the moduli at approximately 10{sup 4} s{sup -1}. Finally, ID plate impact is used to generate an elastic pre-cursor in the alloys at a strain-rate of approximately 10{sup 6} s{sup -1} from which the longitudinal sound speed may be obtained. It is found that indeed the Young's modulus is strain-rate independent within the experimental accuracy.

  19. Cathodic phenomena in aluminum electrowinning

    NASA Astrophysics Data System (ADS)

    Bouteillon, J.; Poignet, J. C.; Rameau, J. J.

    1993-02-01

    Although aluminum is one of the world's highest production-volume primary metals, it is particularly costly to produce for a variety of factors, not the least of which are the expenses associated with electrolytic reduction. Based on the scale of global aluminum processing, even minor improvements in the electrowinning technology can result in significant savings of resources. Thus, from this perspective, the following reviews recent studies of cathodic phenomena in aluminum electrowinning.

  20. Laser welding of aluminum alloys

    SciTech Connect

    Leong, K.H.; Sabo, K.R.; Sanders, P.G.; Spawr, W.J.

    1997-03-01

    Recent interest in reducing the weight of automobiles to increase fuel mileage has focused attention on the use of aluminum and associated joining technologies. Laser beam welding is one of the more promising methods for high speed welding of aluminum. Consequently, substantial effort has been expended in attempting to develop a robust laser beam welding process. Early results have not been very consistent in the process requirements but more definitive data has been produced recently. This paper reviews the process parameters needed to obtain consistent laser welds on 5,000 series aluminum alloys and discusses the research necessary to make laser processing of aluminum a reality for automotive applications.

  1. Mineral of the month: aluminum

    USGS Publications Warehouse

    Plunkert, Patricia A.

    2005-01-01

    Aluminum is the second most abundant metallic element in Earth’s crust after silicon. Even so, it is a comparatively new industrial metal that has been produced in commercial quantities for little more than 100 years. Aluminum is lightweight, ductile, malleable and corrosion resistant, and is a good conductor of heat and electricity. Weighing about one-third as much as steel or copper per unit of volume, aluminum is used more than any other metal except iron. Aluminum can be fabricated into desired forms and shapes by every major metalworking technique to add to its versatility.

  2. Characterization of the dimensional stability of advanced metallic materials using an optical test bench structure

    NASA Technical Reports Server (NTRS)

    Hsieh, Cheng; O'Donnell, Timothy P.

    1991-01-01

    The dimensional stability of low-density high specific-strength metal-matrix composites (including 30 vol pct SiC(p)/SXA 24-T6 Al, 25 vol pct SiC(p)/6061-T6 Al, 40 vol pct graphite P100 fiber/6061 Al, 50 vol pct graphite P100 fiber/6061 Al, and 40 vol pct P100 graphite fiber/AZ91D Mg composites) and an Al-Li-Mg metal alloy was evaluated using a specially designed five-strut optical test bench structure. The structure had 30 thermocouple locations, one retroreflector, one linear interferometer multilayer insulation, and various strip heaters. It was placed in a 10 exp -7 torr capability vacuum chamber with a laser head positioned at a window port, and a laser interferometer system for collecting dimensional change data. It was found that composite materials have greater 40-C temporal dimensional stability than the AL-Li-Mg alloy. Aluminum-based composites demonstrated better 40-C temporal stability than Mg-based composites.

  3. Dynamic Properties of Polyurea 1000

    NASA Astrophysics Data System (ADS)

    Mock, W., Jr.; Bartyczak, S.; Lee, G.; Fedderly, J.; Jordan, K.

    2009-06-01

    A gas gun has been used to investigate the shock response of the viscoelastic material Versathane P1000. This polyurea material is synthesized from a polyamine (Versalink P1000, Air Products) with a multi-functional isocyanate (Isonate 143L, Dow Chemical). Versalink P1000 has a nominal molecular weight of 1000. The morphology of the resulting polymer consists of aromatic hard segments in an aliphatic soft-segment elastic matrix. Sabots carrying 9.5-mm-thick metal disks were launched into target assemblies containing the polyurea material. A target assembly consisted of a three-layer sandwich configuration: a 0.9-mm-thick metal disk on the impact side, a 6.5-mm-thick polyurea disk, and a 9.5-mm-thick metal backup disk. The metal disks were either OFHC copper or 6061-T6 aluminum. Impact velocities ranged from 280 to 920 m/s. Impact planarity was 1 milliradian or less. Thin film 50-ohm manganin gauges (Dynasen) were epoxied between the metal/polymer and polymer/metal interfaces in each target assembly to measure the interface stresses as a function of time. The polyurea shock velocity was also determined for each experiment. Measured longitudinal stresses ranged from 5 to 45 kbar. A comparison of the measured initial stress values and calculated pressure values suggests that the shear strength increases with increasing stress.

  4. Production of aluminum metal by electrolysis of aluminum sulfide

    DOEpatents

    Minh, N.Q.; Loutfy, R.O.; Yao, N.P.

    1982-04-01

    Metallic aluminum may be produced by the electrolysis of Al/sub 2/S/sub 3/ at 700 to 800/sup 0/C in a chloride melt composed of one or more alkali metal chlorides, and one or more alkaline earth metal chlorides and/or aluminum chloride to provide improved operating characteristics of the process.

  5. Production of aluminum metal by electrolysis of aluminum sulfide

    DOEpatents

    Minh, Nguyen Q.; Loutfy, Raouf O.; Yao, Neng-Ping

    1984-01-01

    Production of metallic aluminum by the electrolysis of Al.sub.2 S.sub.3 at 700.degree.-800.degree. C. in a chloride melt composed of one or more alkali metal chlorides, and one or more alkaline earth metal chlorides and/or aluminum chloride to provide improved operating characteristics of the process.

  6. Critical properties of aluminum.

    PubMed

    Bhatt, Divesh; Jasper, Ahren W; Schultz, Nathan E; Siepmann, J Ilja; Truhlar, Donald G

    2006-04-01

    Gibbs ensemble Monte Carlo calculations are performed using a validated embedded-atom potential to obtain the vapor-liquid coexistence curve for elemental aluminum in good agreement with available experimental data up to the boiling point. These calculations are then extended to make a reliable prediction of the critical temperature, pressure, and density of Al, which have previously been known only with very large uncertainties. This demonstrates the ability of modern simulations to predict fundamental physical properties that are extremely difficult to measure directly. PMID:16568986

  7. Elevated temperature properties of boron/aluminum composites

    NASA Technical Reports Server (NTRS)

    Sullivan, P. G.

    1978-01-01

    The high temperature properties of boron/aluminum composites, fabricated by an air diffusion bonding technique utilizing vacuum-bonded monolayer tape are reported. Seventeen different combinations of matrix alloy, reinforcement diameter, reinforcement volume percent, angle-ply and matrix enhancement (i.e. titanium cladding and interleaves) were fabricated, inspected, and tested. It is shown that good to excellent mechanical properties could be obtained for air-bonded boron/aluminum composites and that these properties did not decrease significantly up to a test temperature of at least 260 C. Composites made with 8 mil B/W fiber show a much greater longitudinal strength dependence on volume percent fiber than composites made with 5.6 mil fiber. The addition of titanium caused difficulties in composite bonding and yielded composites with reduced strength.

  8. Selective Adsorption of Sodium Aluminum Fluoride Salts from Molten Aluminum

    SciTech Connect

    Leonard S. Aubrey; Christine A. Boyle; Eddie M. Williams; David H. DeYoung; Dawid D. Smith; Feng Chi

    2007-08-16

    Aluminum is produced in electrolytic reduction cells where alumina feedstock is dissolved in molten cryolite (sodium aluminum fluoride) along with aluminum and calcium fluorides. The dissolved alumina is then reduced by electrolysis and the molten aluminum separates to the bottom of the cell. The reduction cell is periodically tapped to remove the molten aluminum. During the tapping process, some of the molten electrolyte (commonly referred as “bath” in the aluminum industry) is carried over with the molten aluminum and into the transfer crucible. The carryover of molten bath into the holding furnace can create significant operational problems in aluminum cast houses. Bath carryover can result in several problems. The most troublesome problem is sodium and calcium pickup in magnesium-bearing alloys. Magnesium alloying additions can result in Mg-Na and Mg-Ca exchange reactions with the molten bath, which results in the undesirable pickup of elemental sodium and calcium. This final report presents the findings of a project to evaluate removal of molten bath using a new and novel micro-porous filter media. The theory of selective adsorption or removal is based on interfacial surface energy differences of molten aluminum and bath on the micro-porous filter structure. This report describes the theory of the selective adsorption-filtration process, the development of suitable micro-porous filter media, and the operational results obtained with a micro-porous bed filtration system. The micro-porous filter media was found to very effectively remove molten sodium aluminum fluoride bath by the selective adsorption-filtration mechanism.

  9. The processing and properties of discontinuously reinforced aluminum composites

    SciTech Connect

    Geiger, A.L.; Walker, J.A. )

    1991-08-01

    Discontinuously-reinforced aluminum (DRA) SiC whisker or particle-reinforced Al-alloy matrix composites produced by P/M methods have progressed toward commercial applications, supported by growing data bases and large-scale production facilities. Attention is presently given to the elastic modulus, plastic, ductile, and toughness characteristics of representative DRA formulations, as well as to the DRAs commercially available in the forms of sheets, extrusions, and optical and instrument grade structures able to supplant beryllium. 36 refs.

  10. Kinetics of aluminum lithium alloys

    NASA Astrophysics Data System (ADS)

    Pletcher, Ben A.

    2009-12-01

    Aluminum lithium alloys are increasingly used in aerospace for their high strength-to-weight ratio. Additions of lithium, up to 4.2 wt% decrease the alloy density while increasing the modulus and yield strength. The metastable, second phase Al3Li or delta' is intriguing, as it remains spherical and coherent with the matrix phase, alpha, well into the overaged condition. Small interfacial strain energy allows these precipitates to remain spherical for volume fractions (VV ) of delta' less than 0.3, making this alloy system ideal for investigation of late-stage coarsening phenomena. Experimental characterization of three binary Al-Li alloys are presented as a critical test of diffusion screening theory and multi-particle diffusion simulations. Quantitative transmission electron microscopy is used to image the precipitates directly using the centered dark-field technique. Images are analyzed autonomously within a novel Matlab function that determines the center and size of each precipitate. Particle size distribution, particle growth kinetics, and maximum particle size are used to track the precipitate growth and correlate with the predictions of screening theory and multi-particle diffusion simulations. This project is the first extensive study of Al-Li alloys, in over 25 years, applying modern transmission electron microscopy and image analysis techniques. Previous studies sampled but a single alloy composition, and measured far fewer precipitates. This study investigates 3 alloys with volume fractions of the delta precipitates, VV =0.1-0.27, aged at 225C for 1 to 10 days. More than 1000 precipitates were sampled per aging time, creating more statistically significant data. Experimental results are used to test the predictions based on diffusion screening theory and multi-particle aging simulations. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)

  11. Aluminum Nanoholes for Optical Biosensing.

    PubMed

    Barrios, Carlos Angulo; Canalejas-Tejero, Víctor; Herranz, Sonia; Urraca, Javier; Moreno-Bondi, María Cruz; Avella-Oliver, Miquel; Maquieira, Ángel; Puchades, Rosa

    2015-01-01

    Sub-wavelength diameter holes in thin metal layers can exhibit remarkable optical features that make them highly suitable for (bio)sensing applications. Either as efficient light scattering centers for surface plasmon excitation or metal-clad optical waveguides, they are able to form strongly localized optical fields that can effectively interact with biomolecules and/or nanoparticles on the nanoscale. As the metal of choice, aluminum exhibits good optical and electrical properties, is easy to manufacture and process and, unlike gold and silver, its low cost makes it very promising for commercial applications. However, aluminum has been scarcely used for biosensing purposes due to corrosion and pitting issues. In this short review, we show our recent achievements on aluminum nanohole platforms for (bio)sensing. These include a method to circumvent aluminum degradation--which has been successfully applied to the demonstration of aluminum nanohole array (NHA) immunosensors based on both, glass and polycarbonate compact discs supports--the use of aluminum nanoholes operating as optical waveguides for synthesizing submicron-sized molecularly imprinted polymers by local photopolymerization, and a technique for fabricating transferable aluminum NHAs onto flexible pressure-sensitive adhesive tapes, which could facilitate the development of a wearable technology based on aluminum NHAs. PMID:26184330

  12. The Benefits of Aluminum Windows.

    ERIC Educational Resources Information Center

    Goyal, R. C.

    2002-01-01

    Discusses benefits of aluminum windows for college construction and renovation projects, including that aluminum is the most successfully recycled material, that it meets architectural glass deflection standards, that it has positive thermal energy performance, and that it is a preferred exterior surface. (EV)

  13. Primary Aluminum Plants Worldwide - 1998

    USGS Publications Warehouse

    1999-01-01

    The 1990 U.S. Bureau of Mines publication, Primary Aluminum Plants Worldwide, has been updated and is now available. The 1998 USGS edition of Primary Aluminum Plants Worldwide is published in two parts. Part I—Detail contains information on individual primary smelter capacity, location, ownership, sources of energy, and other miscellaneous information. Part II—Summary summarizes the capacity data by country

  14. Lost-Soap Aluminum Casting.

    ERIC Educational Resources Information Center

    Mihalow, Paula

    1980-01-01

    Lost-wax casting in sterling silver is a costly experience for the average high school student. However, this jewelry process can be learned at no cost if scrap aluminum is used instead of silver, and soap bars are used instead of wax. This lost-soap aluminum casting process is described. (Author/KC)

  15. Boron carbide-aluminum cermets

    SciTech Connect

    Halverson, D.C.

    1986-09-03

    We have developed boron carbide-aluminum cermets by means of thermodynamic, kinetic, and processing studies. Our research indicates that boron carbide-aluminum cermets offer ''tailorable'' microstructures with designable properties through process control. This new class of cermets has the potential to become a very important material with wide industrial applications.

  16. Aluminum Nanoholes for Optical Biosensing

    PubMed Central

    Barrios, Carlos Angulo; Canalejas-Tejero, Víctor; Herranz, Sonia; Urraca, Javier; Moreno-Bondi, María Cruz; Avella-Oliver, Miquel; Maquieira, Ángel; Puchades, Rosa

    2015-01-01

    Sub-wavelength diameter holes in thin metal layers can exhibit remarkable optical features that make them highly suitable for (bio)sensing applications. Either as efficient light scattering centers for surface plasmon excitation or metal-clad optical waveguides, they are able to form strongly localized optical fields that can effectively interact with biomolecules and/or nanoparticles on the nanoscale. As the metal of choice, aluminum exhibits good optical and electrical properties, is easy to manufacture and process and, unlike gold and silver, its low cost makes it very promising for commercial applications. However, aluminum has been scarcely used for biosensing purposes due to corrosion and pitting issues. In this short review, we show our recent achievements on aluminum nanohole platforms for (bio)sensing. These include a method to circumvent aluminum degradation—which has been successfully applied to the demonstration of aluminum nanohole array (NHA) immunosensors based on both, glass and polycarbonate compact discs supports—the use of aluminum nanoholes operating as optical waveguides for synthesizing submicron-sized molecularly imprinted polymers by local photopolymerization, and a technique for fabricating transferable aluminum NHAs onto flexible pressure-sensitive adhesive tapes, which could facilitate the development of a wearable technology based on aluminum NHAs. PMID:26184330

  17. Channeling of aluminum in silicon

    SciTech Connect

    Wilson, R.G.; Hopkins, C.G.

    1985-05-15

    A systematic study of channeling of aluminum in the silicon crystal is reported. Depth distributions measured by secondary ion mass spectrometry are reported for 40-, 75-, and 150-keV aluminum channeled in the <100> and <110> directions of silicon. The profile dependence on alignment angle is shown for 150-keV aluminum in the <110> of silicon. Aluminum has low electronic stopping in silicon and corresponding deep channeled profiles are observed for aligned implants and deep channeling tails are observed on random implants. The maximum channeling range for 150-keV Al in <100> silicon is about 2.8 ..mu..m and is about 6.4 ..mu..m in <110> silicon. Some ions will reach the maximum channeling range even for 2/sup 0/ misalignment. Many of the deep channeling tails and ''supertails'' reported in earlier literature can be explained by the normal channeling of aluminum in silicon.

  18. Numerical simulation of damage progression in unidirectional composites

    NASA Astrophysics Data System (ADS)

    Chung, Michael

    1997-11-01

    The damage growth in unidirectional composite materials is a complex evolutionary process. The initiation, growth and interaction of these damage mechanisms are strongly influenced by the properties of the constituent materials. In addition, thermal residual stresses are usually induced in composite material during the curing process. Therefore it is essential to consider the effect of the properties of the constituent materials and thermal residual stresses on the fracture behavior of composite materials. In this study, a computational methodology that employs a hybrid micromechanical-anisotropic continuum model developed previously to simulate the damage growth on the constituent level of composite materials has been modified and extended to include the effect of temperature change. The unique features of this methodology is that multiple modes of damage can be simulated simultaneously, and the direction of damage growth, in the form of a crack path, needs not be pre-selected. More specifically, the methodology uses a special purpose finite element program, PSEUDO, with a node splitting and nodal force relaxation algorithm that is capable of generating new crack surfaces to simulate damage initiation and growth in unidirectional fiber reinforced composites. An incremental elastic-plastic algorithm with Jsb2 flow theory and isotropic hardening is incorporated to account for matrix plastic deformation when analyzing damage growth in metal matrix composites. Damage progression in two types of metal matrix composites, namely, the as-received boron/aluminum-5.6/6061-AR and the solution aged and treated boron/aluminum-5.6/6061-T6 metal matrix composites, with thermal residual stresses, have been analyzed. The results show that the thermal residual stresses do have significant effects on the damage initiation, damage progression and the notch strengths of the composite materials.

  19. Explosive Welding of Aluminum, Titanium and Zirconium to Copper Sheet Metal

    NASA Technical Reports Server (NTRS)

    Hegazy, A. A.; Mote, J. D.

    1985-01-01

    The main material properties affecting the explosive weldability of a certain metal combination are the yield strength, the ductility, the density and the sonic velocity of the two metals. Successful welding of the metal combination depends mainly on the correct choice of the explosive welding parameters; i.e., the stand off distance, the weight of the explosive charge relative to the weight of the flyer plate and the detonation velocity of the explosive. Based on the measured and the handbook values of the properties of interest, the explosive welding parameters were calculated and the arrangements for the explosive welding of the Al alloy 6061-T6, titanium and zirconium to OFHC copper were determined. The relatively small sheet metal thickness (1/8") and the fact that the thickness of the explosive layer must exceed a certain minimum value were considered during the determination of the explosive welding conditions. The results of the metallographic investigations and the measurements of the shear strength at the interface demonstrate the usefulness of these calculations to minimize the number of experimental trials.

  20. Aluminum Zintl anion moieties within sodium aluminum clusters

    SciTech Connect

    Wang, Haopeng; Zhang, Xinxing; Ko, Yeon Jae; Grubisic, Andrej; Li, Xiang; Ganteför, Gerd; Bowen, Kit H. E-mail: kiran@mcneese.edu; Schnöckel, Hansgeorg; Eichhorn, Bryan W.; Lee, Mal-Soon; Jena, P.; Kandalam, Anil K. E-mail: kiran@mcneese.edu; Kiran, Boggavarapu E-mail: kiran@mcneese.edu

    2014-02-07

    Through a synergetic combination of anion photoelectron spectroscopy and density functional theory based calculations, we have established that aluminum moieties within selected sodium-aluminum clusters are Zintl anions. Sodium–aluminum cluster anions, Na{sub m}Al{sub n}{sup −}, were generated in a pulsed arc discharge source. After mass selection, their photoelectron spectra were measured by a magnetic bottle, electron energy analyzer. Calculations on a select sub-set of stoichiometries provided geometric structures and full charge analyses for both cluster anions and their neutral cluster counterparts, as well as photodetachment transition energies (stick spectra), and fragment molecular orbital based correlation diagrams.

  1. Aluminum Zintl anion moieties within sodium aluminum clusters

    NASA Astrophysics Data System (ADS)

    Wang, Haopeng; Zhang, Xinxing; Ko, Yeon Jae; Grubisic, Andrej; Li, Xiang; Ganteför, Gerd; Schnöckel, Hansgeorg; Eichhorn, Bryan W.; Lee, Mal-Soon; Jena, P.; Kandalam, Anil K.; Kiran, Boggavarapu; Bowen, Kit H.

    2014-02-01

    Through a synergetic combination of anion photoelectron spectroscopy and density functional theory based calculations, we have established that aluminum moieties within selected sodium-aluminum clusters are Zintl anions. Sodium-aluminum cluster anions, NamAln-, were generated in a pulsed arc discharge source. After mass selection, their photoelectron spectra were measured by a magnetic bottle, electron energy analyzer. Calculations on a select sub-set of stoichiometries provided geometric structures and full charge analyses for both cluster anions and their neutral cluster counterparts, as well as photodetachment transition energies (stick spectra), and fragment molecular orbital based correlation diagrams.

  2. Aluminum Zintl anion moieties within sodium aluminum clusters.

    PubMed

    Wang, Haopeng; Zhang, Xinxing; Ko, Yeon Jae; Grubisic, Andrej; Li, Xiang; Ganteför, Gerd; Schnöckel, Hansgeorg; Eichhorn, Bryan W; Lee, Mal-Soon; Jena, P; Kandalam, Anil K; Kiran, Boggavarapu; Bowen, Kit H

    2014-02-01

    Through a synergetic combination of anion photoelectron spectroscopy and density functional theory based calculations, we have established that aluminum moieties within selected sodium-aluminum clusters are Zintl anions. Sodium-aluminum cluster anions, Na(m)Al(n)(-), were generated in a pulsed arc discharge source. After mass selection, their photoelectron spectra were measured by a magnetic bottle, electron energy analyzer. Calculations on a select sub-set of stoichiometries provided geometric structures and full charge analyses for both cluster anions and their neutral cluster counterparts, as well as photodetachment transition energies (stick spectra), and fragment molecular orbital based correlation diagrams. PMID:24511934

  3. First principles pseudopotential calculations on aluminum and aluminum alloys

    SciTech Connect

    Davenport, J.W.; Chetty, N.; Marr, R.B.; Narasimhan, S.; Pasciak, J.E.; Peierls, R.F.; Weinert, M.

    1993-12-31

    Recent advances in computational techniques have led to the possibility of performing first principles calculations of the energetics of alloy formation on systems involving several hundred atoms. This includes impurity concentrations in the 1% range as well as realistic models of disordered materials (including liquids), vacancies, and grain boundaries. The new techniques involve the use of soft, fully nonlocal pseudopotentials, iterative diagonalization, and parallel computing algorithms. This approach has been pioneered by Car and Parrinello. Here the authors give a review of recent results using parallel and serial algorithms on metallic systems including liquid aluminum and liquid sodium, and also new results on vacancies in aluminum and on aluminum-magnesium alloys.

  4. Aluminum plasmonic photocatalysis

    PubMed Central

    Hao, Qi; Wang, Chenxi; Huang, Hao; Li, Wan; Du, Deyang; Han, Di; Qiu, Teng; Chu, Paul K.

    2015-01-01

    The effectiveness of photocatalytic processes is dictated largely by plasmonic materials with the capability to enhance light absorption as well as the energy conversion efficiency. Herein, we demonstrate how to improve the plasmonic photocatalytic properties of TiO2/Al nano-void arrays by overlapping the localized surface plasmon resonance (LSPR) modes with the TiO2 band gap. The plasmonic TiO2/Al arrays exhibit superior photocatalytic activity boasting an enhancement of 7.2 folds. The underlying mechanisms concerning the radiative energy transfer and interface energy transfer processes are discussed. Both processes occur at the TiO2/Al interface and their contributions to photocatalysis are evaluated. The results are important to the optimization of aluminum plasmonic materials in photocatalytic applications. PMID:26497411

  5. Spray Rolling Aluminum Strip

    SciTech Connect

    Lavernia, E.J.; Delplanque, J-P; McHugh, K.M.

    2006-05-10

    Spray forming is a competitive low-cost alternative to ingot metallurgy for manufacturing ferrous and non-ferrous alloy shapes. It produces materials with a reduced number of processing steps, while maintaining materials properties, with the possibility of near-net-shape manufacturing. However, there are several hurdles to large-scale commercial adoption of spray forming: 1) ensuring strip is consistently flat, 2) eliminating porosity, particularly at the deposit/substrate interface, and 3) improving material yield. Through this program, a new strip/sheet casting process, termed spray rolling, has been developed, which is an innovative manufacturing technique to produce aluminum net-shape products. Spray rolling combines the benefits of twin-roll casting and conventional spray forming, showing a promising potential to overcome the above hurdles associated with spray forming. Spray rolling requires less energy and generates less scrap than conventional processes and, consequently, enables the development of materials with lower environmental impacts in both processing and final products. Spray Rolling was developed as a collaborative project between the University of California-Davis, the Colorado School of Mines, the Idaho National Engineering and Environmental Laboratory, and an industry team. The following objectives of this project were achieved: (1) Demonstration of the feasibility of the spray rolling process at the bench-scale level and evaluation of the materials properties of spray rolled aluminum strip alloys; and (2) Demonstration of 2X scalability of the process and documentation of technical hurdles to further scale up and initiate technology transfer to industry for eventual commercialization of the process.

  6. Aluminum toxicity. Hematological effects.

    PubMed

    Mahieu, S; del Carmen Contini, M; Gonzalez, M; Millen, N; Elias, M M

    2000-01-01

    Sequential effects of intoxication with aluminum hydroxide (Al) (80 mg/Kg body weight, i.p., three times a week), were studied on rats from weaning and up to 28 weeks. The study was carried out on hematological and iron metabolism-related parameters on peripheral blood, at the end of the 1st, 2nd, 3rd, 4th, 5th and 6th months of exposure. As it was described that hematotoxic effects of Al are mainly seen together with high levels of uremia, renal function was measured at the same periods. The animals treated developed a microcytosis and was accompanied by a decrease in mean corpuscular hemoglobin (MCH). Significantly lower red blood cell counts (RBC million/microl) were found in rats treated during the 1st month. These values matched those obtained for control rats during the 2nd month. From the 3rd month onwards, a significant increase was observed as compared to control groups, and the following values were obtained by the 6th month: (T) 10.0 +/- 0.3 versus (C) 8.7 +/- 0.2 (million/microl). Both MCH and mean corpuscular volume (MCV) were found to be significantly lower in groups treated from the 2nd month. At the end of the 6th month the following values were found: MCH (T) 13.3 +/- 0.1 versus (C) 16.9 +/- 0.3 (pg); MCV (T) 42.1 +/- 0.7 versus (C) 51.8 +/- 0.9 (fl). Al was found responsible for lower serum iron concentration levels and in the percentage of transferrin saturation. Thus, although microcytic anemia constitutes an evidence of chronic aluminum exposure, prolonged exposure could lead to a recovery of hematocrit and hemoglobin concentration values with an increase in red cell number. Nevertheless, both microcytosis and the decrease of MCH would persist. These modifications took place without changes being observed in the renal function during the observation period. PMID:10643868

  7. Analytical model to evaluate interface characteristics of carbon nanotube reinforced aluminum oxide nanocomposites

    NASA Astrophysics Data System (ADS)

    Chen, Yao; Balani, Kantesh; Agarwal, Arvind

    2008-01-01

    This research presents an analytical method to investigate the effect of volume fraction and the number of outer walls of multiwalled carbon nanotube (MWNT) reinforcement on load carrying capability in the aluminum oxide matrix. Interfacial shear stress transfer and energy dissipation have been estimated using the Cox model. Critical energy release rate for the debonding of MWNT from the matrix is also estimated based on the crack deflection. The computed results sufficiently manifest that MWNT pullout and crack deflection contributes greatly to improved fracture toughness of carbon nanotube reinforced aluminum oxide nanocomposites.

  8. Aluminum: Industry of the future

    SciTech Connect

    1998-11-01

    For over a century, the US aluminum industry has led the global market with advances in technology, product development, and marketing. Industry leaders recognize both the opportunities and challenges they face as they head into the 21st century, and that cooperative R and D is key to their success. In a unique partnership, aluminum industry leaders have teamed with the US Department of Energy`s Office of Industrial Technologies (OIT) to focus on innovative technologies that will help to strengthen the competitive position of the US aluminum industry and, at the same time, further important national goals. This industry-led partnership, the Aluminum Industry of the Future, promotes technologies that optimize the use of energy and materials in operations and reduce wastes and energy-related emissions. Led by The Aluminum Association, industry leaders began by developing a unified vision of future market, business, energy, and environmental goals. Their vision document, Partnerships for the Future, articulates a compelling vision for the next 20 years: to maintain and grow the aluminum industry through the manufacture and sale of competitively priced, socially desirable, and ecologically sustainable products. Continued global leadership in materials markets will require the combined resources of industry, universities, and government laboratories. By developing a unified vision, the aluminum industry has provided a framework for the next step in the Industries of the Future process, the development of a technology roadmap designed to facilitate cooperative R and D.

  9. Thermal contact conductance between metals in a vacuum environment

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Basic heat transfer data for structural materials used in the Saturn 1B/V 1U component case structural design were obtained. The main emphasis is on thermal contact conductance between dissimilar metallic surfaces, since thermal conductivity values within solids have been sufficiently established previously. The test program outline and test results are described. The following materials were tested: aluminum 6061-T6 (12 samples), aluminum 356 (as cast), almag 35 (as cast), magnesium AZ91C-T4 (4 samples), and mag lithium LA-141 (2 samples).

  10. Hypervelocity impact testing of non-metallic materials

    NASA Technical Reports Server (NTRS)

    Schonberg, William P.

    1990-01-01

    A comparative analysis of impact damage in composite and ceramic specimens and in geometrically similar aluminum specimens is performed to determine the advantages and disadvantages of employing certain composite and ceramic materials in the design of structural wall systems for long-duration spacecraft. A similar analysis of the damage in single panel lexan and multi-plane glass windows shows that glass window systems are rather resilent under hypervelocity impact loadings. It is concluded that thin Kevlar 49, IM6/3501-6 graphite/epoxy, and alumina panels offer no advantage over equivalent aluminum 6061-T6 panels in reducing the penetration threat of hypervelocity projectiles.

  11. Surface characterization of selected LDEF tray clamps

    NASA Technical Reports Server (NTRS)

    Cromer, T. F.; Grammer, H. L.; Wightman, J. P.; Young, Philip R.; Slemp, Wayne S.

    1993-01-01

    The surface characterization of chromic acid anodized 6061-T6 aluminum alloy tray clamps has shown differences in surface chemistry depending upon the position on the Long Duration Exposure Facility (LDEF). Water contact angle results showed no changes in wettability of the tray clamps. The overall surface topography of the control, trailing edge(E3) and leading edge(D9) samples was similar. The thickness of the aluminum oxide layer for all samples determined by Auger depth profiling was less than one micron. X-ray photoelectron spectroscopy (XPS) analysis of the tray clamps showed significant differences in the surface composition. Carbon and silicon containing compounds were the primary contaminants detected.

  12. Subsurface Aluminum Nitride Formation in Iron-Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Bott, June H.

    Transformation-induced plasticity (TRIP) steels containing higher amounts of aluminum than conventional steels are ideal for structural automotive parts due to their mechanical properties. However, the aluminum tends to react with any processing environment at high temperatures and therefore presents significant challenges during manufacturing. One such challenge occurs during secondary cooling, reheating, and hot-rolling and is caused by a reaction with nitrogen-rich atmospheres wherein subsurface aluminum nitride forms in addition to internal and external oxides. The nitrides are detrimental to mechanical properties and cause surface cracks. It is important to understand how these nitrides and oxides form and their consequences for the quality of steel products. This study looks at model iron-aluminum (up to 8 wt.% aluminum) alloys and uses confocal laser scanning microscopy, x-ray diffraction, scanning electron microscopy with energy dispersive x-ray spectrometry, and transmission electron microscopy to study the effect of various conditions on the growth and development of these precipitates in a subsurface oxygen-depleted region. By using model alloys and controlling the experimental atmosphere, this study is able to understand some of the more fundamental materials science behind aluminum nitride formation in aluminum-rich iron alloys and the relationship between internal nitride and oxide precipitation and external oxide scale morphology and composition. The iron-aluminum alloys were heated in N2 atmospheres containing oxygen impurities. It was found that nitrides formed when bulk aluminum content was below 8 wt.% when oxygen was sufficiently depleted due to the internal oxidation. In the samples containing 1 wt.% aluminum, the depth of the internal oxide and nitride zones were in agreement with a diffusion-based model. Increasing aluminum content to 3 and 5 wt% had the effects of modifying the surface-oxide scale composition and increasing its continuity

  13. [Microbiological corrosion of aluminum alloys].

    PubMed

    Smirnov, V F; Belov, D V; Sokolova, T N; Kuzina, O V; Kartashov, V R

    2008-01-01

    Biological corrosion of ADO quality aluminum and aluminum-based construction materials (alloys V65, D16, and D16T) was studied. Thirteen microscopic fungus species and six bacterial species proved to be able to attack aluminum and its alloys. It was found that biocorrosion of metals by microscopic fungi and bacteria was mediated by certain exometabolites. Experiments on biocorrosion of the materials by the microscopic fungus Alternaria alternata, the most active biodegrader, demonstrated that the micromycete attack started with the appearance of exudate with pH 8-9 on end faces of the samples. PMID:18669265

  14. Plasma Source Ion Implantation of Aluminum and Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Walter, Kevin Carl

    Three plasma source ion implantation (PSII) schemes applied to three aluminum systems have been studied. Pure aluminum, and aluminum alloys 7075 (Al-Cu-Mg-Zn) and A390 (Al-17Si-Cu-Fe) were (1) argon ion sputter-cleaned and nitrogen-implanted, (2) nitrogen-implanted without sputter -cleaning, and (3) argon-implanted. Nitrogen implantation was performed with the goal of modifying the surface properties by transformation of the surface to aluminum-nitride. Argon implantation was performed with the goal of modifying the surface properties by inducing radiation damage. All implantation schemes were accomplished using a glow discharge mode of the PSII process. Implanted surfaces were investigated using Auger depth profiling and Transmission Electron Microscopy. The profiles indicated a stoichiometric layer, ~ 0.15 μm thick, of AlN on the nitrogen-implanted samples. Electron microscopy confirmed the complete conversion of the aluminum surface to AlN. Knoop microhardness tests showed an increase in surface hardness, especially at low loads. The improvements were independent of prior sputter-cleaning and were approximately equal for the studied aluminum systems. Pin-on-disk wear tests were conducted using a ruby stylus and isopropanol lubrication. Argon implantation decreased the wear resistance of pure aluminum and 7075. Nitrogen implantation improved the wear rates by a factor of ~10 for pure aluminum and 7075. These improvements were independent of prior sputter-cleaning. The coefficient of friction was not significantly influenced by the implantation schemes. Due to a coarse microstructure, tribological tests of ion-implanted A390 were inconclusive. Corrosion studies performed in a 3.5 wt% NaCl solution (seawater) indicated nitrogen implantation gave pure aluminum improved corrosion resistance. The improvement is due to the complete conversion of the aluminum surface to AlN. Because of pre-existing precipitates, the corrosion properties of 7075 and A390 were not

  15. PREPARATION OF URANIUM-ALUMINUM ALLOYS

    DOEpatents

    Moore, R.H.

    1962-09-01

    A process is given for preparing uranium--aluminum alloys from a solution of uranium halide in an about equimolar molten alkali metal halide-- aluminum halide mixture and excess aluminum. The uranium halide is reduced and the uranium is alloyed with the excess aluminum. The alloy and salt are separated from each other. (AEC)

  16. Fracture criteria for discontinuously reinforced metal matrix composites

    NASA Technical Reports Server (NTRS)

    Rack, H. J.; Goree, J. G.; Albritton, J.; Ratnarparkhi, P.

    1988-01-01

    The effect of sample configuration on the details of initial crack propagation in discontinuously whisker reinforced aluminum metal matrix composites was investigated. Care was taken to allow direct comparison of fracture toughness values utilizing differing sample configurations and orientations, holding all materials variables constant, e.g., extrusion ration, heat treatment, and chemistry.

  17. Fatigue behavior of continuous fiber silicon-carbide-aluminum composites

    NASA Technical Reports Server (NTRS)

    Johnson, W. S.; Wallis, R. R.

    1984-01-01

    Four lay-ups of continuous fiber silicon carbide (SCS2) fiber/aluminum matrix composites were tested to assess fatigue mechanisms including stiffness loss when cycled below their respective fatigue limits. The lay-ups were 0 (sub 8), 0(sub 2)/ + or - 45 (sub 2s), 0/90 (sub 2s),and 0/ + or 45/90 (subs). The data were compared with predictions from the author's previously published shakedown model which predicts fatigue-induced stiffness loss in metal matrix composites. A fifth lay-up, + or - 45 (sub 2s), was tested to compare shakedown and fatigue limits. The particular batch of silicon-carbide fibers tested in this program had a somewhat lower modulus (340 GPa) than expected and displayed poor bonding to the aluminum matrix. Good agreement was obtained between the stiffness loss model and the test data. The fatigue damage below the fatigue limit was primarily in the form of matrix cracking. The fatigue limit corresponded to the laminate shakedown for the + or - 45 (sub 2s) laminate.

  18. Electrolyte treatment for aluminum reduction

    DOEpatents

    Brown, Craig W.; Brooks, Richard J.; Frizzle, Patrick B.; Juric, Drago D.

    2002-01-01

    A method of treating an electrolyte for use in the electrolytic reduction of alumina to aluminum employing an anode and a cathode, the alumina dissolved in the electrolyte, the treating improving wetting of the cathode with molten aluminum during electrolysis. The method comprises the steps of providing a molten electrolyte comprised of ALF.sub.3 and at least one salt selected from the group consisting of NaF, KF and LiF, and treating the electrolyte by providing therein 0.004 to 0.2 wt. % of a transition metal or transition metal compound for improved wettability of the cathode with molten aluminum during subsequent electrolysis to reduce alumina to aluminum.

  19. Chrome - Free Aluminum Coating System

    NASA Technical Reports Server (NTRS)

    Bailey, John H.; Gugel, Jeffrey D.

    2010-01-01

    This slide presentation concerns the program to qualify a chrome free coating for aluminum. The program was required due to findings by OSHA and EPA, that hexavalent chromium, used to mitigate corrosion in aerospace aluminum alloys, poses hazards for personnel. This qualification consisted of over 4,000 tests. The tests revealed that a move away from Cr+6, required a system rather than individual components and that the maximum corrosion protection required pretreatment, primer and topcoat.

  20. Aluminum laser welding optimization

    NASA Astrophysics Data System (ADS)

    Chmelíčková, Hana; Halenka, Viktor; Lapšanská, Hana; Havelková, Martina

    2007-04-01

    Pulsed Nd:YAG laser with maximal power 150 W is used in our laboratory to cut, drill and weld metal and non-metal thin materials to thickness 2 mm. Welding is realized by fixed processing head or movable fiber one with beam diameter 0,6 mm in focus plane. Welding of stainless and low-carbon steel was tested before and results are publicized and used in practice. Now the goal of our experiment was optimization of process parameters for aluminum that has other physical properties than steels, lower density, higher heat conductivity and surface reflexivity. Pure alumina specimen 0,8 mm and Al-Mg-Si alloy 0,5 mm prepared for butt welds. Problem with surface layer of Al IIO 3 was overcome by sanding and chemical cleaning with grinding paste. Critical parameters for good weld shape are specimen position from beam focus plane, pulse length and energy, pulse frequency and the motion velocity that determines percentage of pulse overlap. Argon as protective gas was used with speed 6 liters per second. Thermal distribution in material can be modeled by numerical simulation. Software tool SYSWELD makes possible to fit laser as surface heat source, define weld geometry, and make meshing of specimen to finite elements and compute heat conduction during process. Color isotherms, vectors, mechanical deformations and others results can be study in post-processing.

  1. Anodized aluminum on LDEF

    NASA Technical Reports Server (NTRS)

    Golden, Johnny L.

    1993-01-01

    A compilation of reported analyses and results obtained for anodized aluminum flown on the Long Duration Exposure Facility (LDEF) was prepared. Chromic acid, sulfuric acid, and dyed sulfuric acid anodized surfaces were exposed to the space environment. The vast majority of the anodized surface on LDEF was chromic acid anodize because of its selection as a thermal control coating for use on the spacecraft primary structure, trays, tray clamps, and space end thermal covers. Reports indicate that the chromic acid anodize was stable in solar absorptance and thermal emittance, but that contamination effects caused increases in absorptance on surfaces exposed to low atomic oxygen fluences. There were some discrepancies, however, in that some chromic acid anodized specimens exhibited significant increases in absorptance. Sulfuric acid anodized surfaces also appeared stable, although very little surface area was available for evaluation. One type of dyed sulfuric acid anodize was assessed as an optical baffle coating and was observed to have improved infrared absorptance characteristics with exposure on LDEF.

  2. Managing aluminum phosphide poisonings

    PubMed Central

    Gurjar, Mohan; Baronia, Arvind K; Azim, Afzal; Sharma, Kalpana

    2011-01-01

    Aluminum phosphide (AlP) is a cheap, effective and commonly used pesticide. However, unfortunately, it is now one of the most common causes of poisoning among agricultural pesticides. It liberates lethal phosphine gas when it comes in contact either with atmospheric moisture or with hydrochloric acid in the stomach. The mechanism of toxicity includes cellular hypoxia due to the effect on mitochondria, inhibition of cytochrome C oxidase and formation of highly reactive hydroxyl radicals. The signs and symptoms are nonspecific and instantaneous. The toxicity of AlP particularly affects the cardiac and vascular tissues, which manifest as profound and refractory hypotension, congestive heart failure and electrocardiographic abnormalities. The diagnosis of AlP usually depends on clinical suspicion or history, but can be made easily by the simple silver nitrate test on gastric content or on breath. Due to no known specific antidote, management remains primarily supportive care. Early arrival, resuscitation, diagnosis, decrease the exposure of poison (by gastric lavage with KMnO4, coconut oil), intensive monitoring and supportive therapy may result in good outcome. Prompt and adequate cardiovascular support is important and core in the management to attain adequate tissue perfusion, oxygenation and physiologic metabolic milieu compatible with life until the tissue poison levels are reduced and spontaneous circulation is restored. In most of the studies, poor prognostic factors were presence of acidosis and shock. The overall outcome improved in the last decade due to better and advanced intensive care management. PMID:21887030

  3. Managing aluminum phosphide poisonings.

    PubMed

    Gurjar, Mohan; Baronia, Arvind K; Azim, Afzal; Sharma, Kalpana

    2011-07-01

    Aluminum phosphide (AlP) is a cheap, effective and commonly used pesticide. However, unfortunately, it is now one of the most common causes of poisoning among agricultural pesticides. It liberates lethal phosphine gas when it comes in contact either with atmospheric moisture or with hydrochloric acid in the stomach. The mechanism of toxicity includes cellular hypoxia due to the effect on mitochondria, inhibition of cytochrome C oxidase and formation of highly reactive hydroxyl radicals. The signs and symptoms are nonspecific and instantaneous. The toxicity of AlP particularly affects the cardiac and vascular tissues, which manifest as profound and refractory hypotension, congestive heart failure and electrocardiographic abnormalities. The diagnosis of AlP usually depends on clinical suspicion or history, but can be made easily by the simple silver nitrate test on gastric content or on breath. Due to no known specific antidote, management remains primarily supportive care. Early arrival, resuscitation, diagnosis, decrease the exposure of poison (by gastric lavage with KMnO(4), coconut oil), intensive monitoring and supportive therapy may result in good outcome. Prompt and adequate cardiovascular support is important and core in the management to attain adequate tissue perfusion, oxygenation and physiologic metabolic milieu compatible with life until the tissue poison levels are reduced and spontaneous circulation is restored. In most of the studies, poor prognostic factors were presence of acidosis and shock. The overall outcome improved in the last decade due to better and advanced intensive care management. PMID:21887030

  4. Carbide coated fibers in graphite-aluminum composites

    NASA Technical Reports Server (NTRS)

    Imprescia, R. J.; Levinson, L. S.; Reiswig, R. D.; Wallace, T. C.; Williams, J. M.

    1975-01-01

    The NASA-supported program at the Los Alamos Scientific Laboratory (LASL) to develop carbon fiber-aluminum matrix composites is described. Chemical vapor deposition (CVD) was used to uniformly deposit thin, smooth, continuous coats of TiC on the fibers of graphite tows. Wet chemical coating of fibers, followed by high-temperature treatment, was also used, but showed little promise as an alternative coating method. Strength measurements on CVD coated fiber tows showed that thin carbide coats can add to fiber strength. The ability of aluminum alloys to wet TiC was successfully demonstrated using TiC-coated graphite surfaces. Pressure-infiltration of TiC- and ZrC-coated fiber tows with aluminum alloys was only partially successful. Experiments were performed to evaluate the effectiveness of carbide coats on carbon as barriers to prevent reaction between alluminum alloys and carbon. Initial results indicate that composites of aluminum and carbide-coated graphite are stable for long periods of time at temperatures near the alloy solidus.

  5. Improved measurement of aluminum in irradiated fuel reprocessed at the Savannah River Site

    SciTech Connect

    Maxwell, S.L. III

    1991-12-31

    At the Savannah River Site (SRS), irradiated fuel from research reactor operators or their contract fuel service companies is reprocessed in the H-Canyon Separations Facility. Final processing costs are based on analytical measurements of the amount of total metal dissolved. Shipper estimates for uranium and uranium-235 and measured values at SRS have historically agreed very well. There have occasionally been significant differences between shipper estimates for aluminum and the aluminum content determined at SRS. To minimize analytical error that might contribute to poor shipper-receiver agreement for the reprocessing of off-site fuel, a new analytical method to measure aluminum was developed by SRS Analytical Laboratories at the Central Laboratory Facilities. An EDTA (ethylenediaminetetraacetic acid) titration method, subject to dissolver matrix interferences, was previously used at SRS to measure aluminum in H-Canyon dissolver during the reprocessing of offsite fuel. The new method combines rapid ion exchange technology with direct current argon plasma spectrometry to enhance the reliability of aluminum measurements for off-site fuel. The technique rapidly removes spectral interferences such as uranium and significantly lowers gamma levels due to fission products. Aluminium is separated quantitatively by using an anion exchange technique that employs oxalate complexing, small particle size resin and rapid flow rates. The new method, which has eliminated matrix interference problems with these analyses and improved the quality of aluminum measurements, has improved the overall agreement between shipper-receiver values for offsite fuel processed SRS.

  6. Improved measurement of aluminum in irradiated fuel reprocessed at the Savannah River Site

    SciTech Connect

    Maxwell, S.L. III.

    1991-01-01

    At the Savannah River Site (SRS), irradiated fuel from research reactor operators or their contract fuel service companies is reprocessed in the H-Canyon Separations Facility. Final processing costs are based on analytical measurements of the amount of total metal dissolved. Shipper estimates for uranium and uranium-235 and measured values at SRS have historically agreed very well. There have occasionally been significant differences between shipper estimates for aluminum and the aluminum content determined at SRS. To minimize analytical error that might contribute to poor shipper-receiver agreement for the reprocessing of off-site fuel, a new analytical method to measure aluminum was developed by SRS Analytical Laboratories at the Central Laboratory Facilities. An EDTA (ethylenediaminetetraacetic acid) titration method, subject to dissolver matrix interferences, was previously used at SRS to measure aluminum in H-Canyon dissolver during the reprocessing of offsite fuel. The new method combines rapid ion exchange technology with direct current argon plasma spectrometry to enhance the reliability of aluminum measurements for off-site fuel. The technique rapidly removes spectral interferences such as uranium and significantly lowers gamma levels due to fission products. Aluminium is separated quantitatively by using an anion exchange technique that employs oxalate complexing, small particle size resin and rapid flow rates. The new method, which has eliminated matrix interference problems with these analyses and improved the quality of aluminum measurements, has improved the overall agreement between shipper-receiver values for offsite fuel processed SRS.

  7. Ceramic fiber-reinforced monoclinic celsian phase glass-ceramic matrix composite material

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P. (Inventor); Dicarlo, James A. (Inventor)

    1994-01-01

    A hyridopolysilazane-derived ceramic fiber reinforced monoclinic celsian phase barium aluminum silicate glass-ceramic matrix composite material is prepared by ball-milling an aqueous slurry of BAS glass powder and fine monoclinic celsian seeds. The fibers improve the mechanical strength and fracture toughness and with the matrix provide superior dielectric properties.

  8. In-situ processing of aluminum nitride particle reinforced aluminum alloy composites

    NASA Astrophysics Data System (ADS)

    Zheng, Qingjun

    Discontinuously reinforced aluminum alloy composites (DRACs) have potential applications in automotive, electronic packaging, and recreation industries. Conventional processing of DRACs is by incorporation of ceramic particles/whiskers/fibers into matrix alloys. Because of the high cost of ceramic particles, DRACs are expensive. The goal of this work was to develop a low-cost route of AlN-Al DRACs processing through bubbling and reacting nitrogen and ammonia gases with aluminum alloy melt in the temperature range of 1373--1523 K. Thermodynamic analysis of AlN-Al alloy system was performed based on Gibbs energy minimization theory. AlN is stable in aluminum, Al-Mg, Al-Si, Al-Zn, and Al-Li alloys over the whole temperature range for application and processing of DRACs. Experiments were carried out to form AlN by bubbling nitrogen and ammonia gases through aluminum, Al-Mg, and Al-Si alloy melts. Products were characterized with XRD, SEM, and EDX. The results showed that in-situ processing of AlN reinforced DRACs is technically feasible. Significant AlN was synthesized by bubbling deoxidized nitrogen and ammonia gases. When nitrogen gas was used as the nitrogen precursor, the AlN particles formed in-situ are small in size, (<10 mum). The formation of AlN is strongly affected by the trace oxygen impurities in the nitrogen gas. The deleterious effect of oxygen impurities is due to their inhibition to the chemisorption of nitrogen gas at the interface. In comparison with nitrogen gas, bubbling ammonia led to formation of AlN particles in smaller size (about 2 mum or less) at a significantly higher rate. Ammonia is not stable and dissociated into nitrogen and hydrogen at reaction temperatures. The hydrogen functions as oxygen-getter at the interface and benefits chemisorption of nitrogen, thereby promoting the formation of AlN. The overall process of AlN formation was modeled using two-film model. For nitrogen bubbling gas, the whole process is controlled by chemisorption

  9. Infiltration kinetics of aluminum in silicon carbide compacts. Annual report

    SciTech Connect

    Edwards, G.R.; Olson, D.L.

    1987-07-01

    Although metal-matrix composites have been fabricated by various techniques, the most successful are solid state processes such as powder metallurgy and diffusion bonding. Liquid-metal processes such as compucasting, pultrusion, and infiltration, while less successful, are potentially more economical. The advantages of producing silicon carbide-aluminum matrix composites by liquid-metal infiltration techniques can not be fully realized without an improved understanding of the infiltration behavior and the fiber/matrix bonding mechanisms. This paper reports on infiltration models which consider the physical properties of the liquid and preform (either porous compact or capillary/tube bundle). These properties include viscosity, density, surface tension, and wettability (pore shape and size in the case of the porous compact). The models have been assessed in terms of their ability to predict infiltration behavior from known physical properties of the materials.

  10. Electrocomposite of Alumina in Nickel Matrix

    NASA Technical Reports Server (NTRS)

    Xiong-Skiba, Pei; Hulguin, Ryan; Engelhaupt, Darell; Ramsey, Brian

    2004-01-01

    Nickel/aluminum oxide composite was electroformed in a sulfamate bath with 50 g/L of 0.05-micron aluminum oxide powder. Different plating methods including direct current plating, periodic pulse plating, and periodic reverse pulse plating were used. With conventional direct current plating, the maximum particle inclusion in the nickel matrix remains about 2% (wt). However, much higher percentile particle inclusions were achieved when a specific pulse reversal plating technique was applied. The particle incorporation approaches theoretical maximum when the deposit thickness per cycle approaches the particle diameter size at lower duty cycle. The highest particle incorporation achieved is 23% (by weight). Conceptual models interpreting the dramatic differences in the results of these plating methods were also proposed.

  11. The Diametrically Loaded Cylinder For The Study Of Nanostructured Aluminum-Graphene And Aluminum-Alumina Nanocomposites Using Digital Image Correlation

    NASA Astrophysics Data System (ADS)

    Tabandeh Khorshid, Meysam; Schultz, Benjamin; Rohatgi, Pradeep; Elhajjar, Rani

    2016-05-01

    Non-contact methods for characterization of metal matrix composites have the potential to accelerate the development and study of advanced composite materials. In this study, diametrical compression of small disk specimens was used to understand the mechanical properties of metal matrix micro and nano composites. Analysis was performed using an inverse method that couples digital image correlation and the analytical closed form formulation. This technique was capable of extracting the tension and compression modulus values in the metal matrix nanocomposite disk specimens. Specimens of aluminum and aluminum reinforced with either Al2O3 nanoparticles or graphene nanoplatelets (GNP) were synthesized using a powder metallurgy approach that involved room temperature milling in ethanol, and low temperature drying followed by single action compaction. The elastic and failure properties of MMNC materials prepared using the procedure above are presented.

  12. Low-aluminum content iron-aluminum alloys

    SciTech Connect

    Sikka, V.K.; Goodwin, G.M.; Alexander, D.J.

    1995-06-01

    The low-aluminum-content iron-aluminum program deals with the development of a Fe-Al alloy with aluminum content such as a produce the minimum environmental effect at room temperature. The FAPY is an Fe-16 at. % Al-based alloy developed at the Oak Ridge National Laboratory as the highest aluminum-containing alloy with essentially no environmental effect. The chemical composition for FAPY in weight percent is: aluminum = 8.46, chromium = 5.50, zirconium = 0.20, carbon = 0.03, molybdenum = 2.00, yttrium = 0.10 and iron = 83.71. The ignots of the alloy can be hot worked by extrusion, forging, and rolling processes. The hot-worked cast structure can be cold worked with intermediate anneals at 800{degrees}C. Typical room-temperature ductility of the fine-grained wrought structure is 20 to 25% for this alloy. In contrast to the wrought structure, the cast ductility at room temperature is approximately 1% with a transition temperature of approximately 100 to 150{degrees}C, above which ductility values exceed 20%. The alloy has been melted and processed into bar, sheet, and foil. The alloy has also been cast into slabs, step-blocks of varying thicknesses, and shapes. The purpose of this section is to describe the welding response of cast slabs of three different thicknesses of FAPY alloy. Tensile, creep, and Charpy-impact data of the welded plates are also presented.

  13. Commonwealth Aluminum: Manufacturer Conducts Plant-Wide Energy Assessments at Two Aluminum Sheet Production Operations;

    SciTech Connect

    Not Available

    2006-04-01

    DOE Industrial Technologies Program case study describes the savings possible if Commonwealth Aluminum (now Aleris Rolled Products) makes improvements noted in energy assessments at two aluminum mills.

  14. Commonwealth Aluminum: Manufacturer Conducts Plant-Wide Energy Assessments at Two Aluminum Sheet Production Operations

    SciTech Connect

    2006-04-01

    DOE Industrial Technologies Program case study describes the savings possible if Commonwealth Aluminum (now Aleris Rolled Products) makes improvements noted in energy assessments at two aluminum mills.

  15. Effective Thermal Conductivity of an Aluminum Foam + Water Two Phase System

    NASA Technical Reports Server (NTRS)

    Moskito, John

    1996-01-01

    This study examined the effect of volume fraction and pore size on the effective thermal conductivity of an aluminum foam and water system. Nine specimens of aluminum foam representing a matrix of three volume fractions (4-8% by vol.) and three pore sizes (2-4 mm) were tested with water to determine relationships to the effective thermal conductivity. It was determined that increases in volume fraction of the aluminum phase were correlated to increases in the effective thermal conductivity. It was not statistically possible to prove that changes in pore size of the aluminum foam correlated to changes in the effective thermal conductivity. However, interaction effects between the volume fraction and pore size of the foam were statistically significant. Ten theoretical models were selected from the published literature to compare against the experimental data. Models by Asaad, Hadley, and de Vries provided effective thermal conductivity predictions within a 95% confidence interval.

  16. Comparison Of Models Of Metal-Matrix Composites

    NASA Technical Reports Server (NTRS)

    Bigelow, C. A.; Johnson, W. S.; Naik, R. A.

    1994-01-01

    Report presents comparative review of four mathematical models of micromechanical behaviors of fiber/metal-matrix composite materials. Models differ in various details, all based on properties of fiber and matrix constituent materials, all involve square arrays of fibers continuous and parallel and all assume complete bonding between constituents. Computer programs implementing models used to predict properties and stress-vs.-strain behaviors of unidirectional- and cross-ply laminated composites made of boron fibers in aluminum matrices and silicon carbide fibers in titanium matrices. Stresses in fiber and matrix constituent materials also predicted.

  17. Hybrid matrix fiber composites

    DOEpatents

    Deteresa, Steven J.; Lyon, Richard E.; Groves, Scott E.

    2003-07-15

    Hybrid matrix fiber composites having enhanced compressive performance as well as enhanced stiffness, toughness and durability suitable for compression-critical applications. The methods for producing the fiber composites using matrix hybridization. The hybrid matrix fiber composites include two chemically or physically bonded matrix materials, whereas the first matrix materials are used to impregnate multi-filament fibers formed into ribbons and the second matrix material is placed around and between the fiber ribbons that are impregnated with the first matrix material and both matrix materials are cured and solidified.

  18. Interferometric phase measurement of zerodur, aluminum and SXA mirrors at cryogenic temperatures

    NASA Technical Reports Server (NTRS)

    Magner, Thomas J.; Barney, Richard D.

    1988-01-01

    A research program was undertaken to determine the surface figure error of several different types of mirrors at cryogenic temperatures. Two-inch diameter parabolic, spherical and flat mirrors were fabricated from zerodur, aluminum and a metal matrix composite of silicon carbide reinforced aluminum (SXA). The ratio of silicon carbide to aluminum was selected so that the coefficient of thermal expansion (CTE) of the metal matrix matched electroless nickel. A liquuid helium dewar was modified to add an interferometric grade window, a cold electronic shutter and a strain-free copper mirror mount. Interferometric phase measurements on each mirror mounted in the dewar were made without the window, with the window, under vacuum, at around 80K and between 10K and 24K.

  19. Improved Irradiation Performance of Uranium-Molybdenum/Aluminum Dispersion Fuel by Silicon Addition in Aluminum

    SciTech Connect

    Yeon Soo Kim; G. L. Hofman; A. B. Robinson; D. M. Wachs

    2013-10-01

    Uranium-molybdenum fuel particle dispersion in aluminum is a form of fuel under development for conversion of high-power research and test reactors from highly enriched to low-enriched uranium in the U.S. Global Threat Reduction Initiative program (also known as the Reduced Enrichment for Research and Test Reactors program). Extensive irradiation tests have been conducted to find a solution for problems caused by interaction layer growth and pore formation between U-Mo and Al. Adding a small amount of Si (up to [approximately]5 wt%) in the Al matrix was one of the proposed remedies. The effect of silicon addition in the Al matrix was examined using irradiation test results by comparing side-by-side samples with different Si additions. Interaction layer growth was progressively reduced with increasing Si addition to the matrix Al, up to 4.8 wt%. The Si addition also appeared to delay pore formation and growth between the U-Mo and Al.

  20. First principles pseudopotential calculations on aluminum and aluminum alloys

    SciTech Connect

    Davenport, J.W.; Chetty, N.; Marr, R.B.; Narasimhan, S.; Pasciak, J.E.; Peierls, R.F.; Weinert, M.; Rahman, T.S.

    1994-12-31

    Recent advances in computational techniques have led to the possibility of performing first principles calculations of the energetics of alloy formation on systems involving several hundred atoms. This includes impurity concentrations in the 1% range as well as realistic models of disordered materials (including liquids), vacancies, and grain boundaries. The new techniques involve the use of soft, fully nonlocal pseudopotentials, iterative diagonalization, and parallel computing algorithms. This approach has been pioneered by Car and Parrinello. Here the authors give a review of recent results using parallel and serial algorithms by their group on metallic systems including liquid aluminum and liquid sodium, and also new results on vacancies in aluminum and on aluminum-magnesium alloys.

  1. Solutionizing effects during corrosive wear in 6061 aluminum and composites

    SciTech Connect

    Varma, S.K.; Andrews, S.

    1998-02-01

    Samples of commercial 6061 aluminum alloy in both the monolithic form and reinforced with 0.1 and 0.2 volume fraction of alumina particles were solutionized for 5, 10, and 20 h at 540 C. A transient current generated in the composite material as a result of continuous and impact scratching during the corrosive wear process shows that composites are more sensitive to the microstructural changes taking place during solutionizing than is the monolithic 6061 alloy. The increase in grain size in the alloy during solutionizing does not significantly affect the transient current. Decohesion of the particles in the composites increases the interfacial area, and this interfacial region may act as an anodic site for corrosion to occur. Dislocations generated due to differences in the coefficient of thermal expansion values for alumina particles and aluminum matrix increase the measured transient current.

  2. Capillarity in isothermal infiltration of alumina fiber preforms with aluminum

    SciTech Connect

    Michaud, V.J.; Mortensen, A. . Dept. of Materials Science); Compton, L.M. )

    1994-10-01

    Models derived in petroleum engineering and soil science for flow of two immiscible fluids in a porous medium are extended to the infiltration of ceramic preforms by a liquid metal. SAFFIL alumina fiber preforms are infiltrated with an aluminum matrix in a series of interrupted unidirectional and isothermal experiments at various low applied pressures, to measure profiles of the volume fraction of metal along the length of the preforms. Comparison of experimental data with theory reveals the existence of a pressure-dependent incubation time for wetting of the alumina preforms by molten aluminum at 973 K. If this incubation time is taken into account, experimental curves of metal distribution are well predicted by theory, confirming the validity of the models after initiation of flow.

  3. Weld Repair of Thin Aluminum Sheet

    NASA Technical Reports Server (NTRS)

    Beuyukian, C. S.; Mitchell, M. J.

    1986-01-01

    Weld repairing of thin aluminum sheets now possible, using niobium shield and copper heat sinks. Refractory niobium shield protects aluminum adjacent to hole, while copper heat sinks help conduct heat away from repair site. Technique limits tungsten/inert-gas (TIG) welding bombardment zone to melt area, leaving surrounding areas around weld unaffected. Used successfully to repair aluminum cold plates on Space Shuttle, Commercial applications, especially in sealing fractures, dents, and holes in thin aluminum face sheets or clad brazing sheet in cold plates, heat exchangers, coolers, and Solar panels. While particularly suited to thin aluminum sheet, this process also used in thicker aluminum material to prevent surface damage near weld area.

  4. Investigation of Thermal Expansion and Physical Properties of Carbon Nanotube Reinforced Nanocrystalline Aluminum Nanocomposite

    NASA Astrophysics Data System (ADS)

    Sharma, Manjula; Sharma, Vimal

    2016-02-01

    Carbon nanotube (CNT) reinforced nanocrystalline aluminum matrix composites are fabricated by a simple and effective physical mixing method with sonication. In this study, the microstructural characterisations and property evaluations of the nanocomposites were performed. The structural characterisations revealed that CNTs were dispersed, embedded, and anchored within the metal matrix. A strong interfacial adhesion appeared between CNTs and nanocrystalline aluminum as a result of the fabrication process. Raman and Fourier transform infrared spectroscopic studies also confirmed the surface adherence of CNTs with nanocrystalline aluminum matrix during the fabrication process. Thermal expansion behaviour of CNT-reinforced aluminum matrix composites was investigated up to 240°C using a dilatometer. The coefficient of thermal expansion of the nanocomposites decreased continuously with the increasing content of CNTs. The maximum reduction of 82% was found for 4 wt% CNTs in the nanocomposite. The coefficient of thermal expansion variation with CNTs was also compared with the predictions from the thermoelastic models. The expansion behaviour of the nanocomposites was correlated to the microstructure, internal stresses, and phase segregations. The electrical and thermal conductivity was also studied and was observed to decrease for all reinforced CNT weight fractions.

  5. Scaleable Clean Aluminum Melting Systems

    SciTech Connect

    Han, Q.; Das, S.K.

    2008-02-15

    The project entitled 'Scaleable Clean Aluminum Melting Systems' was a Cooperative Research and Development Agreements (CRADAs) between Oak Ridge National Laboratory (ORNL) and Secat Inc. The three-year project was initially funded for the first year and was then canceled due to funding cuts at the DOE headquarters. The limited funds allowed the research team to visit industrial sites and investigate the status of using immersion heaters for aluminum melting applications. Primary concepts were proposed on the design of furnaces using immersion heaters for melting. The proposed project can continue if the funding agency resumes the funds to this research. The objective of this project was to develop and demonstrate integrated, retrofitable technologies for clean melting systems for aluminum in both the Metal Casting and integrated aluminum processing industries. The scope focused on immersion heating coupled with metal circulation systems that provide significant opportunity for energy savings as well as reduction of melt loss in the form of dross. The project aimed at the development and integration of technologies that would enable significant reduction in the energy consumption and environmental impacts of melting aluminum through substitution of immersion heating for the conventional radiant burner methods used in reverberatory furnaces. Specifically, the program would couple heater improvements with furnace modeling that would enable cost-effective retrofits to a range of existing furnace sizes, reducing the economic barrier to application.

  6. Analysis of notched metal matrix composites under tensile loading

    NASA Technical Reports Server (NTRS)

    Bigelow, C. A.

    1989-01-01

    This paper presents techniques based on a three-dimensional finite-element analysis for the analysis of continuous fiber reinforced metal matrix composite. Examples are shown for specific metal matrix composites such as boron/aluminum and silicon-carbide/aluminum. Specimen stress-strain behavior and stress at first fiber failure were predicted for boron/aluminum laminates containing circular holes and crack-like slits. The predictions compared very well with test data for laminates containing 0 deg fibers and reasonably well for (+/-45)2s laminates. Mesh configuration was shown to have an effect on the calculation of stresses local to the notch. The presence of thin interface layers of matrix material had a significant influence on the slit tip stress state, causing sharper stress gradients near the notch. Interface layers reduced the slit-tip fibers stress in a (+/-45)2s silicon-carbide/aluminum laminate but increased them in a (0/90)2s laminate.

  7. Characterization of Metal Matrix Composites

    NASA Technical Reports Server (NTRS)

    Daniel, I. M.; Chun, H. J.; Karalekas, D.

    1994-01-01

    Experimental methods were developed, adapted, and applied to the characterization of a metal matrix composite system, namely, silicon carbide/aluminim (SCS-2/6061 Al), and its constituents. The silicon carbide fiber was characterized by determining its modulus, strength, and coefficient of thermal expansion. The aluminum matrix was characterized thermomechanically up to 399 C (750 F) at two strain rates. The unidirectional SiC/Al composite was characterized mechanically under longitudinal, transverse, and in-plane shear loading up to 399 C (750 F). Isothermal and non-isothermal creep behavior was also measured. The applicability of a proposed set of multifactor thermoviscoplastic nonlinear constitutive relations and a computer code was investigated. Agreement between predictions and experimental results was shown in a few cases. The elastoplastic thermomechanical behavior of the composite was also described by a number of new analytical models developed or adapted for the material system studied. These models include the rule of mixtures, composite cylinder model with various thermoelastoplastic analyses and a model based on average field theory. In most cases satisfactory agreement was demonstrated between analytical predictions and experimental results for the cases of stress-strain behavior and thermal deformation behavior at different temperatures. In addition, some models yielded detailed three-dimensional stress distributions in the constituents within the composite.

  8. Energy absorption mechanisms during crack propagation in metal matrix composites

    NASA Technical Reports Server (NTRS)

    Murphy, D. P.; Adams, D. F.

    1979-01-01

    The stress distributions around individual fibers in a unidirectional boron/aluminum composite material subjected to axial and transverse loadings are being studied utilizing a generalized plane strain finite element analysis. This micromechanics analysis was modified to permit the analysis of longitudinal sections, and also to incorporate crack initiation and propagation. The analysis fully models the elastoplastic response of the aluminum matrix, as well as temperature dependent material properties and thermal stress effects. The micromechanics analysis modifications are described, and numerical results are given for both longitudinal and transverse models loaded into the inelastic range, to first failure. Included are initially cracked fiber models.

  9. PREPARATION OF DIBASIC ALUMINUM NITRATE

    DOEpatents

    Gresky, A.T.; Nurmi, E.O.; Foster, D.L.; Wischow, R.P.; Savolainen, J.E.

    1960-04-01

    A method is given for the preparation and recovery of basic aluminum nltrates having an OH: Al ratio of at least two, comprising two steps. First, metallic aluminum is dissolved in aqueous Al(NO/sub 3/)/sub 3/, in the presence of a small quantity of elemental or ionic mercury, to increase its Al: NO/sub 3/ ratio into the range 1 to 1.2. The resulting aqueous solution is then added to an excess of a special organic solvent, typically a mixture of five parts methanol and six parts diethyl ether, whereupon the basic aluminum nitrate, e.g. Al/sub 6/(OH)/sub 13/-(NO/sub 3/)/sub 5/, recoverably precipitates.

  10. Rechargeable Aluminum-Ion Batteries

    SciTech Connect

    Paranthaman, Mariappan Parans; Liu, Hansan; Sun, Xiao-Guang; Dai, Sheng; Brown, Gilbert M

    2015-01-01

    This chapter reports on the development of rechargeable aluminum-ion batteries. A possible concept of rechargeable aluminum/aluminum-ion battery based on low-cost, earth-abundant Al anode, ionic liquid EMImCl:AlCl3 (1-ethyl-3-methyl imidazolium chloroaluminate) electrolytes and MnO2 cathode has been proposed. Al anode has been reported to show good reversibility in acid melts. However, due to the problems in demonstrating the reversibility in cathodes, alternate battery cathodes and battery concepts have also been presented. New ionic liquid electrolytes for reversible Al dissolution and deposition are needed in the future for replacing corrosive EMImCl:AlCl3 electrolytes.

  11. Thermal conductance of augmented pressed metallic contacts at liquid helium temperatures

    NASA Technical Reports Server (NTRS)

    Salerno, L. J.; Kittel, P.; Spivak, A. L.

    1992-01-01

    The thermal conductance of uncoated oxygen-free high conductivity (OFHC) copper, 6061-T6 aluminum, free-machining brass, and 304 stainless steel sample pairs which were augmented with a gold coated 6061-T6 aluminum washer inserted between the contact surfaces was measured over the temperature range of 1.6 to 6.0 K, with applied forces from 22 to 670 N. The contact surfaces of the sample pairs were prepared with a 0.8 micron lapped finish, while the finish of the aluminum washer was 0.2 micron lapped. The contribution to the overall thermal impedance by the bulk conductance of the aluminum washer was negligible. It was found that addition of the washer offered no significant conductance improvement over an uncoated single contact pair; any benefits from using the gold plated washer were counteracted by the addition of two more contact surfaces. Additionally, the thermal conductance of a 'combination' aluminum sample pair having one gold coated and one uncoated surface was measured and compared to the washer pair. The ratio of the conductance of the washer pair to half the conductance of the 'combination' pair was found to be constant and near unity over the temperature range of the data obtained, within experimental error.

  12. Recycling of aluminum salt cake

    SciTech Connect

    Jody, B.J.; Daniels, E.J.; Bonsignore, P.V.; Karvelas, D.E.

    1991-12-01

    The secondary aluminum industry generates more than 110 {times} 10{sup 3} tons of salt-cake waste every year. This waste stream contains about 3--5% aluminum, 15--30% aluminum oxide, 30--40% sodium chloride, and 20--30% potassium chloride. As much as 50% of the content of this waste is combined salt (sodium and potassium chlorides). Salt-cake waste is currently disposed of in conventional landfills. In addition, over 50 {times} 10{sup 3} tons of black dross that is not economical to reprocess a rotary furnace for aluminum recovery ends up in landfills. The composition of the dross is similar to that of salt cake, except that it contains higher concentrations of aluminum (up to 20%) and correspondingly lower amounts of salts. Because of the high solubility of the salts in water, these residues, when put in landfills, represent a potential source of pollution to surface-water and groundwater supplies. The increasing number of environmental regulations on the generation and disposal of industrial wastes are likely to restrict the disposal of these salt-containing wastes in conventional landfills. Processes exist that employ the dissolution and recovery of the salts from the waste stream. These wet-processing methods are economical only when the aluminum concentration in that waste exceeds about 10%. Argonne National Laboratory (ANL) conducted a study in which existing technologies were reviewed and new concepts that are potentially more cost-effective than existing processes were developed and evaluated. These include freeze crystallization, solvent/antisolvent extraction, common-ion effect, high-pressure/high-temperature process, and capillary-effect systems. This paper presents some of the technical and economic results of the aforementioned ANL study.

  13. Metal matrix composites for aircraft propulsion systems

    NASA Technical Reports Server (NTRS)

    Signorelli, R. A.

    1975-01-01

    Studies of advanced aircraft propulsion systems have indicated that performance gains and operating costs are possible through the application of metal matrix composites. Compressor fan blades and turbine blades have been identified as components with high payoff potential as a result of these studies. This paper will present the current status of development of five candidate materials for such applications. Boron fiber/aluminum, boron fiber/titanium, and silicon carbide fiber/titanium composites are considered for lightweight compressor fan blades. Directionally solidified eutectic superalloy and tungsten wire/superalloy composites are considered for application to turbine blades for use temperatures to 1100 C (2000 F).

  14. Elevated temperature crack growth in aluminum alloys: Tensile deformation of 2618 and FVS0812 aluminum alloys

    NASA Technical Reports Server (NTRS)

    Leng, Yang; Gangloff, Richard P.

    1990-01-01

    Understanding the damage tolerance of aluminum alloys at elevated temperatures is essential for safe applications of advanced materials. The objective of this project is to investigate the time dependent subcritical cracking behavior of powder metallurgy FVS0812 and ingot metallurgy 2618 aluminum alloys at elevated temperatures. The fracture mechanics approach was applied. Sidegrooved compact tension specimens were tested at 175, 250, and 316 C under constant load. Subcritical crack growth occurred in each alloy at applied stress intensity levels (K) of between about 14 and 25 MPa/m, well below K (sub IC). Measured load, crack opening displacement and displacement rate, and crack length and growth rate (da/dt) were analyzed with several continuum fracture parameters including, the C-integral, C (sub t), and K. Elevated temperature growth rate data suggest that K is a controlling parameter during time dependent cracking. For FVS0812, da/dt is highest at 175 C when rates are expressed as a function of K. While crack growth rate is not controlled by C (sub t) at 175 C, da/dt appears to better correlate with C (sub t) at higher temperatures. Creep brittle cracking at intermediate temperatures, and perhaps related to strain aging, is augmented by time dependent transient creep plasticity at higher temperatures. The C (sub t) analysis is, however, complicated by the necessity to measure small differences in the elastic crack growth and creep contributions to the crack opening displacement rate. A microstructural study indicates that 2618 and FVS0812 are likely to be creep brittle materials, consistent with the results obtained from the fracture mechanics study. Time dependent crack growth of 2618 at 175 C is characterized by mixed transgranular and intergranular fracture. Delamination along the ribbon powder particle boundaries occurs in FVS0812 at all temperatures. The fracture mode of FVS0812 changes with temperature. At 175 C, it is characterized as dimpled rupture

  15. Aluminum-air battery crystallizer

    SciTech Connect

    Maimoni, A.

    1987-01-23

    A prototype crystallizer system for the aluminum-air battery operated reliably through simulated startup and shutdown cycles and met its design objectives. The crystallizer system allows for crystallization and removal of the aluminium hydroxide reaction product; it is required to allow steady-state and long-term operation of the aluminum-air battery. The system has to minimize volume and maintain low turbulence and shear to minimize secondary nucleation and energy consumption while enhancing agglomeration. A lamella crystallizer satisfies system constraints.

  16. Aluminum-carbon composite electrode

    DOEpatents

    Farahmandi, C.J.; Dispennette, J.M.

    1998-07-07

    A high performance double layer capacitor having an electric double layer formed in the interface between activated carbon and an electrolyte is disclosed. The high performance double layer capacitor includes a pair of aluminum impregnated carbon composite electrodes having an evenly distributed and continuous path of aluminum impregnated within an activated carbon fiber preform saturated with a high performance electrolytic solution. The high performance double layer capacitor is capable of delivering at least 5 Wh/kg of useful energy at power ratings of at least 600 W/kg. 3 figs.

  17. Aluminum-carbon composite electrode

    DOEpatents

    Farahmandi, C. Joseph; Dispennette, John M.

    1998-07-07

    A high performance double layer capacitor having an electric double layer formed in the interface between activated carbon and an electrolyte is disclosed. The high performance double layer capacitor includes a pair of aluminum impregnated carbon composite electrodes having an evenly distributed and continuous path of aluminum impregnated within an activated carbon fiber preform saturated with a high performance electrolytic solution. The high performance double layer capacitor is capable of delivering at least 5 Wh/kg of useful energy at power ratings of at least 600 W/kg.

  18. Hermetically sealed aluminum electrolytic capacitor

    NASA Technical Reports Server (NTRS)

    Alwitt, Robert S.; Liu, Yanming; Elias, William

    1995-01-01

    Aluminum electrolytic capacitors are presently not allowed on NASA missions because they outgas water and organic vapors, as well as H2. As a consequence, much larger and heavier packages of tantalum capacitors are used. A hermetically sealed aluminum capacitor has been developed under NASA-MSFC SBIR contracts. This capacitor contains a nongassing electrolyte that was developed for this application so internal pressure would remain low. Capacitors rated at 250 to 540 V have been operated under full load for thousands of hours at 85 and 105 C with good electrical performance and low internal pressure. Electrolyte chemistry and seal engineering concepts will be discussed.

  19. Dissolution and Separation of Aluminum and Aluminosilicates

    DOE PAGESBeta

    McFarlane, Joanna; Benker, Dennis; DePaoli, David W.; Felker, Leslie Kevin; Mattus, Catherine H.

    2015-12-19

    The selection of an aluminum alloy for target irradiation affects post-irradiation target dissolution and separations. Recent tests with aluminum alloy 6061 yielded greater than expected precipitation in the dissolver, forming up to 10 wt.% solids of aluminum hydroxides and aluminosilicates. Aluminosilicate dissolution presents challenges in a number of different areas, metals extraction from minerals, flyash treatment, and separations from aluminum alloys. We present experimental work that attempts to maximize dissolution of aluminum metal, along with silicon, magnesium, and copper impurities, through control of temperature, the rate of reagent addition, and incubation time. Aluminum phase transformations have been identified as amore » function of time and temperature, using X-ray diffraction. Solutions have been analyzed using wet chemical methods and X-ray fluorescence. Our data have been compared with published calculations of aluminum phase diagrams. Approaches are given to enhance the dissolution of aluminum and aluminosilicate phases in caustic solution.« less

  20. Dissolution and Separation of Aluminum and Aluminosilicates

    SciTech Connect

    McFarlane, Joanna; Benker, Dennis; DePaoli, David W.; Felker, Leslie Kevin; Mattus, Catherine H.

    2015-12-19

    The selection of an aluminum alloy for target irradiation affects post-irradiation target dissolution and separations. Recent tests with aluminum alloy 6061 yielded greater than expected precipitation in the dissolver, forming up to 10 wt.% solids of aluminum hydroxides and aluminosilicates. Aluminosilicate dissolution presents challenges in a number of different areas, metals extraction from minerals, flyash treatment, and separations from aluminum alloys. We present experimental work that attempts to maximize dissolution of aluminum metal, along with silicon, magnesium, and copper impurities, through control of temperature, the rate of reagent addition, and incubation time. Aluminum phase transformations have been identified as a function of time and temperature, using X-ray diffraction. Solutions have been analyzed using wet chemical methods and X-ray fluorescence. Our data have been compared with published calculations of aluminum phase diagrams. Approaches are given to enhance the dissolution of aluminum and aluminosilicate phases in caustic solution.

  1. Nitriding of large-sized aluminum

    SciTech Connect

    Ito, Shigeru; Yoshida, Kazuharu; Sato, Shin-ichi

    1996-06-01

    Aluminum chips with 2mm in size have been successfully nitrided with 99.3% of conversion, using yttrium oxide as a promoter. The product consisted of hollow spheres with 2mm in dia. and fine particles of aluminum nitride. This nitriding is divided into two steps. In the first step, nitriding begins from the surface of aluminum chip. Because the surface is activated by the addition of yttrium oxide, the reaction heat raises the temperature of aluminum enough to generate the aluminum vapor, followed by the second step; exothermic reaction of aluminum vapor and nitrogen gas. In addition, to accelerate the first step without additive, electrolytic etching was applied to aluminum wires with 2mm in dia. In this case, aluminum wires were also completely nitrided.

  2. Aluminum: World market prospects for troubled times

    NASA Astrophysics Data System (ADS)

    Djukanovic, Goran

    2009-02-01

    Aluminum and alumina prices and production volumes dropped significantly in 2008 due to the worldwide economic recession. This paper provides a comprehensive analysis of the current state of the aluminum industry and its outlook for the future.

  3. Aluminum nitride insulating films for MOSFET devices

    NASA Technical Reports Server (NTRS)

    Lewicki, G. W.; Maserjian, J.

    1972-01-01

    Application of aluminum nitrides as electrical insulator for electric capacitors is discussed. Electrical properties of aluminum nitrides are analyzed and specific use with field effect transistors is defined. Operational limits of field effect transistors are developed.

  4. 75 FR 70689 - Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum-Greenwood Forge Division; Currently...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-18

    ... in the Federal Register on November 17, 2009 (74 FR 59254). At the request of the State agency and a... Employment and Training Administration Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum- Greenwood... Aluminum Fabricated Products, LLC, Kaiser Aluminum-Greenwood Forge Division, including on- site...

  5. The effect of zinc on the aluminum anode of the aluminum-air battery

    NASA Astrophysics Data System (ADS)

    Tang, Yougen; Lu, Lingbin; Roesky, Herbert W.; Wang, Laiwen; Huang, Baiyun

    Aluminum is an ideal material for batteries, due to its excellent electrochemical performance. Herein, the effect of zinc on the aluminum anode of the aluminum-air battery, as an additive for aluminum alloy and electrolytes, has been studied. The results show that zinc can decrease the anodic polarization, restrain the hydrogen evolution and increase the anodic utilization rate.

  6. [Determination of Arsenic in Food Package Aluminum by Ultrasound Assisted Solid Phase Extraction/ICP-AES].

    PubMed

    Qin, Wen-xia; Gong, Qi; Li, Min; Deng, Li-xin; Mo, Li-shu; Li, Yan-lin

    2015-04-01

    Determination of arsenic in pure aluminum by inductively coupled plasma atomic emission spectrometry was interfered by aluminum matrix. The experiment showed that when the mass concentration of Al was greater than or equal to 5 000 times the As in the test solution, the measurement error was greater than 5%. In order to eliminate the interference, strong acid cation exchange fiber (SACEF) was used as solid phase extraction agent to adsorb Al(3+). The extraction conditions included amount of SACEF, extraction time, temperature and pH were investigated. The optimal extraction conditions were that 0.9000 g SACEF was used to extract the aluminum from the sample solution of pH 2.0 at 55 °C for 5 min with the ultrasonic assist, and in this case, the arsenic in the form of arsenic acid was not extracted and left in the solution for the determination. The results showed that after treating 10. 00 mL test solution containing 1.00 µg arsenic and 20.0 mg aluminum, arsenic did not lose. The mass concentration of residual aluminum in the raffinate was about 2,000 times the As, which had not interfered the determination of arsenic. The detection limit (3 s) was 0.027 µg · mL(-1) and quantification limit (10 s) was 0.0091 µg · mL(-1). The proposed method was successfully applied to the separation and determination of arsenic in the synthetic samples, the aluminum cans and the barbecue aluminum foil. Recovery was in the range of 98.3%-105% and RSD (n = 3) was in the range of 0.1%-4.3%. The results showed that the content of arsenic in the aluminum cans and the aluminum barbecue foil was below the limited value of national standard (GB/T 3190-2008). PMID:26197599

  7. RECOVERY OF ALUMINUM FROM FISSION PRODUCTS

    DOEpatents

    Blanco, R.E.; Higgins, I.R.

    1962-11-20

    A method is given for recovertng aluminum values from aqueous solutions containing said values together with fission products. A mixture of Fe/sub 2/O/ sub 3/ and MnO/sub 2/ is added to a solution containing aluminum and fission products. The resulting aluminum-containing supernatant is then separated from the fission product-bearing metal oxide precipitate and is contacted with a cation exchange resin. The aluminum sorbed on the resin is then eluted and recovered. (AEC)

  8. Mineral resource of the month: aluminum

    USGS Publications Warehouse

    Bray, E. Lee

    2012-01-01

    The article offers information on aluminum, a mineral resource which is described as the third-most abundant element in Earth's crust. According to the article, aluminum is the second-most used metal. Hans Christian Oersted, a Danish chemist, was the first to isolate aluminum in the laboratory. Aluminum is described as lightweight, corrosion-resistant and an excellent conductor of electricity and heat.

  9. A macro-micromechanics analysis of a notched metal matrix composite

    NASA Technical Reports Server (NTRS)

    Bigelow, Catherine A.; Naik, Rajiv A.

    1992-01-01

    Macro- and micromechanics analysis were conducted to determine the matrix and fiber behaviors near the notch in a center-notched metal-matrix composite. In this approach, the macrolevel analysis models the entire notched specimen using a 3D finite element program that uses the vanishing-fiber-diameter model to simulate the elastic-plastic behavior of the matrix and the elastic behavior of the fiber. The microlevel behavior is analyzed using a discrete fiber-matrix model containing one fiber and the surrounding matrix. The viability of this analysis is demonstrated using results for a boron/aluminum monolayer.

  10. Blood aluminum levels as a function of aluminum intake from drinking water

    SciTech Connect

    Turnquest, E.M.; Hallenbeck, W.H. )

    1991-04-01

    Questions regarding the health effects of aluminum are still unanswered. The speciation, pharmacokinetics, and toxicity of aluminum are not well understood. Furthermore, no animal or human studies of aluminum absorption have been reported using drinking water as the source of aluminum. The following experiment attempted to reach a better understanding of the bioavailability of aluminum from drinking water. Its objective was to determine whether or not increased aluminum ingestion from drinking water would be reflected in increased serum and whole blood aluminum levels in the baboon experimental model.

  11. Low cycle fatigue behavior of aluminum/stainless steel composites

    NASA Technical Reports Server (NTRS)

    Bhagat, R. B.

    1983-01-01

    Composites consisting of an aluminum matrix reinforced with various volume fractions of stainless steel wire were fabricated by hot die pressing under various conditions of temperature, time, and pressure. The composites were tested in plane bending to complete fracture under cycle loading, and the results were analyzed on a computer to obtain a statistically valid mathematical relationship between the low-cycle fatigue life and the fiber volume fraction of the composite. The fractured surfaces of the composites were examined by scanning electron microscopy to identify the characteristic features of fatigue damage. Fatigue damage mechanisms are proposed and discussed.

  12. Electronic and magnetic properties of manganese impurities in aluminum

    NASA Astrophysics Data System (ADS)

    Bagayoko, D.; Brener, N.; Kanhere, D.; Callaway, J.

    1987-12-01

    We studied the electronic structure of manganese impurities in a fcc aluminum matrix by means of calculations for a free MnAl18 cluster. Our ab initio self-consistent computations employed the Rajagopal-Singhal-Kimball local-spin-density potential and a symmetrized Gaussian-orbital basis. The local and cluster magnetic moments are, respectively, 1.74μB and 1.0μB. Substantial screening of the Mn moment by opposite polarization of the surrounding Al atoms was found.

  13. Dynamic consolidation of aluminum-silicon carbide composites

    SciTech Connect

    Rabin, B.H.; Korth, G.E.; Williamson, R.L.

    1990-01-01

    Dynamic consolidation was investigated as a potential method for producing P/M metal matrix composites. In this study, 2124 aluminum powders were mixed with silicon carbide particulate and consolidated using explosives. Numerical simulations were performed to provide insight into the consolidation process and to aid in the selection of experimental conditions. The microstructure of the as-consolidated product was dependent upon processing variables. Careful control of the shock parameters allowed full density, crack free composites to be achieved in cylindrical geometries. Although full density was obtained, low fracture strengths suggested a lack of interparticle bonding, probably resulting from the limited ability to redistribute surface oxides during consolidation. 10 refs., 9 figs.

  14. Novel aqueous aluminum/sulfur batteries

    SciTech Connect

    Licht, S.; Peramunage, D. )

    1993-01-01

    Aluminum sulfur batteries based on concentrated polysulfide catholytes and an alkaline aluminum anode are introduced and investigated. The new battery is expressed by aluminum oxidation and aqueous sulfur reduction for an overall battery discharge consisting of 2Al + S[sub 4][sup 2[minus

  15. 21 CFR 73.2645 - Aluminum powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Aluminum powder. 73.2645 Section 73.2645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2645 Aluminum powder. (a) Identity and specifications. The color additive aluminum powder shall conform in identity and specifications to the requirements...

  16. 21 CFR 182.1125 - Aluminum sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Aluminum sulfate. 182.1125 Section 182.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  17. 21 CFR 172.310 - Aluminum nicotinate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Aluminum nicotinate. 172.310 Section 172.310 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Special Dietary and Nutritional Additives § 172.310 Aluminum nicotinate. Aluminum nicotinate may be...

  18. 21 CFR 172.310 - Aluminum nicotinate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Aluminum nicotinate. 172.310 Section 172.310 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Special Dietary and Nutritional Additives § 172.310 Aluminum nicotinate. Aluminum nicotinate may be...

  19. 21 CFR 182.1125 - Aluminum sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Aluminum sulfate. 182.1125 Section 182.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  20. 21 CFR 582.1125 - Aluminum sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Aluminum sulfate. 582.1125 Section 582.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  1. 21 CFR 582.1125 - Aluminum sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Aluminum sulfate. 582.1125 Section 582.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  2. 21 CFR 172.310 - Aluminum nicotinate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Aluminum nicotinate. 172.310 Section 172.310 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Additives § 172.310 Aluminum nicotinate. Aluminum nicotinate may be safely used as a source of niacin...

  3. 21 CFR 182.1125 - Aluminum sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Aluminum sulfate. 182.1125 Section 182.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  4. 21 CFR 582.1125 - Aluminum sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Aluminum sulfate. 582.1125 Section 582.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  5. 21 CFR 582.1125 - Aluminum sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Aluminum sulfate. 582.1125 Section 582.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  6. 21 CFR 582.1125 - Aluminum sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Aluminum sulfate. 582.1125 Section 582.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  7. 21 CFR 172.310 - Aluminum nicotinate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Aluminum nicotinate. 172.310 Section 172.310 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Special Dietary and Nutritional Additives § 172.310 Aluminum nicotinate. Aluminum nicotinate may be...

  8. 21 CFR 182.1125 - Aluminum sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Aluminum sulfate. 182.1125 Section 182.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  9. 21 CFR 73.2645 - Aluminum powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Aluminum powder. 73.2645 Section 73.2645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2645 Aluminum powder. (a) Identity and specifications. The color additive aluminum powder shall conform in identity and specifications to the requirements...

  10. 21 CFR 182.1125 - Aluminum sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Aluminum sulfate. 182.1125 Section 182.1125 Food... GENERALLY RECOGNIZED AS SAFE Multiple Purpose GRAS Food Substances § 182.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This substance is generally recognized as safe when used...

  11. 21 CFR 172.310 - Aluminum nicotinate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Aluminum nicotinate. 172.310 Section 172.310 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Special Dietary and Nutritional Additives § 172.310 Aluminum nicotinate. Aluminum nicotinate may be...

  12. 21 CFR 73.2645 - Aluminum powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Aluminum powder. 73.2645 Section 73.2645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2645 Aluminum powder. (a) Identity and specifications. The color additive aluminum powder shall conform in identity and specifications to the requirements...

  13. 75 FR 80527 - Aluminum Extrusions From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-22

    ... Affirmative Countervailing Duty Determination, 75 FR 54302, September 7, 2010, and Aluminum Extrusions From... Antidumping Duty Determination, 75 FR 57441, September 21, 2010. \\3\\ See Aluminum Extrusions From the People's... Determination of Targeted Dumping, 75 FR 69403, November 12, 2010, and Aluminum Extrusions From the...

  14. [Current researches on biological effect of aluminum].

    PubMed

    Wang, Jin

    2002-08-01

    Aluminum content is generally not high (less that 10 mg/kg) in most foods with the exception of a few such as tea, spinach, and so on, that contain more amounts of it. However, aluminum content is much high in foods in those aluminum-containing food additives are used. After drinking water is treated with aluminum-containing coagulant agent, it's aluminum concentration increases. The aluminum intake of residents from cookware in our country is 4 mg/(capit.d). The aluminum intake in adults is usually 10 mg/(capit.d), but it will rise up to tens to hundreds mg/(capit.d) when residents consume foods with a high aluminum concentration or aluminum-containing drugs. Aluminum is absorbed mainly via a duodenum, and this can be influenced by multiple factors. Absorbed aluminum is discharged primarily by renal excretion. Aluminum accumulation in human body might harm central nervous system, bone lesions, and hemopoietic system, and is a suspected causal factor to Alzheimer's disease. PMID:12600050

  15. 21 CFR 73.2645 - Aluminum powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Aluminum powder. 73.2645 Section 73.2645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2645 Aluminum powder. (a) Identity and specifications. The color additive aluminum powder shall conform in identity and specifications to the requirements...

  16. 21 CFR 73.2645 - Aluminum powder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Aluminum powder. 73.2645 Section 73.2645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2645 Aluminum powder. (a) Identity and specifications. The color additive aluminum powder shall conform in identity and specifications to the requirements...

  17. Thermal conductance of gold plated metallic contacts at liquid helium temperatures

    NASA Technical Reports Server (NTRS)

    Kittel, Peter; Spivak, Alan L.; Salerno, Louis J.

    1992-01-01

    The thermal conductance of gold plated OFHC copper, 6061-T6 aluminum, free-machining brass, and 304 stainless steel contacts has been measured over the temperature range of 1.6 to 4.2 K, with applied forces from 22 N to 670 N. The contact surfaces were prepared with a 0.8 micron lapped finish prior to gold coating. It was found that for all materials, except stainless steel, the thermal conductance was significantly improved as the result of gold coating the contact surfaces.

  18. Small screw study: Interim report on fastener tensile strength and optimum thread depth

    SciTech Connect

    Diegert, K.V.; Dorrell, L.R.; Reese, R.T.; Lazarus, L.J.; Allied-Signal Aerospace Co., Kansas City, MO . Kansas City Div.)

    1989-10-01

    This report summarizes about 1260 tests performed on small threaded fasteners (equal to or less than 1/4 inch in diameter and designated as 1/4-20 UNC, {number sign}4-40 UNC, {number sign}2-56 UNC, and 1.0 UNM). Tests determined the tensile strengths of the screws, the lengths of engagement needed to develop the full tensile strengths when the screws were engaged in 6061-T6 Aluminum, Hiperco 50, and 303 Stainless Steel, and whether relationships existed between the tensile strengths and Knoop Micro-Hardness measurements taken on the threaded ends of the screws. 17 figs., 13 tabs.

  19. Engineering of the Stellarator of Costa Rica: SCR-1

    NASA Astrophysics Data System (ADS)

    Mora, J.; Vargas, V. I.; Otarola, C.; Piedra, C.; Jimenez, W.; Esquivel, L.; Esquivel, R.; Sanchez, K.; Gonzalez, J.; Asenjo, J.; Fonseca, L.

    2015-03-01

    This Paper aims at briefly describing the challenge of the design and construction of the Stellarator of Costa Rica 1 (SCR-1) [1]. The SCR-1 is a small modular Stellarator for magnetic confinement of plasma (Ro=0.238 m, =0.059 m, Ro/a>4.0, expected plasma volume ≈ 0.016 m3, 10 mm thickness 6061-T6 aluminum vacuum vessel) developed by the Plasma Laboratory for Fusion Energy and Applications of the Instituto Tecnológico de Costa Rica (ITCR).

  20. Electron beam weld development on a Filter Pack Assembly. Final report

    SciTech Connect

    Dereskiewicz, J.P.

    1994-06-01

    A continuous electron beam welding procedure was developed to replace the manual gas tungsten arc welding procedure on the Filter Pack Assembly. A statistical study was used to evaluate the feasibility of electron beam welding 6061-T6 aluminum covers to A356 cast weldments throughout the joint tolerance range specified on product drawings. Peak temperature exposures were not high enough to degrade the heat sensitive electrical components inside the cast weldment. Actual weldments with alodine coating on the weld joint area were successfully cleaned using a nonmetallic fiberglass brush cleaning method.

  1. Space-based visible all-reflective stray light telescope

    NASA Astrophysics Data System (ADS)

    Wang, Dexter; Gardner, Leo R.; Wong, Wallace K.; Hadfield, Peter

    1991-08-01

    A 6-inch diameter aperture space-based visible telescope has been optimized to perform surveillance against the space background with earth albedo as a primary source of straylight. A three mirror off-axis anastigmat has been designed to cover a 1.4 degree(s) by 6.6 degree(s) field- of-view with 60 (mu) radian spatial resolution. The telescope body and optics are constructed of 6061-T6 aluminum to provide a thermally stable optical system. The optical elements are 'superfinished' to minimize scatter. Extensive baffles and stops are utilized to further reduce straylight. The telescope will be used on the Midcourse Space Experiment platform.

  2. High-speed tapping for N/C machining centers

    SciTech Connect

    Friend, J.P.

    1991-11-01

    Through a series of experiments, a new high-speed tapping technique was developed for N/C machining centers. The new technique produces high quality threads in a fraction of the time previously required, using the same equipment. Threads are produced to precise size and depth in a single pass at speeds up to 5000 rpm. Thread sizes ranged from 0.80 UNM (Unified Miniature Thread Series) (0.0315 in. major diameter) to 0.250-20 UN (Unified Screw Threads) in both blind and through-hole applications. The materials tapped included 17-4 PH stainless steel, 300 series stainless steel, and 6061-T6 aluminum. 10 figs.

  3. Electron beam weld development on a Filter Pack Assembly

    NASA Astrophysics Data System (ADS)

    Dereskiewicz, J. P.

    1994-06-01

    A continuous electron beam welding procedure was developed to replace the manual gas tungsten arc welding procedure on the Filter Pack Assembly. A statistical study was used to evaluate the feasibility of electron beam welding 6061-T6 aluminum covers to A356 cast weldments throughout the joint tolerance range specified on product drawings. Peak temperature exposures were not high enough to degrade the heat sensitive electrical components inside the cast weldment. Actual weldments with alodine coating on the weld joint area were successfully cleaned using a nonmetallic fiberglass brush cleaning method.

  4. Performance characterization of fiber Bragg grating thermal response in space vacuum thermal environment

    NASA Astrophysics Data System (ADS)

    Jiang, Junfeng; Song, Luyao; Liu, Tiegen; Zhang, Jingchuan; Liu, Kun; Wang, Shuang; Yin, Jinde; Zhao, Peng; Xie, Jihui; Wu, Fan; Zhang, Xuezhi

    2013-12-01

    We investigated the fiber Bragg grating (FBG) thermal response in space vacuum thermal environment. The FBGs were packaged with 6061-T6 aluminum. The liquid nitrogen immersion experiment results show that its wavelength shift standard deviation is 0.76 pm for 217 h. The combination effect of vacuum and cryogenic temperature was studied by thermal cycling process in space environment simulator. The FBG sensors show accuracy better than 2% full scale, and the hysteresis errors are below 1%. It proves that these metal packaged FBG sensors can survive and meet the requirement of space measurement.

  5. An ultra-low surface finish process for 6061-Al mirrors

    NASA Astrophysics Data System (ADS)

    Wamboldt, Leonard; Roy, Brian; Crifasi, Joseph; Stephens, Shane; Hanninen, Derek; Woodard, Kenneth; Felock, Robert; Cunha-Vasconcelos, Sofia; Polczwartek, Stephen; Parenteau, Jeffrey

    2015-05-01

    An ultra-low surface finishing process for 6061 T6 type aluminum has been developed by Corning Incorporated, Specialty Materials Division, and has been successfully applied to mirrors up to 13 inches in diameter. This paper presents finish and figure data achieved from the mirror finishing process. Mirror stability is demonstrated through Pre and post thermal cycle surface figure measurements; temperature range of cycle -55°C to +70°C. As an added benefit, the process enables the use of deterministic finishing and enhances the reflective optics resistance to corrosion. Survivability of the reflective optic is evaluated through extended humidity testing.

  6. Thermal conductance of gold plated metallic contacts at liquid helium temperatures

    NASA Astrophysics Data System (ADS)

    Kittel, Peter; Spivak, Alan L.; Salerno, Louis J.

    The thermal conductance of gold plated OFHC copper, 6061-T6 aluminum, free-machining brass, and 304 stainless steel contacts has been measured over the temperature range of 1.6 to 4.2 K, with applied forces from 22 N to 670 N. The contact surfaces were prepared with a 0.8 micron lapped finish prior to gold coating. It was found that for all materials, except stainless steel, the thermal conductance was significantly improved as the result of gold coating the contact surfaces.

  7. Performance characterization of fiber Bragg grating thermal response in space vacuum thermal environment.

    PubMed

    Jiang, Junfeng; Song, Luyao; Liu, Tiegen; Zhang, Jingchuan; Liu, Kun; Wang, Shuang; Yin, Jinde; Zhao, Peng; Xie, Jihui; Wu, Fan; Zhang, Xuezhi

    2013-12-01

    We investigated the fiber Bragg grating (FBG) thermal response in space vacuum thermal environment. The FBGs were packaged with 6061-T6 aluminum. The liquid nitrogen immersion experiment results show that its wavelength shift standard deviation is 0.76 pm for 217 h. The combination effect of vacuum and cryogenic temperature was studied by thermal cycling process in space environment simulator. The FBG sensors show accuracy better than 2% full scale, and the hysteresis errors are below 1%. It proves that these metal packaged FBG sensors can survive and meet the requirement of space measurement. PMID:24387420

  8. Recovering aluminum from aluminum dross in a DC electric-arc rotary furnace

    NASA Astrophysics Data System (ADS)

    Tzonev, Tz.; Lucheva, B.

    2007-11-01

    The recycling of aluminum scrap and dross yields significant economic and energy savings, as well environmental benefits. The recovery of aluminum depends on many factors. The aim of this work is to experimentally investigate aluminum recovery under different conditions. In this study, aluminum dross was processed in a direct-current electric-arc rotary furnace. The presence of crushing refractory bodies during processing was found to increase the degree of aluminum recovery by about ten percent.

  9. Inert anodes for aluminum smelting

    SciTech Connect

    Weyand, J.D.; Ray, S.P.; Baker, F.W.; DeYoung, D.H.; Tarcy, G.P.

    1986-02-01

    The use of nonconsumable or inert anodes for replacement of consumable carbon anodes in Hall electrolysis cells for the production of aluminum has been a technical and commercial goal of the aluminum industry for many decades. This report summarizes the technical success realized in the development of an inert anode that can be used to produce aluminum of acceptable metal purity in small scale Hall electrolysis cells. The inert anode material developed consists of a cermet composition containing the phases: copper, nickel ferrite and nickel oxide. This anode material has an electrical conductivity comparable to anode carbon used in Hall cells, i.e., 150 ohm {sup {minus}1}cm{sup {minus}1}. Metal purity of 99.5 percent aluminum has been produced using this material. The copper metal alloy present in the anode is not removed by anodic dissolution as does occur with cermet anodes containing a metallic nickel alloy. Solubility of the oxide phases in the cryolite electrolyte is reduced by: (1) saturated concentration of alumina, (2) high nickel oxide content in the NiO-NiFe{sub 2}O{sub 4} composition, (3) lowest possible cell operating temperature, (4) additions of alkaline or alkaline earth fluorides to the bath to reduce solubilities of the anode components, and (5) avoiding bath contaminants such as silica. Dissolution rate measurements indicate first-order kinetics and that the rate limiting step for dissolution is mass transport controlled. 105 refs., 234 figs., 73 tabs.

  10. Directly polished lightweight aluminum mirror

    NASA Astrophysics Data System (ADS)

    ter Horst, Rik; Tromp, Niels; de Haan, Menno; Navarro, Ramon; Venema, Lars; Pragt, Johan

    2008-07-01

    During the last ten years, Astron has been a major contractor for the design and manufacturing of astronomical instruments for Space- and Earth based observatories, such as VISIR, MIDI, SPIFFI, X-Shooter and MIRI. The collaboration between optical- and mechanical designers at Astron led to new design philosophies and strategies. Driven by the need to reduce the weight of optically ultra-stiff structures, two promising techniques have been developed in the last years: ASTRON Extreme Lightweighting for mechanical structures and an improved Polishing Technique for Aluminum Mirrors. Using one single material for both optical components and mechanical structure simplifies the design of a cryogenic instrument significantly, it is very beneficial during instrument test and verification, and makes the instrument insensitive to temperature changes. Aluminum has been the main material used for cryogenic optical instruments, and optical aluminum mirrors are generally diamond turned. The application of a polishable hard top coating like nickel removes excess stray light caused by the groove pattern, but limits the degree of lightweighting of the mirrors due to the bi-metal effect. By directly polishing the aluminum mirror surface, the recent developments at Astron allow for using a non-exotic material for light weighted yet accurate optical mirrors, with a lower surface roughness (~1nm RMS), higher surface accuracy and reduced light scattering. This paper presents the techniques, obtained results and a global comparison with alternative lightweight mirror solutions.

  11. Aluminum: The Next Twenty Years

    NASA Astrophysics Data System (ADS)

    Fitzgerald, M. Desmond; Pollio, Gerald

    1982-12-01

    This report concludes that the outlook for the world aluminum industry is quite favorable. Demand is expected to expand at a more rapid rate than for other basic metals, but not sufficiently to put undue strain on productive capacity. Capital requirements of the world aluminum industry are projected at 95.5 billion in 1980 prices — more than 200 billion in current prices—over the balance of the century. Given the aluminum industry's past success in generating internal funds, this level of capital expanditure should not cause undue financing problems. Finally, we expect changes to occur in the structure of the industry over the forecast period, with virtually all new alumina capacity being installed in proximity to bauxite production, and—with the exception of Australia—a major shift in smelting capacity away from other industrialized economies. While the large multinational companies will still play a dominant role in the world aluminum market, their share of production and ownership is likely to decline progressively during the period.

  12. Characterizatin of ultrafine aluminum nanoparticles

    SciTech Connect

    Sandstrom, M. M.; Jorgensen, B. S.; Mang, J. T.; Smith, B. L.; Son, S. F.

    2004-01-01

    Aluminum nanopowders with particle sizes ranging from {approx}25 nm to 80 nm were characterized by a variety of methods. We present and compare the results from common powder characterization techniques including transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), BET gas adsorption surface area analysis, thermogravimetric analysis (TGA), photon correlation spectroscopy (PCS), and low angle laser light scattering (LALLS). Aluminum nanoparticles consist of an aluminum core with an aluminum oxide coating. HRTEM measurements of both the particle diameter and oxide layer thickness tend to be larger than those obtained from BET and TGA. LALLS measurements show a large degree of particle agglomeration in solution; therefore, primary particle sizes could not be determined. Furthermore, results from small-angle scattering techniques (SAS), including small-angle neutron (SANS) and x-ray (SAXS) scattering are presented and show excellent agreement with the BET, TGA, and HRTEM. The suite of analytical techniques presented in this paper can be used as a powerful tool in the characterization of many types of nanosized powders.

  13. Aluminum and its light alloys

    NASA Technical Reports Server (NTRS)

    Merica, Paul D

    1920-01-01

    Report is a summary of research work which has been done here and abroad on the constitution and mechanical properties of the various alloy systems with aluminum. The mechanical properties and compositions of commercial light alloys for casting, forging, or rolling, obtainable in this country are described.

  14. A matrix lower bound

    SciTech Connect

    Grcar, Joseph F.

    2002-02-04

    A matrix lower bound is defined that generalizes ideas apparently due to S. Banach and J. von Neumann. The matrix lower bound has a natural interpretation in functional analysis, and it satisfies many of the properties that von Neumann stated for it in a restricted case. Applications for the matrix lower bound are demonstrated in several areas. In linear algebra, the matrix lower bound of a full rank matrix equals the distance to the set of rank-deficient matrices. In numerical analysis, the ratio of the matrix norm to the matrix lower bound is a condition number for all consistent systems of linear equations. In optimization theory, the matrix lower bound suggests an identity for a class of min-max problems. In real analysis, a recursive construction that depends on the matrix lower bound shows that the level sets of continuously differential functions lie asymptotically near those of their tangents.

  15. Nanoscale lead and noble gas inclusions in aluminum: structures and properties.

    PubMed

    Johnson, Erik; Andersen, Hans Henrik; Dahmen, Ulrich

    2004-08-01

    Transmission electron microscopy has been used for structural and physical characterization of nanoscale inclusions of lead and noble gases in aluminum. When the inclusion sizes approach nanoscale dimensions, many of their properties are seen to deviate from similar properties in bulk and in most cases the deviations will increase as the inclusion sizes decrease. Binary alloys of lead and noble gases with aluminum are characterized by extremely low mutual solubilities and inclusions will, therefore, exist as practically pure components embedded in the aluminum matrix. Furthermore, the thermal vacancy mobility in aluminum at and above room temperature is sufficiently high to accommodate volume strains associated with the inclusions thus leading to virtually strain free crystals. The inclusions grow in parallel cube alignment with the aluminum matrix and have a cuboctahedral shape, which reflects directly the anisotropy of the interfacial energies. Inclusions in grain boundaries can have single crystalline or bicrystalline morphology that can be explained from a generalized Wulff analysis such as the xi-vector construction. The inclusions have been found to display a variety of nanoscale features such as high Laplace pressure, size-dependent superheating during melting, deviations from the Wulff shape displaying magic size effects, a shape dependence of edge energy, and so on. All these effects have been observed and monitored by TEM using conventional imaging conditions and high-resolution conditions in combination with in-situ analysis at elevated temperatures. PMID:15549703

  16. Solidification processing of monotectic alloy matrix composites

    NASA Technical Reports Server (NTRS)

    Frier, Nancy L.; Shiohara, Yuh; Russell, Kenneth C.

    1989-01-01

    Directionally solidified aluminum-indium alloys of the monotectic composition were found to form an in situ rod composite which obeys a lambda exp 2 R = constant relation. The experimental data shows good agreement with previously reported results. A theoretical boundary between cellular and dendritic growth conditions was derived and compared with experiments. The unique wetting characteristics of the monotectic alloys can be utilized to tailor the interface structure in metal matrix composites. Metal matrix composites with monotectic and hypermonotectic Al-In matrices were made by pressure infiltration, remelted and directionally solidified to observe the wetting characteristics of the alloys as well as the effect on structure of solidification in the constrained field of the fiber interstices. Models for monotectic growth are modified to take into account solidification in these constrained fields.

  17. Computational modeling of thin ceramic tiles backed by thin substrates

    SciTech Connect

    Walker, J.D.; Anderson, C.E. Jr.; Cox, P.A.

    1995-12-31

    Building on the work of Wilkins, Eulerian hydrocode calculations were performed with ceramic models to examine the behavior of thin ceramic tiles backed by a thin substrate. In order to match ballistic limit data it was necessary to include a pressure dependent flow stress for failed ceramic. Reasonable agreement is found between the modified model and ballistic limit data for a simulated armor piercing round impacting an AD-85 alumina/6061T6 aluminum laminate. Based upon this success, the modified model was used to examine the performance of a SiC/6061T6 aluminum laminate when impacted by an M80 ball round (7.62 mm) at muzzle velocity. The projectile undergoes large deformation, as does the aluminum backing sheet. The computational results indicate, for the M80 projectile impacting at muzzle velocity, that the ballistic limit thickness for the SiC/aluminum laminate should weigh 10% less than the ballistic limit thickness for steel. The talk will include a video tape of calculations.

  18. Infiltration kinetics and interfacial bond strength of metal-matrix composites. Final report

    SciTech Connect

    Edwards, G.R.; Olson, D.L.

    1992-07-01

    The research accomplishments for this three-year metal matrix composite research program centered upon three areas: infiltration kinetics, wettability studies and predictions of interfacial properties. A pre-conditioning reaction model was hypothesized to explain the incubation period observed to precede the liquid metal infiltration of SiC particulate, and a rate equation for pre-conditioning was experimentally established for the infiltration of SiC particulate by liquid aluminum. Experimental wettability studies were completed for aluminum--silicon, aluminum--magnesium, and aluminum--lithium alloys in contact with SiC by utilizing a capillary rise apparatus. The oxide layers on the ceramic substrate and on the molten metal surface were observed to strongly influence wetting behavior. Differential optical reflectance was used to measure the optical transitions in aluminum and its alloys. Interfacial bond energies were estimated using a work of decohesion model. Punch shear tests then provided relative estimates of bond strengths for several aluminum alloys in contact with silicon carbide. Concepts from surface science and thermodynamics were coupled to theoretically predict wettability. Wetting was treated as a surface phenomenon, in which a surface reaction monolayer was sufficient to cause wetting. Aluminum matrix composite processing using the liquid metal route is complicated by the oxide barrier formed on the liquid metal. A transport model was used to explain the observed interfacial reaction behavior.

  19. Characterization of commercially pure aluminum powder for research reactor fuel plates

    SciTech Connect

    Downs, V.D. ); Wiencek, T.C. )

    1992-01-01

    Aluminum powder is used as the matrix material in the production of uranium aluminide, oxide, and silicide dispersion fuel plates for research and test reactors. variability in the characteristics of the aluminum powder, such as moisture content and particle-size distribution, influences blending and compacting of the aluminum/fuel powder. A detailed study was performed to characterize the physical properties of three aluminum powder lots. An angle-of-shear test was devised to characterize the cohesiveness of the aluminum powder. Flow-rate measurements, apparent density determination, subsieve analysis, surface area measurements, and scanning electron microscopy were also used in the study. It was found that because of the various types of commercially available powders, proper specification of powder variables will ensure the receipt of consistent raw materials. Improved control of the initial powder will reduce the variability of fuel-plate production and will improve overall plate reproducibility. It is recommended that a standard specification be written for the aluminum powder and silicide fuel.

  20. Characterization of commercially pure aluminum powder for research reactor fuel plates

    SciTech Connect

    Downs, V.D.; Wiencek, T.C.

    1992-11-01

    Aluminum powder is used as the matrix material in the production of uranium aluminide, oxide, and silicide dispersion fuel plates for research and test reactors. variability in the characteristics of the aluminum powder, such as moisture content and particle-size distribution, influences blending and compacting of the aluminum/fuel powder. A detailed study was performed to characterize the physical properties of three aluminum powder lots. An angle-of-shear test was devised to characterize the cohesiveness of the aluminum powder. Flow-rate measurements, apparent density determination, subsieve analysis, surface area measurements, and scanning electron microscopy were also used in the study. It was found that because of the various types of commercially available powders, proper specification of powder variables will ensure the receipt of consistent raw materials. Improved control of the initial powder will reduce the variability of fuel-plate production and will improve overall plate reproducibility. It is recommended that a standard specification be written for the aluminum powder and silicide fuel.

  1. Decarbonization process for carbothermically produced aluminum

    DOEpatents

    Bruno, Marshall J.; Carkin, Gerald E.; DeYoung, David H.; Dunlap, Sr., Ronald M.

    2015-06-30

    A method of recovering aluminum is provided. An alloy melt having Al.sub.4C.sub.3 and aluminum is provided. This mixture is cooled and then a sufficient amount of a finely dispersed gas is added to the alloy melt at a temperature of about 700.degree. C. to about 900.degree. C. The aluminum recovered is a decarbonized carbothermically produced aluminum where the step of adding a sufficient amount of the finely dispersed gas effects separation of the aluminum from the Al.sub.4C.sub.3 precipitates by flotation, resulting in two phases with the Al.sub.4C.sub.3 precipitates being the upper layer and the decarbonized aluminum being the lower layer. The aluminum is then recovered from the Al.sub.4C.sub.3 precipitates through decanting.

  2. Deformation analysis of boron/aluminum specimens by moire interferometry

    NASA Technical Reports Server (NTRS)

    Post, Daniel; Guo, Yifan; Czarnek, Robert

    1989-01-01

    Whole-field surface deformations were measured for two slotted tension specimens from multiply laminates, one with 0 deg fiber orientation in the surface ply and the other with 45 deg orientation. Macromechanical and micromechanical details were revealed using high-sensitivity moire interferometry. Although global deformations of all plies were essentially equal, numerous random or anomalous features were observed. Local deformations of adjacent 0 deg and 45 deg plies were very different, both near the slot and remote from it, requiring large interlaminar shear strains for continuity. Shear strains were concentrated in the aluminum matrix. For 45 deg plies, a major portion of the deformation was by shear; large plastic slip of matrix occurred at random locations in 45 deg plies, wherein groups of fibers slipped relative to other groups. Shear strains in the interior, between adjacent fibers, were larger than the measured surface strains.

  3. Fracture behavior of unidirectional boron/aluminum composite laminates

    NASA Technical Reports Server (NTRS)

    Jones, F. W.; Goree, J. G.

    1983-01-01

    An experimental investigation of the fracture behavior of unidirectional boron/aluminum composite laminates was conducted in order to verify the results of mathematical models. These models predict the fiber stresses and displacements and the amount of damage growth in a center-notched lamina as a function of the applied remote stress and the matrix and fiber material properties. A brittle lacquer coating was used to detect the yielding in the matrix while X-ray techniques were used to determine the number of broken fibers in the laminate. The notched strengths and the amounts of damage found in the specimens agreed well with those predicted by the models. It was shown that for thin laminates the amount of damage and the fiber displacements do not depend strongly on the number of plies for a given notch width.

  4. Aluminum-Based Cast In Situ Composites: A Review

    NASA Astrophysics Data System (ADS)

    Pramod, S. L.; Bakshi, Srinivasa R.; Murty, B. S.

    2015-06-01

    In situ composites are a class of composite materials in which the reinforcement is formed within the matrix by reaction during the processing. In situ method of composite synthesis has been widely followed by researchers because of several advantages over conventional stir casting such as fine particle size, clean interface, and good wettability of the reinforcement with the matrix and homogeneous distribution of the reinforcement compared to other processes. Besides this, in situ processing of composites by casting route is also economical and amenable for large scale production as compared to other methods such as powder metallurgy and spray forming. Commonly used reinforcements for Al and its alloys which can be produced in situ are Al2O3, AlN, TiB2, TiC, ZrB2, and Mg2Si. The aim of this paper is to review the current research and development in aluminum-based in situ composites by casting route.

  5. Diffusion bonded boron/aluminum spar-shell fan blade

    NASA Technical Reports Server (NTRS)

    Carlson, C. E. K.; Cutler, J. L.; Fisher, W. J.; Memmott, J. V. W.

    1980-01-01

    Design and process development tasks intended to demonstrate composite blade application in large high by-pass ratio turbofan engines are described. Studies on a 3.0 aspect radio space and shell construction fan blade indicate a potential weight savings for a first stage fan rotor of 39% when a hollow titanium spar is employed. An alternate design which featured substantial blade internal volume filled with titanium honeycomb inserts achieved a 14% potential weight savings over the B/M rotor system. This second configuration requires a smaller development effort and entails less risk to translate a design into a successful product. The feasibility of metal joining large subsonic spar and shell fan blades was demonstrated. Initial aluminum alloy screening indicates a distinct preference for AA6061 aluminum alloy for use as a joint material. The simulated airfoil pressings established the necessity of rigid air surfaces when joining materials of different compressive rigidities. The two aluminum alloy matrix choices both were successfully formed into blade shells.

  6. The Surface Tension of Pure Aluminum and Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Bainbridge, Ian Frank; Taylor, John Andrew

    2013-08-01

    The surface tension of high purity and commercial purity aluminum in vacuo was determined using the sessile drop method and the results were found to compare favorably with published data. The effects of holding atmosphere, substrate, and "surface fracture" of the sessile drop on the measured surface tension values were investigated together with the effects of different solute elements commonly present in commercial aluminum alloys. The results obtained suggest that the nature of the surface oxide film formed on the droplets (affected by alloy composition and atmosphere) and the rupture of this film are the dominant factors influencing the surface tension values obtained. Changes in surface tension values of up to 60 pct were observed. The possible effect of this variable surface tension on practical casting processes, such as direct chill casting, is suggested.

  7. Complex foamed aluminum parts as permanent cores in aluminum castings

    SciTech Connect

    Simancik, F.; Schoerghuber, F.

    1998-12-31

    The feasibility of complex shaped aluminum foam parts as permanent cores in aluminum castings has been investigated. The foamed samples were prepared by injection of the foam into sand molds. It turned out that sound castings can be produced if the foam core is properly preheated and/or surface treated before casting. The effect of the foam core on the performance of the casting was evaluated by in compression testing and by measuring structural damping. The gain in the related properties turned out to be much higher than the weight increase of the casting due to the presence of the core. The weight increase may be partially offset through a reduction of the wall-thickness of the shell.

  8. Explosive Welding of Aluminum to Aluminum: Analysis, Computations and Experiments

    NASA Astrophysics Data System (ADS)

    Grignon, F.; Benson, D.; Vecchio, K. S.; Meyers, M. A.

    2004-07-01

    6061 T0 aluminum alloy was joined to 6061 T0 aluminum alloy by explosive welding. This is a process in which the controlled energy of a detonating explosive is used to create a metallic bond between two similar or dissimilar materials. The welding conditions were tailored to produce both wavy and straight interfaces. A three-pronged study was used to establish the conditions for straight weld formation: (a) analytical calculation of the domain of weldability; (b) characterization of the explosive welding experiments carried out under different conditions, and (c) 2D finite differences simulation of these tests using the explicit Eulerian hydrocode Raven with a Johnson-Cook constitutive equation for the Al alloy. The numerical simulation and the analytical calculations confirm the experimental results and explain the difficulties met for obtaining a continuous straight interface along the entire weld.

  9. Fabrication and Structure Characterization of Alumina-Aluminum Interpenetrating Phase Composites

    NASA Astrophysics Data System (ADS)

    Dolata, Anna J.

    2016-01-01

    Alumina-Aluminum composites with interpenetrating networks structure belong to advanced materials with potentially better properties when compared with composites reinforced by particles or fibers. The paper presents the experimental results of fabrication and structure characterization of Al matrix composites locally reinforced via Al2O3 ceramic foam. The composites were obtained using centrifugal infiltration of porous ceramics by liquid aluminum alloy. Both scanning electron microscopy (SEM + EDS) and x-ray tomography were used to determine the structure of foams and composites especially in reinforced areas. The quality of castings, degree of pore filling in ceramic foams by Al alloy, and microstructure in area of interface were assessed.

  10. Three-dimensional elastoplastic stress analysis of unidirectional boron/aluminum composites

    NASA Technical Reports Server (NTRS)

    Mahishi, J. M.; Adams, D. F.

    1982-01-01

    A three dimensional elastoplastic finite element micromechanical model was developed to study the state of stress around a broken fibers in a unidirectional composite. A boron/aluminum composite consisting of 50 percent by volume of fibers in a square array and subjected to an axial loading is taken as a specific example. This loading in the fiber direction is applied in small increments, by prescribing increments of boundary displacement, until the first failure occurs. The effect of reduced material properties of the aluminum matrix material at elevated temperature is also studied. The results are presented in the form of stress contours and stress-strain plots.

  11. Microstructure and orientation effects on properties of discontinuous silicon carbide/aluminum composites

    NASA Technical Reports Server (NTRS)

    Mcdanels, D. L.; Hoffman, C. A.

    1984-01-01

    Composite panels containing up to 40 vol % discontinuous silicon carbide SiC whisker, nodule, or particulate reinforcement in several aluminum matrices are commercially fabricated and the mechanical properties and microstructual characteristics are evaluated. The yield and tensile strengths and the ductility are controlled primarily by the matrix alloy, the temper condition, and the reinforcement content. Particulate and nodule reinforcements are as effective as whisker reinforcement. Increased ductility is attributed to purer, more uniform starting materials and to more mechanical working during fabrication. Comparing mechanical properties with those of other aluminum alloys shows that these low cost, lightweight composites demonstrate very good potential for application to aerospace structures.

  12. Defect detection in aluminum laser welds using an anisotropic magnetoresistive sensor array

    SciTech Connect

    Allweins, K.; Kreutzbruck, M. von; Gierelt, G.

    2005-05-15

    For the detection of defects in aluminum laser welds an anisotropic magnetoresistive (AMR) sensor array was implemented in an eddy current testing system. The reliability of weld testing is strongly influenced by the texture of the laser weld whose field response significantly superimposes the defect's magnetic signature. A finite-element model was used to determine the influence of the weld's topology on the detection of defects such as porosities and inclusions hosted in the aluminum matrix. When using an AMR sensor array with field sensitivity of better than 1 nT/{radical}Hz defects with a radius smaller than 100 {mu}m could be detected and classified.

  13. Low-aluminum-content iron-aluminum alloys

    SciTech Connect

    Sikka, V.K.; Baldwin, R.H.; Howell, C.R.

    1993-07-01

    The low room-temperature ductility Fe{sub 3}Al-based alloys is associated with their environmental embrittlement. Reducing the aluminum level from 29 to 16 at % has been found to be an effective method in essentially eliminating the environmental-embrittlement effect and increasing the room-temperature ductility value to over 25%. This paper will present data on alloy compositions, melting, casting and processing methods, and mechanical properties. Plans for future work on these alloys will also be described.

  14. Reactively Deposited Aluminum Oxide and Fluoropolymer Filled Aluminum Oxide Protective Coatings for Polymers

    NASA Technical Reports Server (NTRS)

    Rutledge, Sharon K.; Banks, Bruce A.; Hunt, Jason

    1995-01-01

    Reactive ion beam sputter deposition of aluminum simultaneous with low energy arrival of oxygen ions at the deposition surface enables the formation of highly transparent aluminum oxide films. Thick (12 200 A), adherent, low stress, reactively deposited aluminum oxide films were found to provide some abrasion resistance to polycarbonate substrates. The reactively deposited aluminum oxide films are also slightly more hydrophobic and more transmitting in the UV than aluminum oxide deposited from an aluminum oxide target. Simultaneous reactive sputter deposition of aluminum along with polytetrafluoroethylene (PTFE Teflon) produces fluoropolymer-filled aluminum oxide films which are lower in stress, about the same in transmittance, but more wetting than reactively deposited aluminum oxide films. Deposition properties, processes and potential applications for these coatings will be discussed.

  15. Carbonate fuel cell matrix

    DOEpatents

    Farooque, M.; Yuh, C.Y.

    1996-12-03

    A carbonate fuel cell matrix is described comprising support particles and crack attenuator particles which are made platelet in shape to increase the resistance of the matrix to through cracking. Also disclosed is a matrix having porous crack attenuator particles and a matrix whose crack attenuator particles have a thermal coefficient of expansion which is significantly different from that of the support particles, and a method of making platelet-shaped crack attenuator particles. 8 figs.

  16. Carbonate fuel cell matrix

    DOEpatents

    Farooque, Mohammad; Yuh, Chao-Yi

    1996-01-01

    A carbonate fuel cell matrix comprising support particles and crack attenuator particles which are made platelet in shape to increase the resistance of the matrix to through cracking. Also disclosed is a matrix having porous crack attenuator particles and a matrix whose crack attenuator particles have a thermal coefficient of expansion which is significantly different from that of the support particles, and a method of making platelet-shaped crack attenuator particles.

  17. Microstructure and Mechanical Properties of AA1235 Aluminum Foil Stocks Produced Directly from Electrolytic Aluminum Melt

    NASA Astrophysics Data System (ADS)

    Xiong, Hanqing; Yu, Kun; Wen, Li; Yao, Sujuan; Dai, Yilong; Wang, Zhifeng

    2016-02-01

    A new process is developed to obtain high-quality AA1235 aluminum foil stocks and to replace the traditional manufacture process. During the new manufacture process, AA1235 aluminum sheets are twin-roll casted directly through electrolytic aluminum melt (EAM), and subsequently the sheets are processed into aluminum foil stocks by cold rolling and annealing. Microstructure and mechanical properties of the AA1235 aluminum sheets produced through such new process are investigated in each state by optimal microscope, scanning electron microscopy, X-ray diffraction, orientation imaging microscopy, transmission electron microscopy, etc. The results show that compared with the traditional AA1235 aluminum foil stocks produced through re-melted aluminum melt (RAM), the amount of impurities is decreased in the EAM aluminum foil stocks. The EAM aluminum foil stock obtains less β-FeSiAl5 phases, but more α-Fe2SiAl8 phases. The elongation of EAM aluminum foil stocks is improved significantly owing to more cubic orientation. Especially, the elongation value of the EAM aluminum foil stocks is approximately 25 pct higher than that of the RAM aluminum foil stocks. As a result, the EAM aluminum foil stocks are at an advantage in increasing the processing performance for the aluminum foils during subsequent processes.

  18. The effect of inversion of matrix and inclusions composition in liquation phospho-silicate glasses.

    PubMed

    Sitarz, M

    2011-08-15

    Silico-phosphate glasses of XCaPO(4)-SiO(2) and XCaPO(4)-AlPO(4)-SiO(2) (X=Na(+) and/or K(+)) system have been the subject of the presented investigations. Glasses belonging to those systems are characterized by a liquation phenomenon-spherical amorphous inclusions dispersed in an amorphous matrix. Thorough EDX investigations have shown that introduction of aluminum ions into the structure of phospho-silicate glasses results in inversion of matrix and inclusions composition, when XCaPO(4) exceeds 25-35% mol. Such a substantial influence of aluminum ions on phospho-silicate glasses texture as well as matrix and inclusions composition (inversion) must be a result of structural changes. (27)Al MAS NMR research stated that aluminum ions in structures of XCaPO(4)-AlPO(4)-SiO(2) phospho-silicate glasses always acts as a glass-forming ion-i.e. aluminum always occupies fourfold coordinated sites. (23)Na and (31)P MAS NMR research has shown that the inversion of matrix and inclusions composition, brought about by introduction of aluminum ions into the structure of phospho-silicate glasses, is an outcome of a change in phosphorous and alkaline ions coordination. PMID:20864392

  19. Cellular Magnesium Matrix Foam Composites for Mechanical Damping Applications

    NASA Astrophysics Data System (ADS)

    Shunmugasamy, Vasanth Chakravarthy; Mansoor, Bilal; Gupta, Nikhil

    2016-01-01

    The damping characteristics of metal alloys and metal matrix composites are relevant to the automotive, aerospace, and marine structures. Use of lightweight materials can help in increasing payload capacity and in decreasing fuel consumption. Lightweight composite materials possessing high damping capabilities that can be designed as structural members can greatly benefit in addressing these needs. In this context, the damping properties of lightweight metals such as aluminum and magnesium and their respective composites have been studied in the existing literature. This review focuses on analyzing the damping properties of aluminum and magnesium alloys and their cellular composites. The damping properties of various lightweight alloys and composites are compared on the basis of their density to understand the potential for weight saving in structural applications. Magnesium alloys are observed to possess better damping properties in comparison to aluminum. However, aluminum matrix syntactic foams reinforced with silicon carbide hollow particles possess a damping capacity and density comparable to magnesium alloy. By using the data presented in the study, composites with specific compositions and properties can be selected for a given application. In addition, the comparison of the results helps in identifying the areas where attention needs to be focused to address the future needs.

  20. Matrix differentiation formulas

    NASA Technical Reports Server (NTRS)

    Usikov, D. A.; Tkhabisimov, D. K.

    1983-01-01

    A compact differentiation technique (without using indexes) is developed for scalar functions that depend on complex matrix arguments which are combined by operations of complex conjugation, transposition, addition, multiplication, matrix inversion and taking the direct product. The differentiation apparatus is developed in order to simplify the solution of extremum problems of scalar functions of matrix arguments.