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1

Oxidation performance of V-Cr-Ti alloys  

SciTech Connect

Vanadium-base alloys are being considered as candidates for the first wall in advanced V-Li blanket concepts in fusion reactor systems. However, a primary deterrent to the use of these alloys at elevated temperatures is their relatively high affinity for interstitial impurities, i.e., O, N, H, and C. The authors conducted a systematic study to determine the effects of time, temperature, and oxygen partial pressure (pO{sub 2}) in the exposure environment on O uptake, scaling kinetics, and scale microstructure in V-(4--5) wt.% Cr-(4--5) wt.% Ti alloys. Oxidation experiments were conducted on the alloys at pO{sub 2} in the range of 5 x 10{sup {minus}6}-760 torr (6.6 x 10{sup {minus}4}-1 x 10{sup 5} Pa) at several temperatures in the range of 350--700 C. Models that describe the oxidation kinetics, oxide type and thickness, alloy grain size, and depth of O diffusion in the substrate of the two alloys were determined and compared. Weight change data were correlated with time by a parabolic relationship. The parabolic rate constant was calculated for various exposure conditions and the temperature dependence of the constant was described by an Arrhenius relationship. The results showed that the activation energy for the oxidation process is fairly constant at pO{sub 2} levels in the range of 5 x 10{sup {minus}6}-0.1 torr. The activation energy calculated from data obtained in the air tests was significantly lower, whereas that obtained in pure-O tests (at 760 torr) was substantially higher than the energy obtained under low-pO{sub 2} conditions. The oxide VO{sub 2} was the predominant phase that formed in both alloys when exposed to pO{sub 2} levels of 6.6 x 10{sup {minus}4} to 0.1 torr. V{sub 2}O{sub 5} was the primary phase in specimens exposed to air and to pure O{sub 2} at 760 torr. The implications of the increased O concentration are increased strength and decreased ductility of the alloy. However, the strength of the alloy was not a strong function of the O concentration of the alloy, but an increase in O concentration did cause a substantial decrease in ductility.

Natesan, K.; Uz, M.

2000-04-03

2

Impurity effects on gas tungsten arc welds in V–Cr–Ti alloys  

Microsoft Academic Search

Plates 6.4 mm thick of V–Cr–Ti alloys, mostly V–4Cr–4Ti, were welded in a glove box argon atmosphere. A hot titanium getter led to excessive hydrogen concentrations. A cold zirconium–aluminum getter was used to reduce both oxygen and hydrogen. It was observed that a major source of hydrogen was dissociation of water vapor by the electric arc of the welding torch.

M. L Grossbeck; J. F King; D. T Hoelzer

2000-01-01

3

Development of techniques for welding V–Cr–Ti alloys  

Microsoft Academic Search

Welding vanadium alloys is complicated by interstitial impurity introduction and redistribution at elevated temperatures. Gas tungsten arc (GTA) welding, which will probably be required for the fabrication of large tokamak structures, must be done in a glove box environment. Welds were evaluated by Charpy testing. GTA welds could be made with a ductile to brittle transition temperature (DBTT) of 50°C

M. L. Grossbeck; J. F. King; D. J. Alexander; P. M. Rice; G. M. Goodwin

1998-01-01

4

Performance of V-Cr-Ti alloys in a hydrogen environment  

SciTech Connect

A systematic study is underway at Argonne National Laboratory to evaluate the mechanical properties of several V-Cr-Ti alloys after exposure to environments containing hydrogen at various partial pressures. The goal is to correlate the chemistry of the exposure environment with hydrogen uptake by the samples and with the resulting influence on microstructures and tensile properties of the alloys. Other variables examined are specimen cooling rate and synergistic effects, if any, of oxygen and hydrogen on tensile behavior of the alloys. Experiments were conducted to evaluate the effect of pH{sub 2} in the range of 3 x 10{sup {minus}6} and 1 torr on tensile properties of two V-Cr-Ti alloys. Up to pH{sub 2} of 0.05 torr, negligible effect of H was observed on either maximum engineering stress or uniform and total elongation. However, uniform and total elongation decreased substantially when the alloys were exposed at 500 C to 1.0 torr of H{sub 2} pressure. Preliminary data from sequential exposures of the materials to low-pO{sub 2} and several low-pH{sub 2} environments did not reveal adverse effects on the maximum engineering stress or on uniform and total elongation when the alloy contained {approx} 2,000 wppm O and 16 wppm H. Furthermore, tests in H{sub 2}-exposed specimens, initially annealed at various temperatures, showed that grain-size variation by a factor of {approx} 2 had little or no effect on tensile properties. Also, specimen cooling rate had a small effect, if any, on the tensile properties of the alloy.

Natesan, K.; Soppet, W. K.

2000-04-03

5

Feasibility of correlating V-Cr-Ti alloy weld strength with weld chemistry. CRADA final report  

SciTech Connect

The mechanical properties of refractory metals such as vanadium are determined to a large extent by the interstitial impurities in the alloy. In the case of welding, interstitial impurities are introduced in the welding process from the atmosphere and by dissolution of existing precipitates in the alloy itself. Because of the necessity of having an ultra-pure atmosphere, a vacuum chamber or a glove box is necessary. In the V-Cr-Ti system, the titanium serves as a getter to control the concentration of oxygen and nitrogen in solid solution in the alloy. In this project the secondary ion mass spectrometry (SIMS) technique was used to detect, measure, and map the spacial distribution of impurity elements in welds in the alloy V-4Cr-4Ti. An attempt was then made to correlate the concentrations and distributions of the impurities with mechanical properties of the welds. Mechanical integrity of the welds was determined by Charpy V-notch testing. Welds were prepared by the gas-tungsten-arc (GTA) method. Charpy testing established a correlation between weld impurity concentration and the ductile to brittle transition temperature (DBTT). Higher concentrations of oxygen resulted in a higher DBTT. An exception was noted in the case of a low-oxygen weld which had a high hydrogen concentration resulting in a brittle weld. The concentrations and distributions of the impurities determined by SIMS could not be correlated with the mechanical properties of the welds. This research supports efforts to develop fusion reactor first wall and blanket structural materials.

Grossbeck, M.L. [Oak Ridge National Lab., TN (United States); Odom, R.W. [Charles Evans and Associates, Redwood City, CA (United States)

1998-06-01

6

Feasibility of correlating V-Cr-Ti alloy weld strength with weld chemistry. CRADA final report  

Microsoft Academic Search

The mechanical properties of refractory metals such as vanadium are determined to a large extent by the interstitial impurities in the alloy. In the case of welding, interstitial impurities are introduced in the welding process from the atmosphere and by dissolution of existing precipitates in the alloy itself. Because of the necessity of having an ultra-pure atmosphere, a vacuum chamber

M. L. Grossbeck; R. W. Odom

1998-01-01

7

CaO insulator coatings and self-healing of defects on V-Cr-Ti alloys in liquid lithium  

SciTech Connect

Electrically insulating and corrosion-resistant coatings are required at the liquid metal/structural interface in fusion first-wall/blanket applications. The electrical resistance of CaO coatings produced on V-5%Cr-5%Ti by exposure of the alloy to liquid Li that contained 0.5--85 wt.% dissolved Ca was measured as a function of time at temperatures between 250 and 600{degrees}C. The solute element, Ca in liquid Li, reacted with the alloy substrate at 400--420{degrees}C to produce a CaO coating. Resistance of the coating layer measured in-situ in liquid Li was {approx}10{sup 6} {Omega} at 400{degrees}C. Thermal cycling between 300 and 700{degrees}C changed the coating layer resistance. which followed insulator behavior. These results suggest that thin homogeneous coatings can be produced on variously shaped surfaces by controlling the exposure time, temperature, and composition of the liquid metal. The technique can be applied to various shapes(e.g., inside/outside of tubes, complex geometrical shapes) because the coating is formed by liquid-phase reaction. Examination of the specimens after cooling to room temperature revealed no spallation, but homogeneous crazing cracks were present in the CaO coating. Additional tests to investigate the in-situ self-healing behavior of the cracks indicated that rapid healing occurred at {ge}360{degrees}C.

Park, J.H.; Kassner, T.F.

1996-02-01

8

CaO insulator coatings and self-healing of defects on V-Cr-Ti alloys in liquid lithium system  

SciTech Connect

Electrically insulating and corrosion-resistant coatings are required at the liquid metal/structural interface in fusion first-wall/blanket applications. Electrical resistance of CaO coatings that were produced on V-5%Cr-5%Ti by exposure of the alloy to liquid Li containing 0.5-85 wt.% dissolved Ca was measured as a function of time at temperatures between 250 and 600{degrees}C. The solute element, Ca in liquid Li, reacted with the alloy substrate at 400-420{degrees}C to produce a CaO coating. Resistance of the coating layer measured in-situ in liquid Li was {approx}10{sup 6} {Omega} at 400{degrees}C. Thermal cycling between 300 and 700{degrees}C changed the coating layer resistance, which followed insulator behavior. These results suggest that thin homogeneous coatings can be produced on variously shaped surfaces by controlling the exposure time, temperature, and composition of the liquid metal. The technique can be applied to various shapes (e.g., inside/outside of tubes, complex geometrical shapes) because the coating is formed by liquid-phase reaction. Examination of the specimens after cooling to room temperature revealed no spallation, but homogeneous crazing cracks were present in the CaO coating. Additional tests to investigate the in-situ self-healing behavior of the cracks indicated that rapid healing occurred at {>=}360{degrees}C.

Park, J.H.; Kassner, T.F.

1995-09-01

9

Effects of substitutions M on the formation, structure and magnetic properties of Sm 2Fe 15M 2C 2 (M = V, Cr, Ti, Nb, Zr, Mn and Mo) compounds  

Microsoft Academic Search

The effects of substitutions M on the formation, structure and magnetic properties of Sm2Fe15M2C2 (M = V, Cr, Ti, Nb, Zr, Mn and Mo) compounds have been systematically studied using XRD, magnetic and Mössbauer measurements. It has been found that V, Cr, Ti, Nb and Zr can help to form the 2 : 17 carbides, with a certain amount of

Zhongmin Chen; G. C. Hadjipanayis; M. Daniel; M. Digas; A. Moukarika; V. Papaefthymiou

1998-01-01

10

Effects of substitutions M on the formation, structure and magnetic properties of Sm2Fe15M2C2 (M = V, Cr, Ti, Nb, Zr, Mn and Mo) compounds  

Microsoft Academic Search

The effects of substitutions M on the formation, structure and magnetic properties of Sm2Fe15M2C2 (M = V, Cr, Ti, Nb, Zr, Mn and Mo) compounds have been systematically studied using XRD, magnetic and Mössbauer measurements. It has been found that V, Cr, Ti, Nb and Zr can help to form the 2 : 17 carbides, with a certain amount of

M. Daniel; M. Digas; A. Moukarika; V. Papaefthymiou; Z. Chen; G. C. Hadjipanayis

1998-01-01

11

Effects of substitutions M on the formation, structure and magnetic properties of Sm2Fe15M2C2 (M = V, Cr, Ti, Nb, Zr, Mn and Mo) compounds  

NASA Astrophysics Data System (ADS)

The effects of substitutions M on the formation, structure and magnetic properties of Sm2Fe15M2C2 (M = V, Cr, Ti, Nb, Zr, Mn and Mo) compounds have been systematically studied using XRD, magnetic and Mössbauer measurements. It has been found that V, Cr, Ti, Nb and Zr can help to form the 2 : 17 carbides, with a certain amount of MC (TiC, NbC or ZrC) carbides present in the Ti, Nb or Zr substituted samples, whereas Mn and Mo cannot help to form the 2: 17 carbides. Magnetic measurements reveal that Cr and Nb substituted carbides have a strong c-axis magnetocrystalline anisotropy with anisotropy fields of 93.5 kOe for M = Cr and 72.5 kOe for M = Nb. Mössbauer studies reveal that Cr occupies mainly the 6c and 18h sites whereas Nb occupies only the 18f site.

Daniel, M.; Digas, M.; Moukarika, A.; Papaefthymiou, V.; Chen, Z.; Hadjipanayis, G. C.

1998-01-01

12

Correlation of microstructure and tensile and swelling behavior of neutron-irradiated vanadium alloys  

NASA Astrophysics Data System (ADS)

The microstructures of V?Ti?, V?Cr?Ti, and V?Ti?Si alloys were characterized by transmission electron microscopy after neutron irradiation in the Fast Flux Test Facility (FFTF) at 420 and 600°C up to 114 dpa. Two types of irradiation-induced precipitates were identified, i.e., Ti2O and Ti5(Si,P)3. Thermal precipitates of Ti(O,N,C) were also observed in all unirradiated and irradiated specimens. Copious precipitation of the Ti5(Si,P)3 phase was associated with superior resistance to void swelling. In specimens with significant swelling, Ti5(Si,P)3 precipitation was negligible. Ductility is significantly reduced when the precipitation of Ti2O and Ti5(Si,P)3 is pronounced. These observations indicate that initial composition, fabrication processes, and irradiation-induced precipitation are interrelated and are important factors to consider in developing an optimized alloy.

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

1992-09-01

13

Correlation of microstructure and tensile and swelling behavior of neutron-irradiated vanadium alloys  

SciTech Connect

The microstructures of V-Ti, V-Cr-Ti, and V-Ti-Si alloys were characterized by transmission electron microscopy (TEM) after neutron irradiation in the Fast Flux Test Facility (FFTF) at 420 and 600{degrees}C to influences up to 114 dpa. Two types of irradiation-induced precipitates were identified, i.e., Ti{sub 2}O and Ti{sub 5}(Si,P){sub 3}. Blocky Ti(O,N,C) precipitates, which form by thermal processes during ingot fabrication, also were observed in all unirradiated and irradiated specimens. Irradiation-induced precipitation of spherical (<15 nm in diameter) Ti{sub 5}(Si,P){sub 3} phase was associated with superior resistance to void swelling. In specimens with negligible swelling, Ti{sub 5}(Si,P){sub 3} precipitation was significant. It seems that ductility is significantly reduced when the precipitation of Ti{sub 2}O and Ti{sub 5}(Si,P){sub 3} is pronounced. These observations indicate that initial composition; fabrication processes; actual solute compositions of Ti, O, N, C, P, and Si after fabrication; O, N, and C uptake during service; and irradiation-induced precipitation ae interrelated and are important factors to consider in developing an optimized alloy. 15 refs., 8 figs.

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

1991-10-01

14

[Fatigue properties of dental alloys. 12% Au-Pd-Ag alloy and type III gold alloy].  

PubMed

Usually the mechanical properties of dental alloys are determined from the values obtained through static tests of their tensile strength, hardness, etc. Generally, high tensile strength and ductility are preferred. However, when small stresses within proportional limits are applied repeatedly (even though not amounting to destructive forces in static tests), they may cause rupture in the alloy or, at least, cause it to lose its original mechanical properties. This phenomenon is called metal fatigue. It is estimated that the intraoral stress loads received by dental restorations during mastication or during insertion and removal of appliances are repeated more than 3 x 10(5) times/year. From this standpoint, it may be more appropriate to estimate the fracture strength of such dental alloys based on the fatigue properties of the restorative materials used for clasps, bars, and fixed bridges. For this reason, it is necessary to obtain data through fatigue tests on the fatigue strength and the fatigue endurance limits of dental alloys, and it is important to find a correlation between these data and the static data on tensile strengths and ductility obtained by tensile tests. Two alloys are used in these experiments. Both wrought specimens and cast specimens of 12% Au-Pd-Ag and Type III gold alloy were prepared for the fatigue tests. The size of the rectangular wrought specimens was 3 x 4 x 110 mm. The 12% Au-Pd-Ag alloy was heated to 800 degrees C for 15 minutes, quenched, and reheated to 400 degrees C for 20 minutes and quenched again according to the manufacturer's instructions for heat treatment. The Type III gold alloy was heated to 700 degrees C for 10 minutes, quenched, and reheated to 350 degrees C for 20 minutes and quenched again. The cylindrical cast specimens were 60 mm long and 2 mm in diameter. They were invested by conventional methods and cast in a centrifugal casting machine, Thermotrol Model 2500. The four point bending test for the wrought specimen was performed with a Universal Fatigue testing machine, Shimazu UF-15 at a stress amplitude rate of 30 Hz. The cylindrical cast specimens were tested in cyclic tension in a Hydraulic IC Servo Machine, Instron Model 8501 at a gauge length of 25 mm and a stress amplitude of 10 Hz. The tensile tests for both wrought and cast specimens were performed with a Universal Testing Machine, Instron Model 1125 and measured at a cross-head speed of 1 mm/min.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2489466

Kato, H

1989-12-01

15

Electronic Structure of CsCl-Type Transition Metal Alloys  

Microsoft Academic Search

Transition metal alloys have a tendency to make a stable ordered lattice of the CsCl-type, when the average number of conduction electrons (including d-electrons) is the same as that of Cr. The electronic structures of VMn, TiFe and ScCo are investigated by the self-consistent KKR method, to clarify the stability of these alloys. It is found that the density-of-states of

Jiro Yamashita; Setsuro Asano

1972-01-01

16

Superelastic behavior of a ?-type titanium alloy.  

PubMed

The superelasticity of a ? Ti alloy, Ti-7.5Nb-4Mo-2Sn (in atom percent) was evaluated by using loading and unloading cyclic tensile tests under different thermomechanical conditions, and the effects of the plastic deformation, temperature, strain rate and cyclic loading on the superelasticity of the alloy were studied. It is found that, with the applied strain increasing, the stress inducing the reverse martensitic transformation ???-? and the strain recovery rate ? decreases. The increase of deformation temperature promotes ??-??, ???-? and ??, and the temperature dependency of the stresses obeys the Clausius-Clapeyron relation. ??-??, ???-? and ?? are independent on the strain rate when it is lower than 8.35×10(-4)s(-1). However, when the strain rate is higher than 8.35×10(-4)s(-1), ??-?? and ?? increase, but ???-? decreased with increasing the strain rate. By cyclic loading and unloading to the maximum strain of 6% at 25°C under the strain rate of 1.67×10(-4)s(-1), the alloy exhibits a improved superelasticity after seventh cycles due to the training effect. PMID:23455161

Zhang, D C; Mao, Y F; Yan, M; Li, J J; Su, E L; Li, Y L; Tan, S W; Lin, J G

2013-02-01

17

Aluminum Alloying Effects on Lattice Types, Microstructures, and Mechanical Behavior of High-Entropy Alloys Systems  

NASA Astrophysics Data System (ADS)

The crystal lattice type is one of the dominant factors for controlling the mechanical behavior of high-entropy alloys (HEAs). For example, the yield strength at room temperature varies from 300 MPa for the face-centered-cubic (fcc) structured alloys, such as the CoCrCuFeNiTi x system, to about 3,000 MPa for the body-centered-cubic (bcc) structured alloys, such as the AlCoCrFeNiTi x system. The values of Vickers hardness range from 100 to 900, depending on lattice types and microstructures. As in conventional alloys with one or two principal elements, the addition of minor alloying elements to HEAs can further alter their mechanical properties, such as strength, plasticity, hardness, etc. Excessive alloying may even result in the change of lattice types of HEAs. In this report, we first review alloying effects on lattice types and properties of HEAs in five Al-containing HEA systems: Al x CoCrCuFeNi, Al x CoCrFeNi, Al x CrFe1.5MnNi0.5, Al x CoCrFeNiTi, and Al x CrCuFeNi2. It is found that Al acts as a strong bcc stabilizer, and its addition enhances the strength of the alloy at the cost of reduced ductility. The origins of such effects are then qualitatively discussed from the viewpoints of lattice-strain energies and electronic bonds. Quantification of the interaction between Al and 3d transition metals in fcc, bcc, and intermetallic compounds is illustrated in the thermodynamic modeling using the CALculation of PHAse Diagram method.

Tang, Zhi; Gao, Michael C.; Diao, Haoyan; Yang, Tengfei; Liu, Junpeng; Zuo, Tingting; Zhang, Yong; Lu, Zhaoping; Cheng, Yongqiang; Zhang, Yanwen; Dahmen, Karin A.; Liaw, Peter K.; Egami, Takeshi

2013-10-01

18

Tube type micro manipulator using shape memory alloy (SMA)  

Microsoft Academic Search

A five degrees of freedom tube type micro manipulator has been successfully developed. The manipulator is 1 mm in diameter and 80 mm in length. The SMA (shape memory alloy) plate is applied as an actuator. For integration of electrical components of this manipulator, MIF (multifunction integrated film) has been developed. The MIF is flexible film, which includes heaters, sensors,

Shinji Aramaki; Shinji Kaneko; Kazuhiko Arai; Yuichiro Takahashi; Hideyuki Adachi; Kazuhisa Yanagisawa

1995-01-01

19

Development and testing ov danadium alloys for fusion applications  

SciTech Connect

V base alloys have advantages for fusion reactor first-wall and blanket structure. To screen candidate alloys and optimize a V-base alloy, physical and mechanical properties of V-Ti, V-Cr-Ti, and V-Ti- Si alloys were studied before and after irradiation in Li environment in fast fission reactors. V-4Cr-4Ti containing 500-1000 wppM Si and <1000 wppM O+N+C was investigated as the most promising alloy, and more testing is being done. Major results of the work are presented in this paper. The reference V-4Cr-4Ti had the most attractive combination of the mechanical and physical properties that are prerequisite for first-wall and blanket structures: good thermal creep, good tensile strength/ductility, high impact energy, excellent resistance to swelling, and very low ductile-brittle transition temperature before and after irradiation. The alloy was highly resistant to irradiation-induced embrittlement in Li at 420-600 C, and the effects of dynamically charged He on swelling and mechanical properties were insignificant. However, several important issues remain unresolved: welding, low-temperature irradiation, He effect at high dose and high He concentration, irradiation creep, and irradiation performance in air or He. Initial results of investigation of some of these issues are also given.

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

1996-10-01

20

Sensitization and corrosion of alloy 315 SN vs type 321 stainless steel  

SciTech Connect

ASTM A 262, Practice E, tests were performed to study the sensitization time-temperature and corrosion resistance of stainless steel (SS) alloy 315 SN used in automotive exhaust systems. A comparison was made to type 321 SS. Alloy 315 SN was sensitized and severely attacked by intergranular corrosion, through type 321 was not.

Carpenter, J.E.; Cochran, F.L.; Corbett, P.M. (Flexonics Inc., Bartlett, IL (United States). Materials Research Lab.)

1993-10-01

21

Electrochemical behavior of Alloy 22 and friction type rock bolt  

Microsoft Academic Search

Alloy 22 (Ni-22Cr-13Mo-3Fe-3W) is a candidate alloy for the outer shell of spent nuclear materials storage containers in the Yucca Mountain High Level Nuclear Waste Repository because of its excellent corrosion resistance. The nuclear waste container is cylindrical in shape and the end caps are welded. Typically, Alloy 22 retains the high temperature single phase cubic structure near room temperature,

2006-01-01

22

Microstructure and phase identification in type 304 stainless steel-zirconium alloys  

SciTech Connect

Stainless steel-zirconium alloys have been developed at Argonne National Laboratory to contain radioactive metal isotopes isolated from spent nuclear fuel. This article discusses the various phases that are formed in as-cast alloys of type 304 stainless steel and zirconium that contain up to 92 wt pct Zr. Microstructural characterization was performed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), and crystal structure information was obtained by X-ray diffraction. Type 304SS-Zr alloys with 5 and 10 wt pct Zr have a three-phase microstructure--austenite, ferrite, and the Laves intermetallic, Zr(Fe,Cr,Ni){sub 2+x}, whereas alloys with 15, 20, and 30 wt pct Zr contain only two phases--ferrite and Zr(Fe,Cr,Ni){sub 2+x}. Alloys with 45 to 67 wt pct Zr contain a mixture of Zr(Fe,Cr,Ni){sub 2+x} and Zr{sub 2}(Ni,Fe), whereas alloys with 83 and 92 wt pct Zr contain three phases--{alpha}-Zr, Zr{sub 2}(Ni,Fe), and Zr(Fe,Cr,Ni){sub 2+x}. Fe{sub 3}Zr-type and Zr{sub 3}Fe-type phases were not observed in the type 304SS-Zr alloys. The changes in alloy microstructure with zirconium content have been correlated to the Fe-Zr binary phase diagram.

Abraham, D.P.; McDeavitt, S.M.; Park, J. [Argonne National Lab., IL (United States)

1996-08-01

23

The influences of microstructure and nitrogen alloying on pitting corrosion of type 316L and 20 wt.% Mn-substituted type 316L stainless steels  

Microsoft Academic Search

The effects of nitrogen alloying on pitting corrosion of type 316LN and 20 wt.% Mn-substituted type 316LN stainless steels were investigated by potentiodynamic polarization tests in Cl? ion-bearing neutral and acidic solutions. Pitting resistance was markedly improved through the nitrogen alloying in both types of alloys, compared with the nitrogen-free alloys. It was confirmed that the added nitrogen was solid-solutioned

Yun Soo Lim; Joung Soo Kim; Se Jin Ahn; Hyuk Sang Kwon; Yasuyuki Katada

2001-01-01

24

Beta type Ti-Mo alloys with changeable Young's modulus for spinal fixation applications.  

PubMed

To develop a novel biomedical titanium alloy with a changeable Young's modulus via deformation-induced ? phase transformation for the spinal rods in spinal fixation devices, a series of metastable ? type binary Ti-(15-18)Mo alloys were prepared. In this study, the microstructures, Young's moduli and tensile properties of the alloys were systemically examined to investigate the effects of deformation-induced ? phase transformation on their mechanical properties. The springback of the optimal alloy was also examined. Ti-(15-18)Mo alloys subjected to solution treatment comprise a ? phase and a small amount of athermal ? phase, and they have low Young's moduli. All the alloys investigated in this study show an increase in the Young's modulus owing to deformation-induced ? phase transformation during cold rolling. The deformation-induced ? phase transformation is accompanied with {332}(?) mechanical twinning. This resulted in the maintenance of acceptable ductility with relatively high strength. Among the examined alloys, the Ti-17Mo alloy shows the lowest Young's modulus and the largest increase in the Young's modulus. This alloy exhibits small springback and could be easily bent to the required shape during operation. Thus, Ti-17Mo alloy is considered to be a potential candidate for the spinal rods in spinal fixation devices. PMID:22326686

Zhao, Xingfeng; Niinomi, Mitsuo; Nakai, Masaaki; Hieda, Junko

2012-02-09

25

Extruded Bismuth-Telluride-Based n Type Alloys for Waste Heat Thermoelectric Recovery Applications  

Microsoft Academic Search

Thermoelectric (TE) generator modules for a number of waste heat recovery applications are required to operate between room\\u000a temperature and 500 K, a temperature range for which the composition of bismuth-telluride-based alloys needs to be adjusted\\u000a to optimize performance. In particular n-type alloys do not perform as well as p-type and require a more systematic study. We have produced, by mechanical

C. André; D. Vasilevskiy; S. Turenne; R. A. Masut

2009-01-01

26

Microstructure of fine-grained ?-type titanium alloy produced by mechanical alloying and consolidation process  

Microsoft Academic Search

The mechanical alloying (MA) treatment was applied to the mixed powder of titanium and iron with average composition of Ti–15mass%Fe. Heptane was also used for the MA treatment as a source of carbon. The MA treatment resulted in the production of alloyed powder in which all constituents were fully dissolved in the solid solution. By the consolidation of the MA-treated

T. Tsuchiyama; S. Hamamoto; K. Nakashima; S. Takaki

2008-01-01

27

Grain size control and superplasticity in 6013-type aluminum alloys  

NASA Astrophysics Data System (ADS)

Aluminum alloys have been the material of choice for aircraft construction since the 1930's. Currently, the automotive industry is also showing an increasing interest in aluminum alloys as structural materials. 6xxx aluminum alloys possess a combination of strength and formability which makes them attractive to both industries. In addition, 6xxx alloys are highly weldable, corrosion resistant, and low in cost as compared with the 2xxx and 7xxx aluminum alloys. Superplastic forming (SPF) is a manufacturing process which exploits the phenomenon of superplasticity in which gas pressure is used to form complex-shaped parts in a single forming operation. This reduces part counts and the need for fasteners and connectors, resulting in reduced product weight. Reduced product/vehicle weight improves fuel economy. Most alloys must be specially processed for superplasticity. Much research effort has been directed at the development of thermomechanical processes for the grain refinement of aluminum alloys by static or dynamic recrystallization. to induce superplasticity. While large numbers of studies have been conducted on 2xxx, 5xxx, 7xxx, and 8xxx aluminum alloys, very few studies have been focused on the grain refinement of 6xxx aluminum alloys for superplasticity. The current research describes a new thermomechanical process for application to 6xxx aluminum alloys for grain refinement and superplasticity. The process is shown to successfully refine and induce superplasticity in an Al-Mg-Si-Cu alloy which falls within the compositional limits of both 6013 and 6111. The grain refinement is by particle-stimulated nucleation of recrystallization. The microstructural evolution during the thermomechanical processing is characterized in terms of precipitate size, shape, distribution and composition; texture; recrystallization; and grain size, shape, and thermal stability. The new process produces a statically-stable, weakly-textured, equiaxed grain structure with an average grain diameter of ˜10 mum. The refined microstructure exhibits superplasticity above 500°C, where the strain rate sensitivity reaches a maximum of 0.5 (at 540°C for strain rates between 2 x 10-4 s-1 and 5 x 10-4 s-1). The maximum uniaxial elongation (375%) occurred in the regime of the maximum strain rate sensitivity. The corresponding flow stress was 680 psi (4.7 Mpa). Biaxial cone tests were performed in order to better evaluate the high-temperature forming characteristics of the material. During tests with back pressure, cone height-to-radius ratios near 1.2 were obtained with maximum strain approaching 2.0 for strain rates near 1 x 10-3 s-1 . The effect of superplastic deformation on the microstructure is described in terms of the effect of strain on grain size and porosity for a cone sample. The ultimate goal of the project is to advance the fundamental understanding of the complex interrelationships between processing, microstructure, and superplastic performance.

Troeger, Lillianne Plaster Whitelock

28

Uniaxial creep behavior of V-4Cr-4Ti alloy.  

SciTech Connect

We are undertaking a systematic study at Argonne National Laboratory to evaluate the uniaxial creep behavior of V-Cr-Ti alloys in a vacuum environment as a function of temperature in the range of 650-800 C and at applied stress levels of 75-380 MPa. Creep strain in the specimens is measured by a linear-variable-differential transducer, which is attached between the fixed and movable pull rods of the creep assembly. Strain is measured at sufficiently frequent intervals during testing to define the creep strain/time curve. A linear least-squares analysis function is used to ensure consistent extraction of minimum creep rate, onset of tertiary creep, and creep strain at the onset of tertiary creep. Creep test data, obtained at 650, 700, 725, and 800 C, showed power-law creep behavior. Extensive analysis of the tested specimens is conducted to establish hardness profiles, oxygen content, and microstructural characteristics. The data are also quantified by the Larson-Miller approach, and correlations are developed to relate time to rupture, onset of tertiary creep, times for 1 and 2% strain, exposure temperature, and applied stress.

Natesan, K.; Soppet, W.K.; Purohit, A.

2002-04-15

29

Magnetic transformation of Ni 2 AlMn heusler-type shape memory alloys  

Microsoft Academic Search

It has recently been reported that the movement of twin (or variant) boundaries, induced by a magnetic field during the martensitic transformation, affects the magnetic properties and shape change in the ferromagnetic NiGaMn shape memory (SM) alloys. These observations suggest that the NiGaMn SM alloys with an L2⁠(NiâGaMn: Heusler) structure have the potential for use as a new type

F. Gejima; Y. Sutou; R. Kainuma; K. Ishida

1999-01-01

30

The effect of Mg on the structure and properties of Type 319 aluminum casting alloys  

Microsoft Academic Search

The precipitation hardening behavior of a Type 319 aluminum alloy (Al–6.7wt.% Si–3.75wt.% Cu) with and without 0.45wt.% Mg has been investigated. It is shown that both ? and Q phase exist in the as-cast samples and are dissolved during solution heat treatment. Subsequent artificial aging results in the precipitation of both the metastable ?? phase typical of aged alloy 319

J. Y. Hwang; R. Banerjee; H. W. Doty; M. J. Kaufman

2009-01-01

31

Nanocrystalline titanium-type metal hydride electrodes prepared by mechanical alloying  

Microsoft Academic Search

Mechanical alloying (MA) was employed to produce nanocrystalline TiFe1?xNix alloys (x=0, 0.25, 0.5, 0.75 and 1.0). XRD analysis showed that, after 25 h of milling, the starting mixture of the elements had decomposed into an amorphous phase. Following annealing in high purity argon at 750°C for 0.5 h, XRD confirmed the formation of the CsCl-type structures with crystallite sizes of

M Jurczyk; E Jankowska; M Nowak; J Jakubowicz

2002-01-01

32

Spark plasma sintering synthesis of porous nanocrystalline titanium alloys for biomedical applications.  

PubMed

The reason for the extended use of titanium and its alloys as implant biomaterials stems from their lower elastic modulus, their superior biocompatibility and improved corrosion resistance compared to the more conventional stainless steel and cobalt-based alloys [Niinomi, M., Hattori, T., Niwa, S., 2004. Material characteristics and biocompatibility of low rigidity titanium alloys for biomedical applications. In: Jaszemski, M.J., Trantolo, D.J., Lewandrowski, K.U., Hasirci, V., Altobelli, D.E., Wise, D.L. (Eds.), Biomaterials in Orthopedics. Marcel Dekker Inc., New York, pp. 41-62]. Nanostructured titanium-based biomaterials with tailored porosity are important for cell-adhesion, viability, differentiation and growth. Newer technologies like foaming or low-density core processing were recently used for the surface modification of titanium alloy implant bodies to stimulate bone in-growth and improve osseointegration and cell-adhesion, which in turn play a key role in the acceptance of the implants. We here report preliminary results concerning the synthesis of mesoporous titanium alloy bodies by spark plasma sintering. Nanocrystalline cp Ti, Ti-6Al-4V, Ti-Al-V-Cr and Ti-Mn-V-Cr-Al alloy powders were prepared by high-energy wet-milling and sintered to either full-density (cp Ti, Ti-Al-V) or uniform porous (Ti-Al-V-Cr, Ti-Mn-V-Cr-Al) bulk specimens by field-assisted spark plasma sintering (FAST/SPS). Cellular interactions with the porous titanium alloy surfaces were tested with osteoblast-like human MG-63 cells. Cell morphology was investigated by scanning electron microscopy (SEM). The SEM analysis results were correlated with the alloy chemistry and the topographic features of the surface, namely porosity and roughness. PMID:17869173

Nicula, R; Lüthen, F; Stir, M; Nebe, B; Burkel, E

2007-08-07

33

Investigation on the primary creep of a nickel based alloy. [Nimonic 75 type alloy  

SciTech Connect

It is widely accepted that dislocation climb is involved in the steady state (i.e. secondary) creep at high temperatures, which is characterized by the formation and evolution of substructures. In current theories of steady state creep, dislocation climb is regarded as the rate controlling process. However, the role of dislocation climb in the primary (i.e. transient) creep at high temperatures is not clear. The present paper is to report the observations by transmission electron microscopy (TEM) on high temperature creep of a nickel based alloy. It will be shown that dislocation climb plays an important role not only in the steady state creep, but also in the primary creep.

Kong, Q.P.; Wang, X. (Inst. of Solid State Physics, Hefei (China))

1993-07-01

34

Corrosion potential measurements on type 304 SS and alloy 182 in simulated BWR environments  

SciTech Connect

The effects of dissolved oxygen, hydrogen, and hydrogen peroxide on the corrosion (electrochemical) potentials (ECPs) of type 304 SS and alloy 182 in simulated boiling water reactor (BWR) coolant environments under various water chemistry conditions at 288 C are reported. In oxygenated systems, the measured ECP fell within the range +20 to [minus]600 mV (vs SHE) depending on the O[sub 2] concentration. The effect of water flow rate on the ECP was also studied as function of dissolved O[sub 2] concentration. Increasing flow rate at constant oxygen concentration increased the ECPs of type 304 SS and alloy 182. The effect of hydrogen peroxide (H[sub 2]O[sub 2]) on the ECP of type 304 SS and alloy 182 in pure water was also determined. The authors found that the concentration of oxygen and the ECP increased immediately when H[sub 2]O[sub 2] was injected into the cell. The measured corrosion potentials of both alloys were 200 to 400 mV more positive than for dissolved O[sub 2] at similar levels. However, the ECP was lower than that expected theoretically from a mixed potential model (COREPOTENTIAL), which the authors attribute to thermal decomposition of H[sub 2]O[sub 2]. The ECPs of type 304 SS and alloy 182 in water containing various O[sub 2]/H[sub 2]/H[sub 2]O[sub 2] combinations were measured and compared with theoretical data from COREPOTENTIAL. The ECPs were lower than expected due to decomposition of H[sub 2]O[sub 2] in the high-temperature environment. Finally, the difference between the ECP of type 304 SS and alloy 182 was negligible (normally < [plus minus] 20 mV) under all conditions.

Macdonald, D.D. (Pennsylvania State Univ., University Park (United States)); Song, H. (SRI International, Menlo Park, CA (United States)); Makela, K. (VTT, Espoo (Finland)); Yoshida, K. (Ishikawajima-Harima Heavy Industries Co., Ltd., Yokohama (Japan))

1993-01-01

35

Enhanced thermoelectric figure-of-merit in nanostructured p-type silicon germanium bulk alloys.  

PubMed

A dimensionless thermoelectric figure-of-merit (ZT) of 0.95 in p-type nanostructured bulk silicon germanium (SiGe) alloys is achieved, which is about 90% higher than what is currently used in space flight missions, and 50% higher than the reported record in p-type SiGe alloys. These nanostructured bulk materials were made by using a direct current-induced hot press of mechanically alloyed nanopowders that were initially synthesized by ball milling of commercial grade Si and Ge chunks with boron powder. The enhancement of ZT is due to a large reduction of thermal conductivity caused by the increased phonon scattering at the grain boundaries of the nanostructures combined with an increased power factor at high temperatures. PMID:19367858

Joshi, Giri; Lee, Hohyun; Lan, Yucheng; Wang, Xiaowei; Zhu, Gaohua; Wang, Dezhi; Gould, Ryan W; Cuff, Diana C; Tang, Ming Y; Dresselhaus, Mildred S; Chen, Gang; Ren, Zhifeng

2008-12-01

36

Surface treatment of new type aluminum lithium alloy and fatigue crack behaviors of this alloy plate bonded with Ti–6Al–4V alloy strap  

Microsoft Academic Search

Samples consisting of new aluminum lithium alloy (Al–Li alloy) plate developed by the Aluminum Company of America and Ti–6Al–4V alloy (Ti alloy) plate were investigated. Plate of 400mm×140mm×2mm with single edge notch was anodized in phosphoric solution and Ti alloy plate of 200mm×20 (40) mm×2mm was anodized in alkali solution. Patterns of two alloys were studied at original\\/anodized condition. And

Zhen-Qi Sun; Ming-Hui Huang; Guo-Huai Hu

37

On the grindability of Titanium alloy by brazed type monolayered superabrasive grinding wheels  

Microsoft Academic Search

This paper deals with an investigation of the grindability of Titanium alloy Ti–6Al–4V with monolayered brazed type superabrasive grinding wheels. The experiments, conducted under different grinding environments, showed the performance of the grinding fluids based on an evaluation of grinding forces, chip formation and tool condition. It could be found that conventional grinding fluids like oil or alkaline soap are

U. Teicher; A. Ghosh; A. B. Chattopadhyay; K. Künanz

2006-01-01

38

Analysis of the satellite spectrum in metallic alloys of CsCl type with periodic superlattice  

NASA Astrophysics Data System (ADS)

The intensity spectrum for the (h00)-type nodal reflection from the superlattice with a periodical modulated structure is analysed. The interpretation of the experimental spectrum of the Alnico alloy is made on the basis of this model, and the superlattice parameters are calculated.

Gaca, J.; Wójcik, M.; Sass, J.

1988-03-01

39

Three defect types in friction stir welding of aluminum die casting alloy  

Microsoft Academic Search

For different tool plunge downforces, the optimum FSW conditions of aluminum die casting alloy were examined. The higher the tool plunge downforce is, the wider the range of the optimum FSW conditions is. The following three different types of defects are formed, depending on the FSW conditions. (1) A large mass of flash due to the excess heat input; (2)

Y. G. Kim; H. Fujii; T. Tsumura; T. Komazaki; K. Nakata

2006-01-01

40

The Weak Localization for the Alloy-Type Anderson Model on a Cubic Lattice  

NASA Astrophysics Data System (ADS)

We consider alloy type random Schrödinger operators on a cubic lattice whose randomness is generated by the sign-indefinite single-site potential. We derive Anderson localization for this class of models in the Lifshitz tails regime, i.e. when the coupling parameter ? is small, for the energies E?- C? 2.

Cao, Zhenwei; Elgart, Alexander

2012-09-01

41

Effects of SiC Nanodispersion on the Thermoelectric Properties of p-Type and n-Type Bi2Te3-Based Alloys  

NASA Astrophysics Data System (ADS)

Polycrystalline p-type Bi0.5Sb1.5Te3 and n-type Bi2Te2.7Se0.3 thermoelectric (TE) alloys containing a small amount (vol.% ?5) of SiC nanoparticles were fabricated by mechanical alloying and spark plasma sintering. It was revealed that the effects of SiC addition on TE properties can be different between p-type and n-type Bi2Te3-based alloys. SiC addition slightly increased the power factor of the p-type materials by decreasing both the electrical resistivity ( ?) and Seebeck coefficient ( ?), but decreased the power factor of n-type materials by increasing both ? and ?. Regardless of the conductivity type, the thermal conductivity was reduced by dispersing SiC nanoparticles in the Bi2Te3-based alloy matrix. As a result, a small amount (0.1 vol.%) of SiC addition increased the maximum dimensionless figure of merit ( ZT max) of the p-type Bi0.5Sb1.5Te3 alloys from 0.88 for the SiC-free sample to 0.97 at 323 K, though no improvement in TE performance was obtained in the case of n-type Bi2Te2.7Se0.3 alloys. Importantly, the SiC-dispersed alloys showed better mechanical properties, which can improve material machinability and device reliability.

Liu, Da-Wei; Li, Jing-Feng; Chen, Chen; Zhang, Bo-Ping

2011-05-01

42

Linear augmented Slater-type orbital study of Pt5d-transition-metal alloying  

Microsoft Academic Search

We have used a self-consistent density-functional theory with an augmented Slater-type-orbital basis to calculate the heats of formation, charge components, and densities of states for ordered 5d-transition-metal-platinum alloys. Crystal structures considered were CsCl, CuAu-I, AuCd, CrB, Cu3Au, Al3Ti, MoSi2, and MoPt2, though not all structures were calculated for each alloy system. Calculated heats of formation are in accord with the

R. E. Watson; J. W. Davenport; M. Weinert

1987-01-01

43

Thermoelectric properties of some p-type half-Heusler alloys  

NASA Astrophysics Data System (ADS)

We have synthesized a series of multi-component p-type half Heusler alloys by simultaneously substituting suitable elements at different crystallographic sites. Both electrical and thermal transport properties of these alloys are studied up to 1000K to evaluate their thermoelectric potential. At 300K, typical thermopower(S) and resistivity(?) values are around ˜ 80 ?V/K and ˜1m?-cm respectively. Due to heavy substitution/doping, (?)-T behavior is similar to that of a degenerate semiconductor and the resistivity increases with increasing T with ? values in the range of few m?-cm at 1000K. Thermopower also increases with increasing T and reaches a maximum of hundreds of ?V/K at 1000K. Room temperature thermal conductivity (?) values are about ˜ 4.5 W/m-K and these ? values are low compared to those of ternary half-Heusler alloys. In well- optimized compositions, these values could improve even further.

Ponnambalam, V.; Tritt, T. M.; Zhu, Meng; Poon, S. J.

2006-03-01

44

Precipitation of an intermetallic phase with Pt2Mo-type structure in alloy 625  

NASA Astrophysics Data System (ADS)

The microstructure of Alloy 625, which has undergone prolonged (˜70,000 hours) service at temperatures close to but less than 600 °C, has been characterized by transmission electron microscopy. The precipitation of an intermetallic phase Ni2(Cr, Mo) with Pt2Mo-type structure has been observed in addition to that of the ?? phase. Six variants of Ni2(Cr, Mo) precipitates have been found to occur in the austenite grains. These particles exhibit a snowflake-like morphology and are uniformly distributed in the matrix. They have been found to dissolve when the alloy is subjected to short heat treatments at 700 °C. The occurrence of the Ni2(Cr, Mo) phase has been discussed by taking the alloy chemistry into consideration. Apart from the intermetallic phases, the precipitation of a M6C-type carbide phase within the matrix and the formation of near continuous films, comprising discrete M6C/M23C6 carbide particles, at the austenite grain boundaries have been noticed in the alloy after prolonged service.

Sundararaman, M.; Kumar, Lalit; Prasad, G. Eswara; Mukhopadhyay, P.; Banerjee, S.

1999-01-01

45

Creep behavior of the heusler type structure alloy Ni 2 AlTi  

Microsoft Academic Search

A specific method for improving the high temperature creep strength of ?-NiAl by a ternary addition giving rise to an additional\\u000a degree of order is examined. The ternary alloy thus formed has theA\\u000a 2BC or Heusler type structure, and the present study is devoted to the creep behavior of polycrystalline Ni2AlTi of stoichiometric composition. Possible slip modes are predicted on

P. R. Strutt; R. S. Polvani; J. C. Ingram

1976-01-01

46

Corrosion Potential Measurements on Type 304 SS and Alloy 182 in Simulated BWR Environments  

Microsoft Academic Search

The effects of dissolved oxygen, hydrogen, and hydrogen peroxide on the corrosion (electrochemical) potentials (ECPs) of type 304 SS and alloy 182 in simulated boiling water reactor (BWR) coolant environments under various water chemistry conditions at 288 C are reported. In oxygenated systems, the measured ECP fell within the range +20 to [minus]600 mV (vs SHE) depending on the O[sub

D. D. Macdonald; K. D. Makela; K. D. Yoshida; H. D. Song

1993-01-01

47

Infrared Absorption in Gallium Phosphide-Gallium Arsenide Alloys I. Absorption in n-type Material  

Microsoft Academic Search

There is an absorption band at 3 ?m in n-type gallium phosphide for which a number of explanations have been advanced. These are discussed, and it is shown that a distinction may be made between them by observing the 3 ?m band as a function of composition in GaPxAs1-x alloys. Experimentally it is found that at liquid nitrogen temperatures the

J W Allen; J W Hodby

1963-01-01

48

Damping properties of iron-manganese antifriction alloys with different types of crystal lattice  

Microsoft Academic Search

Conditions for ensuring a high damping capacity in high-strength low-cost antifriction materials are determined depending\\u000a on the content of manganese, methods of fabrication (traditional and powder metallurgy), and type of crystal lattice. The\\u000a mechanisms of energy dissipation in cast and powder Fe – Mn alloys are studied and the special features of their structure\\u000a responsible for the elevation of the

T. F. Volynova; M. A. Lushkin; I. K. Buravlev

2009-01-01

49

Surface treatment for inhibition of corrosion and hydrogen penetration of type 718 alloy  

SciTech Connect

Polarization and permeation experiments showed that a monolayer coverage of lead (Pb) effectively inhibited the hydrogen (H) evolution reaction and H penetration through type 718 (UNS N07718) alloy. Observed inhibition effects were a result of the kinetic limitations of the H discharge reaction and suppression of H absorption on the deposited monolayer. H evolution reaction and H permeation rates were reduced by [approximately]67% and 70%, respectively.

Popov, B.N.; Zheng, G.; White, R.E. (Univ. of South Carolina, Columbia, SC (United States). Dept. of Chemical Engineering)

1994-08-01

50

Site preference of Mg acceptors and improvement of p-type doping efficiency in nitride alloys.  

PubMed

We perform first-principles density functional calculations to investigate the effect of Al and In on the formation energy and acceptor level of Mg in group-III nitride alloys. Our calculations reveal a tendency for the Mg dopants to prefer to occupy the lattice sites surrounded with Al atoms, whereas hole carriers are generated in In- or Ga-rich sites. The separation of the Mg dopants and hole carriers is energetically more favourable than a random distribution of dopants, being attributed to the local bonding effect of weak In and strong Al potentials in alloys. As a consequence, the Mg acceptor level, which represents the activation energy of Mg, tends to decrease with increasing numbers of Al next-nearest neighbours, whereas it increases as the number of In next-nearest neighbours increases. Based on the results, we suggest that the incorporation of higher Al and lower In compositions will improve the p-type doping efficiency in quaternary alloys, in comparison with GaN or AlGaN ternary alloys with similar band gaps. PMID:23709500

Park, Ji-Sang; Chang, K J

2013-05-24

51

Electronic Structures and Magnetic Phase Stability of L10 and B2-Type MnRh Equiatomic Alloys  

NASA Astrophysics Data System (ADS)

We present magnetic properties, electronic structures and phase stability of L10- and B2-type MnRh equiatomic alloys. The calculated density of states for the L10-type equiatomic alloy in the collinear antiferromagnetic state exhibits a marked dip around the Fermi energy EF. The experimental electronic specific heat coefficient ?e of the L10-type equiatomic alloy is comparatively low of about 5.0 mJ mol-1 K-2, verifying the theoretical calculation. The effective exchange constant J0 in the collinear antiferromagnetic state is given to be about 171.9 meV, corresponding to TN=1330 K in the molecular field approximation scheme. The theoretical results predict that the antiferromagnetism of the B2-type equiatomic alloy is unstable, implying that the ground state is very weak ferromagnetic or non-magnetic. On the other hand, the total energy of the B2-type alloy in the paramagnetic state is lower than that of the L10-type alloy, being consistent with the experimental fact that a diffusionless transformation between the L10- and B2-type structures occurs below room temperature.

Umetsu, Rie Y.; Fukamichi, Kazuaki; Sakuma, Akimasa

2007-10-01

52

Electroplating of thin films of bismuth onto type 4340 steel and alloy 718 to prevent hydrogen embrittlement  

SciTech Connect

Polarization and permeation experiments showed that a thin layer of electroplated bismuth (1 {mu}m to 2 {mu}m) inhibited the evolution and penetration of hydrogen through nickel-chromium alloy 718 (UNS N07718) and type 4340 (UNS G43400) steel. Inhibition effects were due to the kinetic limitations of the hydrogen discharge reaction and to the suppression of hydrogen adsorption on the deposited layers. The hydrogen evolution reactions on alloy 718 and type 4340 steel were inhibited by 28% and 85%, respectively. The hydrogen permeation rates through these alloys were reduced by 76% and 65%, respectively.

Popov, B.N.; Zheng, G.; White, R.E. [Univ. of South Carolina, Columbia, SC (United States). Dept. of Chemical Engineering

1995-06-01

53

Determination of damage functions for the pitting of AISI type 403 blade alloy and ASTM A470\\/471 disk alloy  

Microsoft Academic Search

The prediction of pitting accumulation on turbine blades and disks is of particular importance to predict localized corrosion damages in low pressure (LP) steam turbines. Damage Function Analysis (DFA) and Deterministic Extreme Value Statistics (DEVS) have been employed to predict the pitting damage on AISI Type 403 stainless steel (SS) blade alloy and ASTM A470\\/471 disk steel in simulated LP

Yancheng Zhang

2005-01-01

54

Enhanced thermoelectric figure-of-merit in spark plasma sintered nanostructured n-type SiGe alloys  

NASA Astrophysics Data System (ADS)

We report a significant enhancement in the thermoelectric figure-of-merit of phosphorous doped nanostructured n-type Si80Ge20 alloys, which were synthesized employing high energy ball milling followed by rapid-heating using spark plasma sintering. The rapid-heating rates, used in spark plasma sintering, allow the achievement of near-theoretical density in the sintered alloys, while retaining the nanostructural features introduced by ball-milling. The nanostructured alloys display a low thermal conductivity (2.3 W/mK) and a high value of Seebeck coefficient (-290 ?V/K) resulting in a significant enhancement in ZT to about 1.5 at 900 °C, which is so far the highest reported value for n-type Si80Ge20 alloys.

Bathula, Sivaiah; Jayasimhadri, M.; Singh, Nidhi; Srivastava, A. K.; Pulikkotil, Jiji; Dhar, Ajay; Budhani, R. C.

2012-11-01

55

Linear Wegner estimate for alloy-type Schrödinger operators on metric graphs  

NASA Astrophysics Data System (ADS)

We study spectra of alloy-type random Schrödinger operators on metric graphs. For finite edge subsets we prove a Wegner estimate which is linear in the volume (i.e., the total length of the edges) and the length of the energy interval. The single site potential needs to have fixed sign; the metric graph does not need to have a periodic structure. A further result is the existence of the integrated density of states for ergodic random Hamiltonians on metric graphs with a Z? structure. For certain models the two above results together imply the Lipschitz continuity of the integrated density of states.

Helm, Mario; Veseli?, Ivan

2007-09-01

56

Development of casting investment preventing blackening of noble metal alloys Part 2. Application of developed investment for type 4 gold alloy.  

PubMed

The objective of this study was to evaluate the efficacy of the developed investment for the prevention of blackening of a cast Type 4 gold and to analyze the oxides on its surface in relation to the blackening of the alloy. The experimental investments were prepared using a gypsum-bonded investment in which boron (B) or aluminum (Al) was added as a reducing agent. A Type 4 gold alloy was cast into the mold made of the prepared investment. The effect of the additives was evaluated from the color difference (deltaE*) between the as-cast surface and the polished surface of the cast specimen. B and Al were effective to prevent the blackening of a Type 4 gold alloy and the color of the as-cast surface approached that of the polished surface with increasing B and Al content. The prevention of the blackening of the gold alloy can be achieved by restraining the formation of CuO. PMID:14620998

Nakai, Akira; Kakuta, Kiyoshi; Goto, Shin-ichi; Kato, Katuma; Yara, Atushi; Ogura, Hideo

2003-09-01

57

High-temperature ductility of nickel alloys type KhN55MBYu with a high iron content  

Microsoft Academic Search

In order to prepare stamped and welded structures which operate in the temperature range from 750 to -253°C there is use of high-strength dispersion-hardening nickel alloys KhN55MBYu (ÉP666) and KhN58MBYuD (ÉK61) which exhibit resistance to hot crack formation during welding and cracking of welded joints during defonnation. Alloys of this type have a high level of strength (sf = 1300

N. A. Sorokina; V. I. Gal'tsova

1994-01-01

58

The effect of solidification rate on the growth of small fatigue cracks in a cast 319-type aluminum alloy  

Microsoft Academic Search

A study was conducted to investigate the effect of solidification rate on the growth behavior of small fatigue cracks in a\\u000a 319-type aluminum alloy, a common Al-Si-Cu alloy used in automotive castings. Fatigue specimens were taken from cast material\\u000a that underwent a hot isostatic pressing (HIP) process in order to eliminate shrinkage pores and to facilitate the observation\\u000a of surface-initiated

M. J. Caton; J. Wayne Jones; J. M. Boileau; J. E. Allison

1999-01-01

59

The effect of solidification rate on the growth of small fatigue cracks in a cast 319-type aluminum alloy  

Microsoft Academic Search

A study was conducted to investigate the effect of solidification rate on the growth behavior of small fatigue cracks in a 319-type aluminum alloy, a common Al-Si-Cu alloy used in automotive castings. Fatigue specimens were taken from cast material that underwent a hot isostatic pressing (HIP) process in order to eliminate shrinkage pores and to facilitate the observation of surface-initiated

M. J. Caton; J. Wayne Jones; J. M. Boileau; J. E. Allison

1999-01-01

60

Effect of the mode of plastic deformation on the formation of the alloy-type texture  

SciTech Connect

The aim of this work was to explore the role of heterogeneous deformation in the formation of the alloy-type texture. Recent works on the role of the deformation mode in evolution of the deformation texture seem to shed new light on the problem of texture formation. In particular it has been shown, that the texture typical for pure fcc metals (copper type texture), may be easily converted into the B-component of the alloy type texture (brass texture) due to shear banding induced during cross-rolling. It was proved that deformation in shear bands is a simple transgranular shear (micro-shearband) which makes the polycrystalline metal behave like a single crystal oriented for the single system slip. In view of these results, it seems necessary to re-examine the problem of the formation of the brass type texture during monotonic rolling. In particular, there is no experimental information about the spatial orientation of shear bands in the test piece of brass, except that they occurs on average on lateral face of sample, at 35{degree} with respect to the rolling direction. This does not suffice yet to conclude whether the position of shear in brass is the same as in copper. It may as well be expected, that if the deformation in shear bands in brass is not a plane strain deformation with respect to the sample reference system or, in other words, the sample transverse direction does not lie in the plane of shear, the formation of shear bands may systematically lead to splitting of the metal type texture (resulting from homogeneous deformation) according to the geometry of shear bands. The problem of the spatial orientation of shear bands in monotonically rolled brass and of the evolution of the texture pattern is discussed in this work.

Dobrzanski, F.; Bochniak, W. [Akademy of Mining and Metallurgy, Krakow (Poland). Dept. of Structure and Mechanics of Solids

1995-06-15

61

Highly Conductive p-Type Silicon Carbon Alloys Deposited by Hot-Wire Chemical Vapor Deposition  

NASA Astrophysics Data System (ADS)

P-type microcrystalline silicon carbide (?c-SiC:H) alloys for application as a window layer in silicon based thin film solar cells were grown by hot-wire chemical vapor deposition using hydrogen diluted monomethylsilane and trimethylaluminum. Conductivities up to 0.1 S/cm were obtained for p-type material. The optical properties were studied by photothermal deflection spectroscopy. At photon energies below 1.25 eV, both free carrier and defect absorption lead to a high absorption coefficient. For photon energies >2.0 eV, the absorption coefficient is affected by the crystallinity and the structural composition. The structure of Al-doped ?c-SiC:H thin films were investigated by infrared and Raman spectroscopy. It was found that increase of the deposition pressure can compensate for the loss of crystallinity caused by Al-doping. At high deposition pressure (>100 Pa), increasing contributions of hexagonal SiC alloys, and separated carbon phases are observed.

Tao Chen,; Deren Yang,; Reinhard Carius,; Friedhelm Finger,

2010-04-01

62

Use of inoculants to refine weld solidification structure and improve weldability in type 2090 Al?Li alloy  

Microsoft Academic Search

The refinement of weld solidification structures will be useful not only because it is known to reduce the tendency to hot cracking, but also because the mechanical properties of the fusion zone are likely to be improved. In the current work, welds were produced in a type 2090 Al?Li alloy using two filler materials based on types 2319 and 4043.

G. D Janaki Ram; T. K Mitra; M. K Raju; S Sundaresan

2000-01-01

63

Finite element analysis of the needle type applicator made of shape memory alloy.  

PubMed

In this paper, we propose a new heating method in which we use shape memory alloy (SMA) in a needle type applicator for brain tumor hyperthermia. In order to expand the heating area of a needle type applicator and to control the heating pattern for various sizes of tumors, some kinds of SMA needle type applicators were developed. To apply the proposed heating method safely to clinical hyperthermia, it is necessary to make appropriate thermal distribution to the region of the brain tumor. However, it is not easy to predict the three dimensional temperature distribution during the human brain tumor hyperthermia. Therefore, we estimated the temperature distribution inside the agar phantom by the finite element method (FEM). Here, first, the computer simulation results of temperature distributions under the different heating times are discussed. Second, a comparison of the heating properties obtained by using the needle type electrodes made of different shaped SMA is discussed. From these results, it is confirmed that the proposed heating method can expand the heating area and control the heating pattern for the various sizes of brain tumors. PMID:19163680

Yabuhara, T; Kato, K; Kanazawa, Y; Kubo, M; Takahashi, H; Uzuka, T; Fujii, Y

2008-01-01

64

Some Factors Affecting the Metallurgical Microstructure and Creep Properties of the Titanium 3 al 6 SN 5 Zr 0.5 Si Type of Alloy.  

National Technical Information Service (NTIS)

Optical and electron metallographic techniques have been used to study the microstructure of Titanium 3Al 6Sn 5Zr 0.5 Si type alloy (Hylite 55) and Titanium 3Al 6Sn 5Zr 2 Mo 0.5 Si type alloy (Hylite 60) containing 0.005 wt %, 0.42 wt % and 0.75 wt % Si a...

C. R. Mayo M. A. P. Dewey P. A. Dow W. K. Armitage

1966-01-01

65

Consolidation and thermoelectric properties of n-type bismuth telluride based materials by mechanical alloying and hot pressing  

Microsoft Academic Search

Bismuth telluride based n-type thermoelectric materials were prepared via the route of mechanical alloying (MA) and subsequent hot pressing (HP) process. Influence of hot press process parameters on the thermoelectric properties was investigated. Increasing hot pressing temperature from 340 to 400°C, the figure of merit of the hot pressed sample increases rapidly, and then it grows slowly and no improvement

J. Y. Yang; X. A. Fan; R. G. Chen; W. Zhu; S. Q. Bao; X. K. Duan

2006-01-01

66

ROLL CLADDING URANIUM-ZIRCONIUM AND URANIUM-ZIRCONIUM-NIOBIUM ALLOYS WITH ZIRCALOY2 FOR PLATE-TYPE FUEL ELEMENTS  

Microsoft Academic Search

Clad plate-type fuel elements containing U--5 wt.% Zr--1.5 wt.% Nb alloy ; cores integrally clad on all surfaces with Zircaloy-2 were developed for the ; Experimental Boiling Water Reactor (EBWR). These plates were prepared by roll ; bonding assembled components inside steel jackets at 850 deg C with 50% reduction ; in thickness to effect sound diffusion bonds at all

C. H. Bean; R. E. Macherey; J. R. Lindgren

1958-01-01

67

Impact Tensile Properties of Friction Welded Butt Joints between 6061 Aluminum Alloy and Type 304 Stainless Steel  

Microsoft Academic Search

The tensile strength and energy absorption for dissimilar metal friction welds between 6061 Al alloy and Type 304 stainless steel at high rates of loading are determined using the split Hopkinson bar. Cylindrical tensile specimens machined from as-welded butt joints of 13 mm in diameter are used in both static and impact tests. Friction welding is conducted using a brake

Takashi Yokoyama

2003-01-01

68

Fabrication of L1{sub 1} type Co-Pt ordered alloy films by sputter deposition  

SciTech Connect

L1{sub 1} type Co-Pt ordered alloy films with a large uniaxial magnetic anisotropy, K{sub u}, of the order of 10{sup 7} erg/cm{sup 3} were successfully fabricated at relatively low substrate temperatures of 270-390 deg. C using ultrahigh vacuum sputter film deposition. L1{sub 1} type ordered Co-Pt films, with the <111> direction (easy axis of magnetization) perpendicular to the film plane, were fabricated on MgO(111) single crystal substrates and glass disks. The ordered structure was formed in a wide Pt content region of 40-75 at. %, and K{sub u} showed a maximum at around 50 at. % Pt content. The values of the order parameter S and K{sub u} for L1{sub 1} type Co{sub 50}Pt{sub 50} films increased as the substrate temperature T{sub s}, increased. K{sub u} reached about 3.7x10{sup 7} erg/cm{sup 3} (S=0.54) at T{sub s}=360 deg. C for the single crystal films deposited on MgO(111) substrates, indicating a potential increase in K{sub u} by enhancing the ordering. The values of K{sub u} for polycrystalline films deposited on glass disks were smaller than those for the single crystal films on MgO(111) substrates, however, K{sub u} reached 1.9x10{sup 7} erg/cm{sup 3} at T{sub s}=360 deg. C. The experimental results demonstrate the potential of L1{sub 1} type Co{sub 50}Pt{sub 50} films for use in data storage applications, because of their very high K{sub u}, comparable to L1{sub 0} type Fe{sub 50}Pt{sub 50} films, the relatively low fabrication temperature, and good controllability of the grain orientation.

Sato, H.; Shimatsu, T.; Okazaki, Y.; Muraoka, H.; Aoi, H.; Okamoto, S.; Kitakami, O. [Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Institute of Multidisciplinary Research for Advanced Material, Tohoku University, Sendai 980-8577 (Japan)

2008-04-01

69

Galvanic effects accelerate crevice corrosion of type 316L SS flanges coupled to 6% Mo alloy. [Stainless Steel  

Microsoft Academic Search

A service water system underwent a material replacement program in recent years. The service was a once-through system fed from the Delaware River. The original type 316L stainless steel (SS) and cement-lined carbon steel were replaced with 6% Mo alloy AL-6XN (UNS N08367). The majority of the system was 6% Mo piping connected to type 316L SS valves via gasketed

1999-01-01

70

Al-Si alloy formation in narrow p-type Si contact areas for rear passivated solar cells  

NASA Astrophysics Data System (ADS)

For high efficiency silicon solar cells, the rear surface passivation by a dielectric layer has significant advantages compared to the standard fully covered Al back-contact structure. In this work the rear contact formation of the passivated emitter and rear cell device structure is analyzed. Contrary to expected views, we found that the contact resistivity of fine screen printed Al fingers alloyed on narrow p-type Si areas depends on the geometry of the Al-Si alloy formation below the contacts, and decreases by reducing the contact area, while the contact resistance remains constant. At the solar cell level, the reduction in the contact resistivity leads to a minimization of the fill factor losses. At the same time, narrow Al-Si alloy formations increased the passivated area below the contacts, improving the optical properties of the rear side, reducing the short-circuit current and open-circuit voltage losses. Scanning electron microscopy analysis of the Al-Si alloy geometry is performed, in order to understand its influence on the contact resistivity. The analysis presented in this article has application in Al-Si alloying processes and advanced solar cells concepts, like back-contact and rear passivated solar cells.

Urrejola, Elias; Peter, Kristian; Plagwitz, Heiko; Schubert, Gunnar

2010-06-01

71

Valence Band Structure of Highly Efficient p-type Thermoelectric PbTe-PbS Alloys  

SciTech Connect

New experimental evidence is given relevant to the temperature-dependence of valence band structure of PbTe and PbTe1-xSx alloys (0.04 x 0.12), and its effect on the thermoelectric figure of merit zT. The x = 0.08 sample has zT ~ 1.55 at 773K. The magnetic field dependence of the high-temperature Hall resistivity of heavily p-type (> 1019 cm-3) Na-doped PbTe1-xSx reveals the presence of high-mobility electrons. This put in question prior analyses of the Hall coefficient and the conclusion that PbTe would be an indirect gap semiconductor at temperatures where its zT is optimal. Possible origins for these electrons are discussed: they can be induced by photoconductivity, or by the topology of the Fermi surface when the L and -bands merge. Negative values for the low-temperature thermopower are also observed. Our data show that PbTe continues to be a direct gap semiconductor at temperatures where the zT and S2 of p-type PbTe are optimal e.g. 700-900K. The previously suggested temperature induced rapid rise in energy of the heavy hole LVB relative to the light hole UVB is not supported by the experimental data.

Jaworski, C. M. [Ohio State University; Nielsen, Mechele [Ohio State University; Wang, Hsin [ORNL; Girard, Steven N. [Northwestern University, Evanston; Cai, Wei [ORNL; Porter, Wallace D [ORNL; Kanatzidis, Mercouri G. [Northwestern University, Evanston; Heremans, J. P. [Ohio State University

2013-01-01

72

Effects of temperature on crack growth rate in sensitized type 304 stainless steel and alloy 600  

SciTech Connect

Effects of temperature on stress corrosion crack growth rates were studied on three heats of sensitized type 304 (UNS S30400) stainless steel (SS) and one heat of sensitized alloy 600 (UNS N06600). Data were obtained using reversed direct current (DC) potential drop crack length monitoring on 25-mm compact-type (CT) specimens in 25 C. to 288 C. water, usually containing 200 ppb oxygen (O[sub 2]). Most data were obtained in 0.3 [mu]M sulfuric acid. In one heat, 0.1[mu]M hydrochloric acid, 0.5 [mu]M HCI, and air-saturated water also were evaluated. All heats and materials had similar temperature dependence and showed a peak in crack growth rate at [approximately] 200 C. in these water chemistries, which typically was a factor of 30 to 100 times higher than at 288 C. or 25 C. Growth rates decreased rapidly above 250 C. compared to those between 25 C. and 200 C. In many cases, similar rates were observed at 25 C. and 288 C. Data were compared with the literature on fracture mechanics and slow strain rate specimens. Issues in determining the value and origin of apparent activation energies also were discussed.

Andresen, P.L. (GE Corporate Research and Development Center, Schenectady, NY (United States))

1993-09-01

73

Short-range order types in binary alloys: A reflection of coherent phase stability  

SciTech Connect

The short-range order (SRO) present in disordered solid solutions is classified according to three characteristic system-dependent energies: (1) formation enthalpies of ordered compounds, (2) enthalpies of mixing of disordered alloys, and (3) the energy of coherent phase separation, (the composition-weighted energy of the constituents each constrained to maintain a common lattice constant along an A/B interface). These energies are all compared against a common reference, the energy of incoherent phase separation (the composition-weighted energy of the constituents each at their own equilibrium volumes). Unlike long-range order (LRO), short-range order is determined by energetic competition between phases at a fixed composition, and hence only coherent phase-separated states are of relevance for SRO. The authors find five distinct SRO types, and show examples of each of these five types, including Cu-Au, Al-Mg, GaP-InP, Ni-Au, and Cu-Ag. The SRO is calculated from first-principles using the mixed-space cluster expansion approach combined with Monte Carlo simulations. Additionally, they examine the effect of inclusion of coherency strain in the calculation of SRO, and specifically examine the appropriate functional form for accurate SRO calculations.

W. Wolverton; V. Ozolins; Alex Zunger

1999-11-23

74

Galvanic effects accelerate crevice corrosion of type 316L SS flanges coupled to 6% Mo alloy. [Stainless Steel  

SciTech Connect

A service water system underwent a material replacement program in recent years. The service was a once-through system fed from the Delaware River. The original type 316L stainless steel (SS) and cement-lined carbon steel were replaced with 6% Mo alloy AL-6XN (UNS N08367). The majority of the system was 6% Mo piping connected to type 316L SS valves via gasketed flanges. During several years of operation, plant personnel observed localized crevice corrosion on the flange-face areas of the type 316L SS (UNS S31603) flanges. This area typically contains an insulation gasket material (a fibrous bound elastomeric material) that is sandwiched between flange joints. Galvanic effects, caused by the mixed alloy construction (i.e., type 316L SS to alloy 6% Mo), may be accelerating the observed crevice corrosion of type 316L SS. This possibility was of significant concern, and flange isolation kits typically used for isolating cathodic protection systems or dissimilar metals were being used. However, the plant grounding system caused the isolated flanges to have zero electrical resistance between them.

Krantz, B. (Corrosion Testing Labs., Inc. (United States))

1999-06-01

75

Fatigue strength of titanium alloys with a VK-type detonation coating  

Microsoft Academic Search

The influence of the structural, phase, and size factors, and the bonding of hard tungsten alloys to titanium alloy bases on the mechanism by which the system fails under alternating loads is studied. The failure mechanism of materials with detonation coatings applied by different methods is discussed in regard to the classical sequence of fatigue phenomena, i.e., hardening-softening and crack

V. K. Fedorenko; V. V. Sergeev; I. N. Shkanov; V. S. Klimenko; A. M. Il'chenko; T. A. Il'inkova

1995-01-01

76

Effect of Mg and Sr-modification on the mechanical properties of 319-type aluminum cast alloys subjected to artificial aging  

Microsoft Academic Search

Aluminum-based 319-type cast alloys are commonly used in the automotive industry to manufacture cylinder heads and engine blocks. These applications require good mechanical properties and in order to achieve them through precipitation hardening, artificial aging treatments are applied to the products. The standard artificial aging treatment for alloy 319, as defined by the T6 heat treatment temper, consists in solution

F. J. Tavitas-Medrano; J. E. Gruzleski; F. H. Samuel; S. Valtierra; H. W. Doty

2008-01-01

77

Dot arrays of L1{sub 1} type Co-Pt ordered alloy perpendicular films  

SciTech Connect

Magnetic properties of dot arrays of L1{sub 1} type Co-Pt ordered alloy perpendicular films were studied. L1{sub 1}-Co-Pt films with a large uniaxial magnetic anisotropy K{sub u} of the order of 10{sup 7} erg/cm{sup 3} were fabricated at a substrate temperature of 360 deg. C using ultrahigh vacuum sputter film deposition. Dot patterns with dot diameters of 70-200 nm were made using high resolution e-beam lithography and reactive ion etching (RIE). The values of K{sub u} were measured by the GST method using the Anomalous Hall Effect; we observed the averaged signals of 6000 dots. The values of K{sub u} for dot arrays of 10-nm-thick L1{sub 1}-Co{sub 50}Pt{sub 50} films deposited on MgO(111) substrates (single crystal films) and glass disks (polycrystalline films) were nearly the same as those of the original films independent of D, indicating no significant etching damage by the RIE process. Magnetic force microscopy images revealed that all dots were single domains in the present D region. The coercivity H{sub c} of the dot arrays was 25.0 kOe [MgO(111) substrate, D=70 nm] and 14.3 kOe (glass disks, D=80 nm). The switching field distribution {sigma}/H{sub c} was relatively small, {sigma}/H{sub c}=0.15, even for dot arrays fabricated on glass disks, indicating the homogeneous formation of a L1{sub 1} type ordered structure in the Co{sub 50}Pt{sub 50} layers.

Shimatsu, T.; Mitsuzuka, K.; Aoi, H. [Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Sato, H. [Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Institute of Multidisciplinary Research for Advanced Material, Tohoku University, Sendai 980-8577 (Japan); Kataoka, H. [Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Fuji Electric Device Technology, Co., Ltd., Matsumoto 390-0821 (Japan); Okamoto, S.; Kitakami, O. [Institute of Multidisciplinary Research for Advanced Material, Tohoku University, Sendai 980-8577 (Japan)

2009-04-01

78

Enhancement of light reflectance and thermal stability in Ag-Cu alloy contacts on p-type GaN  

Microsoft Academic Search

The mechanism for thermally stable Ag-Cu alloy Ohmic contact on p-type GaN was investigated. Ag-Cu contact showed lower contact resistivity as low as 8.6×10-6 Omega cm2, higher reflectance of 84% at 460 nm, and better thermal stability than Ag contact after annealing in air ambient. The formation of Ag-Ga solid solution lowered the contact resistivity. Additionally the formation of Cu

Jun Ho Son; Gwan Ho Jung; Jong-Lam Lee

2008-01-01

79

Neutron irradiation damage of helium-charged V?Ti?Cr?Si-type alloys  

NASA Astrophysics Data System (ADS)

The V?25Ti?15Cr?1Si?(0.5Al?1Y) and V?5Ti?5Cr?1Si?(1Al?1Y) alloys with helium implanted by the tritium-trick technique were irradiated at 679, 793 and 873 K to ?40 dpa in FFTF/MOTA. The helium-implanted alloys swelled significantly more than alloys without helium. In the case of the V?2STi?15Cr?1Si alloy irradiated at 679 K, cavities were mainly observed on the grain boundaries with small diameter cavities surrounding larger diameter cavities. At higher irradiation temperatures, large cavities were distributed uniformly in the matrix. The influence of knock-on helium atoms on cavity distribution is discussed.

Satou, M.; Abe, K.; Matsui, H.

1992-09-01

80

Study of the corrosion resistance of Cr, Zr, Y doped AB 5 type alloys in KOH  

Microsoft Academic Search

The effect of partial substitutions of Y, Zr or Cr on the chemical stability of AB5+x alloys in concentrated KOH aqueous solution was investigated. Alloys were elaborated using conventional casting, rapid cooling or gas atomisation, then heat-treated and characterised in terms of chemical composition, microstructure (MEB, XRD), electrochemical performances and corrosion resistance in a 8.7 M KOH solution at 70°C.

O Arnaud; P Barbic; P Bernard; A Bouvier; B Knosp; B Riegel; M Wohlfahrt-Mehrens

2002-01-01

81

A revised model for the metallurgical behavior of 2:17-type permanent magnet alloys  

SciTech Connect

The 2:17 magnet alloys form a complex metallurgical system with a large number of interactive compositional and heat-treating variables. A model for the metallurgical behavior of these alloys was proposed by the author in 1983. Subsequent experiments designed to test that model have verified some aspects, significantly modified others, and added much detail. The current version of the model is reported.

Ray, A.E. (University of Dayton, Dayton, Ohio 45469-0001 (USA))

1990-05-01

82

Read/write characteristics of a new type of bit-patterned-media using nano-patterned glassy alloy  

NASA Astrophysics Data System (ADS)

The paper reports a feasibility study of new type bit-patterned-media using a nano-patterned glassy alloy template for ultra-high density hard disk applications. The prototype bit-patterned-media was prepared using a nano-hole array pattern fabricated on a Pd-based glassy alloy thin film and a Co/Pd multilayered film filled in the nano-holes. The prepared prototype bit-patterned-media had a smooth surface and isolated Co/Pd multilayer magnetic dots, where the average dot diameter, the average dot pitch and the average dot height were 30, 60 and 19 nm, respectively. MFM (magnetic force microscope) observation revealed that each dot was magnetized in a perpendicular direction and the magnetization could reverse when an opposite magnetic field was applied. Static read/write tester measurements showed that repeated writing and reading on isolated magnetic dots were possible in combination with conventional magnetic heads and high-accuracy positioning technologies. The present study indicates that the new type of bit-patterned-media composed of nano-hole arrays fabricated on glassy alloy film template and Co/Pd multilayer magnetic dots are promising for applications to next generation ultra-high density hard disk drives.

Takenaka, Kana; Saidoh, Noriko; Nishiyama, Nobuyuki; Ishimaru, Manabu; Futamoto, Masaaki; Inoue, Akihisa

2012-04-01

83

Simulations of structure formation in B2 type ordering with two step phase separation in Fe-Ni-Al alloys  

NASA Astrophysics Data System (ADS)

The present authors recently developed a time-dependent Ginzburg-Landau (TDGL) formulation for ordering processes of B2 and D03 in binary alloys, taking into account the symmetrical relationships between these ordered phases. In this formulation, mean-field free energies are defined in a form of Landau type expansion with order parameters and a composition parameter. Interfacial energies due to local variations of degrees of order and composition are given in a gradient square approximation. Kinetic equations for time-evolution of the order parameters and the composition one are derived from the Ginzburg-Landau type potential consisting of the mean-field free energies and the interfacial energy terms. On the other hand, coauthors have investigated domain structures in two-step phase separation of Fe-based Fe-Ni-Al alloys. Micro-structures in the super alloys consist of B2 ordered domains and A2 disordered matrices in the first stage of phase separation. The second stage during a subsequent aging leads to formation of B2 domains and A2 phase regions in the former A2 matrices and B2 domains, respectively. The evolution of three-dimensional domain structures and composition profiles has been analyzed by electron tomography imaging and energy-dispersive X-ray spectroscopy. In this work the authors have applied the TDGL formulation to this alloy system, and performed three-dimensional numerical simulations assuming the thermal processing. The results of the simulations well reproduced the characteristics of the micro-structures obtained from the observations.

Oguma, Ryuichiro; Matsumura, Syo; Doi, Minoru; Hata, Satoshi; Ogata, Keisuke

2013-02-01

84

Alloys for prosthodontic restorations  

Microsoft Academic Search

The numbers and types of alloys for prosthodontic restorations have increased dramatically over the past 25 years, making selection of an alloy for a given clinical situation difficult. Factors such as cost, the need for better strength, and worries about alloy corrosion have pressured the alloy market to change significantly. A number of properties—including yield strength, hardness, elastic modulus, microstructural

John C. Wataha

2002-01-01

85

Theoretical analysis of phase transformations in Fe-Ni ''Invar''-type alloys  

SciTech Connect

Many studies have suggested that Fe-Ni and Fe-Ni-Cr alloys of ca. 35 at. % Ni are susceptible to decomposition into two FCC phases. We herein model the kinetics and thermodynamics of spinodal decomposition, nucleation, growth, and coarsening of these alloys. Prediction of the scale of a microstructure formed by growth or coarsening may be done with some confidence. The absence of a model for surface energy and gradient energy in systems with negative departure from ideality reduce us to little more than guesses for the kinetics of nucleation and of spinodal decomposition. We combine our calculations with those of others and studies of terrestrial and celestial decomposition to suggest a miscibility gap for Fe-Ni alloys. The gap is very narrow at high temperatures but is broadened at low temperatures by magnetic effects. 29 refs., 15 figs.

Russell, K.C.; Garner, F.A.

1989-02-01

86

Age Hardening Kinetics in 7xxx Type (Al-Mg-Zn) Alloys  

SciTech Connect

Age hardening in industrial 7xxx alloys at the temperature 100 deg. and 150 deg. C up to 144 hrs, after solid solution treatments at 450 deg. and 550 deg. C, has been followed by measurements of Vickers hardness, scanning and transmission electron microscopy. The influence of silicon on phase and kinetic of age hardening zones and precipitates has been studied. High iron and silicon content increase the number of primary particle in the alloy. Size distribution of {eta}'-precipitates has been determined.

Vevecka-Priftaj, A. [Department of Physic, Polytechnic University of Tirana, Sheshi 'Nene Tereza', N.4, Tirana (Albania); Lamani, E. [Department of Production and Menagement, Polytechnic University of Tirana (Albania); Fjerdingen, J. [Vitec AS, Akervegen2, 7650 Verdal (Norway); Langsrud, Y. [Hydro Aluminum Structures, Raufoss, P.O.Box 15, N-2831 Raufoss (Norway); Gjoennes, J. [Center for Materials Science, University of Oslo, Gaustadalleen 21, N-0349, Oslo (Norway); Hansen, V. [Faculty of Science and Technology, University of Stavanger, N-403, Stavanger (Norway)

2007-04-23

87

Metallography and resistivity measurements on a 2–17 type alloy  

Microsoft Academic Search

Metallography and electrical resistivity measurements (?\\u000a t\\u000a \\/?\\u000a o\\u000a ) were carried out on an isothermally aged bulk alloy with a substitution composition of Sm(Co0.67Cu0.08Fe0.22Zr0.028)8.45. The as-cast alloy was found to consist of four phases: (A) zirconium-rich phase, (B) samarium- and copper-rich phase, (C)\\u000a cobalt- and iron-rich phase, and (D) very rich in zirconium phase. After annealing at 1170 C

F. Gencer; I. R. Harris

1991-01-01

88

Metallography and resistivity measurements on a 2–17 type alloy  

Microsoft Academic Search

Metallography and electrical resistivity measurements (?t\\/?o) were carried out on an isothermally aged bulk alloy with a substitution composition of Sm(Co0.67Cu0.08Fe0.22Zr0.028)8.45. The as-cast alloy was found to consist of four phases: (A) zirconium-rich phase, (B) samarium- and copper-rich phase, (C) cobalt- and iron-rich phase, and (D) very rich in zirconium phase. After annealing at 1170 °C for 5 h, phase

F. Gencer; I. R. Harris

1991-01-01

89

Titanium alloy production technology, market prospects and industry development  

Microsoft Academic Search

Titanium alloy with a low density, high specific strength, corrosion resistance and good process performance, is the ideal structural materials for the aerospace engineering. Based on the microstructure of titanium alloys, it can be divided into ?-type titanium alloys (heat-resistant titanium alloys), ?-type titanium alloys and ?+?-type titanium alloys. The research scopes also include the fabrication technology of titanium alloys,

Chunxiang Cui; BaoMin Hu; Lichen Zhao; Shuangjin Liu

2011-01-01

90

The formation of the magnetic moments in disordered binary alloys of metal-metalloid type  

Microsoft Academic Search

The s-d model of disordered binary alloy with the Hubbard electron interaction is considered in the paper. The dependence of the local magnetic moment on the number of nonmagnetic atoms in the nearest neighborhood is received as a result of the solution of the self-consistent equation for the local magnetic moment. It is shown that the model proposed describes qualitatively

A. K. Arzhnikov; L. V. Dobysheva

1992-01-01

91

Effect of cryogenic temperatures on mechanical properties of experimental alloys of the AMg6N type  

Microsoft Academic Search

Conclusions 1.The mechanical properties of AMg6N alloys and welded joints vary mainly with the testing temperature. When the temperature is lowered to -269° the strength characteristics increase, the toughness decreases, and the ductility remains at practically the same level as at standard temperature, reaching a maximum value at the temperature of liquid nitrogen. The ultimate tensile strength and the yield

A. Ya. Ishchenko; M. I. Saenko; M. R. Yavorskaya; G. B. Vasil'eva; N. V. Novikov; N. I. Gorodyskii; A. L. Maistrenko

1975-01-01

92

The effect of solidification rate on the growth of small fatigue cracks in a cast 319-type aluminum alloy  

SciTech Connect

A study was conducted to investigate the effect of solidification rate on the growth behavior of small fatigue cracks in a 319-type aluminum alloy, a common Al-Si-Cu alloy used in automotive castings. Fatigue specimens were taken from cast material that underwent a hot isostatic pressing (HIP) process in order to eliminate shrinkage pores and to facilitate the observation of surface-initiated cracks by replication. Naturally initiated surface cracks ranging in length from 17 {micro}m to 2 mm were measured using a replication technique. Growth rates of the small cracks were calculated as a function of the elastic stress-intensity-factor range ({Delta}K). Long-crack growth-rate data (10 mm {le} length {le} 25 mm) were obtained from compact-tension (CT) specimens, and comparison to the small-crack data indicates the existence of a significant small-crack effect in this alloy. The solidification rate is shown to have a significant influence on small-crack growth behavior, with faster solidification rates resulting in slower growth rates at equivalent {Delta}K levels. A stress-level effect is also observed for both solidification rates, with faster growth rates occurring at higher applied-stress amplitudes at a given {Delta}K. A crack-growth relation proposed by Nisitani and others is modified to give reasonable correlation of small-crack growth data to different solidification rates and stress levels.

Caton, M.J.; Jones, J.W.; Boileau, J.M.; Allison, J.E.

1999-12-01

93

The effect of solidification rate on the growth of small fatigue cracks in a cast 319-type aluminum alloy  

NASA Astrophysics Data System (ADS)

A study was conducted to investigate the effect of solidification rate on the growth behavior of small fatigue cracks in a 319-type aluminum alloy, a common Al-Si-Cu alloy used in automotive castings. Fatigue specimens were taken from cast material that underwent a hot isostatic pressing (HIP) process in order to eliminate shrinkage pores and to facilitate the observation of surface-initiated cracks by replication. Naturally initiated surface cracks ranging in length from 17 µm to 2 mm were measured using a replication technique. Growth rates of the small cracks were calculated as a function of the elastic stress-intensity-factor range (? K). Long-crack growth-rate data (10 mm?length?25 mm) were obtained from compact-tension (CT) specimens, and comparison to the small-crack data indicates the existence of a significant small-crack effect in this alloy. The solidification rate is shown to have a significant influence on small-crack growth behavior, with faster solidification rates resulting in slower growth rates at equivalent ? K levels. A stress-level effect is also observed for both solidification rates, with faster growth rates occurring at higher applied-stress amplitudes at a given ? K. A crack-growth relation proposed by Nisitani and others is modified to give reasonable correlation of small-crack growth data to different solidification rates and stress levels.

Caton, M. J.; Jones, J. Wayne; Boileau, J. M.; Allison, J. E.

1999-12-01

94

Characterization of corrosion products of AB{sub 5}-type hydrogen storage alloys for nickel-metal hydride batteries  

SciTech Connect

To better understand the decrease in storage capacity of AB{sub 5}-type alloys in rechargeable Ni/MH batteries undergoing repeated charge/discharge cycles, the corrosion of a MnNi{sub 3.55}Co{sub 0.75}Mn{sub 0.4}Al{sub 0.3} alloy in aqueous KOH electrolyte was studied. The crystal structure, chemical composition, and distribution of corrosion products were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Hollow and filed needles of a mixed rare earth hydroxide Mn(OH){sub 3} were found to cover a continuous nanocrystalline corrosion scale composed of metal (Ni, Co) solid solution, oxide (Ni,Co)O solid solution and rare earth hydroxide, and a Mn-depleted alloy subscale. Corrosion kinetics were measured for three different temperatures. Growth kinetics of the continuous corrosion scale and of the Mm(OH){sub 3} needles obeyed linear and parabolic rate laws, respectively. Models for the corrosion mechanism were developed on the basis of diffusional transport of Mn and OH through the hydroxide needles and subsequent diffusion along grain boundaries through the nanocrystalline scale.

Maurel, F.; Knosp, B.; Backhaus-Ricoult, M.

2000-01-01

95

Carrier concentration modulation by hot pressing pressure in n-type nanostructured Bi(Se)Te alloy  

NASA Astrophysics Data System (ADS)

We demonstrate experimentally that an optimal hot pressing pressure is required for high thermoelectric power factor in different n-type Bi(Se)Te alloys for a given processing temperature. This phenomenon is attributed to the variations in carrier concentration, which changes the Seebeck coefficient and therefore the power factor. The variations could arise from the difference in the concentration of charged antisite defects as their formation energy changes with pressures. Furthermore, modifications of the energy gap resulting from the lattice distortions at high pressure also likely play a role.

Chan, Tsung-ta E.; LeBeau, James M.; Venkatasubramanian, Rama; Thomas, Peter; Stuart, Judy; Koch, Carl C.

2013-09-01

96

Status of {ital p}-type SiGe alloys with nanophase inclusions  

SciTech Connect

Transport models have predicted that the thermal conductivity of SiGe alloys could be appreciably reduced by incorporating discrete 40 A particles within the SiGe grains. These particles would scatter the thermal phonons which transport most of the heat in these alloys. Such a thermal conductivity reduction would lead to substantial improvements in the figure-of-merit and efficiency of thermoelectric materials used in power generation applications. This paper reports on the results of adding 40 A particles to SiGe by using a spark erosion process. Thermal conductivity reductions consistent with the transport models have been achieved, however, the improvement in figure-of-merit has not been as large as predicted. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Scoville, N.; Bajgar, C.; Rolfe, J. [ThermoTrex Corporation, 74 West Street, Waltham, Massachusetts 02254 (United States); Fleurial, J.; Vandersande, J. [Jet Propulsion Laboratory, 2800 Oak Grove Drive, Pasadena, California 91109 (United States)

1994-08-10

97

Co Alloy SiO2 Granular-Type Longitudinal Media for Sputtered Tape Applications  

Microsoft Academic Search

We investigated bias-sputtered Co alloy-films (CoCrPt- and CoPt-) for high density magnetic tape media. We used bias sputtering to achieve desirable properties (good in-plane orientation and low noise) in these media. The CoCrPt-sputtered tape media showed a flat frequency response with a of 160 kfci and a corresponding signal-to-noise ratio of 21 dB. The overwrite performance was better than 40

Hwan-Soo Lee; Takanori Sato; Hiroaki Ono; Lin Wang; James A. Bain; David E. Laughlin

2007-01-01

98

High temperature deformation behavior of ? + ?-type biomedical titanium alloy Ti–6Al–7Nb  

Microsoft Academic Search

Isothermal hot compression tests were carried out in the temperature range 750–900°C and strain rate range 0.001–10s?1 for implant biomedical Ti–6Al–7Nb alloy to obtain the hot deformation behavior. Hot tensile tests were conducted to examine the hot ductility. The stress–strain curves in hot compression tests behave the characteristics of flow softening. According to the kinetic rate equation, the apparent activation

W. F. Cui; Z. Jin; A. H. Guo; L. Zhou

2009-01-01

99

Crevice Repassivation Potential of Alloy 22 in High-Nitrate Dust Deliquescence Type Environments  

SciTech Connect

The nitrate ion (NO{sub 3}{sup -}) is an inhibitor for crevice corrosion of Alloy 22 (N06022) in chloride (Cl{sup -}) aqueous solutions. Naturally formed electrolytes may contain both chloride and nitrate ions. The higher the ratio R = [NO{sub 3}{sup -}]/[Cl{sup -}] in the solution the stronger the inhibition of crevice corrosion. Atmospheric desert dust contains both chloride and nitrate salts, generally based on sodium (Na{sup +}) and potassium (K{sup +}). Some of these salts may deliquescence at relatively low humidity at temperatures on the order of 150 C and higher. The resulting deliquescent brines are highly concentrated and especially rich in nitrate. Electrochemical tests have been performed to explore the anodic behavior of Alloy 22 in high chloride high nitrate electrolytes at temperatures as high as 150 C at ambient atmospheres. Naturally formed brines at temperatures higher than 120 C do not induce crevice corrosion in Alloy 22 because they contain high levels of nitrate. The inhibitive effect of nitrate on crevice corrosion is still active for temperatures higher than 100 C.

Lian, T; Gdowski, G E; Hailey, P D; Rebak, R B

2007-02-08

100

[Influence of types and surface treatment of dental alloy and film thickness of cements on bond strength of dental luting cements].  

PubMed

The goal of this study was to test the influence of the type and oxidation treatment of dental casting alloys on the tensile bond strength of luting cements. Also, the influence of film thickness of luting cements on the tensile bond strength of different dental casting alloys was examined. Four different luting cements (zinc phosphate, polycarboxylate, glass ionomer and adhesive resin cements) and four different dental casting alloys (Au-Ag-Cu, Ag-Pd, hardened Ag-Pd and Ni-Cr alloys) were used. Cylindrical alloy rods for the tensile bond strength test were casted, and then, top surfaces of the rods were cemented with each luting cement to the bottom surfaces of other rods, using the film thickness adjustment apparatus. The film thickness of luting cement was adjusted to 20, 30, 50, 75 or 100 microns. The tensile bond strengths of each cement to different casting alloys at each film thickness were measured one day after the rods had been cemented. The tensile bond strength of the zinc phosphate cement could not be determined in this study due to the separation of the alloy rods cemented with the zinc phosphate cement in water before the tensile test. The tensile bond strength to the adhesive resin cement to any alloy showed the greatest strength; however, that of the glass ionomer cement to any alloy was the lowest strength among the cements examined. The Ni-Cr alloy had the highest bond strength of any luting cement, compared to other alloys. The tensile bond strengths of luting cements significantly decreased with the increase in film thickness of cement layer. The adhesive resin cement had the greatest bond strength, and the glass ionomer cement was the lowest bond strength at any film thickness. The oxidation treatment significantly increased the bond strength of the adhesive resin cement to both Au-Ag-Cu and Ag-Pd alloys. The tensile bond strength of the adhesive resin cement was most dependent upon the film thickness of cement layer, and that of the polycarboxylate cement was least dependent upon the film thickness of cement layer among the cements examined. In addition, the oxidation treatment for precious alloys could be a factor contributing to the increase in the bond strength of the adhesive resin cement. PMID:2135542

Hibino, Y

1990-11-01

101

Hydrogen embrittlement of ultra-pure alloys of the inconel 600 type: Influence of the additions of elements (C, P, Sn, Sb)  

NASA Astrophysics Data System (ADS)

The mechanical behavior of very high purity nickel base alloys of the Inconel 600 type that were simultaneously charged with hydrogen and deformed in tension was investigated. Experimental results show that this procedure decreases markedly the fracture strain of the pure 76 pct Ni-16 pct Cr-8 pct Fe alloy; cracks are observed after two to four pct elongation, and the fracture is completely intercrystalline. Hydrogen embrittlement appears as an intrinsic property of the Ni-Cr-Fe system in the sense that the grain boundary cohesion decreases when the purity of the alloy increases. The presence of carbon or phosphorus in the alloys increases grain boundary cohesion. The addition of metallic elements such as antimony or tin has relatively little effect on intergranular embrittlement.

Cornet, M.; Bertrand, C.; Belo, M. Da Cunha

1982-01-01

102

Environmental factors in the stress corrosion cracking of type 316L stainless steel and alloy 825 in chloride solutions  

SciTech Connect

This paper describes the experimental studies conducted to date to investigate the stress corrosion cracking (SCC) of candidate container materials for the proposed high-level nuclear waste repository at Yucca Mountain, Nevada. The effects of environmental variables, such as chloride concentration, the addition of thiosulfate, and temperature on the SCC susceptibility of type 316L, stainless steel (SS) and alloy 825 (Ni-29% Fe-22% Cr-3.0% Mo-2.0% Cu-1.0% Ti) were studied at temperatures from 95 C to 120 C. Results of slow strain rate tests (SSRT) at various potentials were compared to those obtained under constant deflection conditions using U-bend specimens to determine the existence of a critical potential for SCC. While not conclusive, results generated thus far have been consistent with the hypothesis that the repassivation potential for localized corrosion is also the critical potential for SCC in these environments. It was confirmed that alloy 825 was significantly more resistant to SCC than type 316L SS, using both constant deflection tests and SSRT, over a wide range of Cl{sup {minus}} concentrations. In contrast deflection tests, type 316 L SS exhibited cracks above the vapor-solution interface in solutions containing 1,000 ppm Cl{sup {minus}}, indicating that the local environment created as a liquid film on the specimen surface could be more detrimental than the bulk environment. SCC of type 316L SS was observed in SSRT only at Cl{sup {minus}} concentrations > {approximately}6 molal, whereas U-bend tests indicated cracking in 0.03 molal Cl{sup {minus}} solutions.

Cragnolino, G.; Dunn, D.S.; Sridhar, N. [Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses

1996-03-01

103

Thermoelectric properties of fine-grained FeVSb half-Heusler alloys tuned to p-type by substituting vanadium with titanium  

NASA Astrophysics Data System (ADS)

Fine-grained Ti-doped FeVSb half-Heusler alloys were synthesized by combining mechanical alloying and spark plasma sintering and their thermoelectric properties were investigated with an emphasis on the influences of Ti doping and phase purity. It was found that substituting V with Ti can change the electrical transport behavior from n-type to p-type due to one less valence electron of Ti than V, and the sample with nominal composition FeV0.8Ti0.4Sb exhibits the largest Seebeck coefficient and the maximum power factor. By optimizing the sintering temperature and applying annealing treatment, the power factor is significantly improved and the thermal conductivity is reduced simultaneously, resulting in a ZT value of 0.43 at 500 °C, which is relatively high as for p-type half-Heusler alloys containing earth-abundant elements.

Zou, Minmin; Li, Jing-Feng; Kita, Takuji

2013-02-01

104

Improved Thermoelectric Performance of p Type Bismuth Antimony Telluride Bulk Alloys Prepared by Hot Forging  

Microsoft Academic Search

The thermoelectric (TE) performance of Bi0.5Sb1.5Te3 polycrystalline alloys has been improved by a simple hot-forging process. No obvious texture was observed in the x-ray diffraction\\u000a (XRD) patterns of the hot-forged samples. Transport property measurements indicated that the hot-forged samples possessed\\u000a extremely low thermal conductivities. A maximum ZT value of ?1.1 at room temperature was obtained for the sample forged under

J. J. Shen; Z. Z. Yin; S. H. Yang; C. Yu; T. J. Zhu; X. B. Zhao

2011-01-01

105

Nanocomposite Nd-rich Nd-Fe-B alloys: Approaching ideal Stoner-Wohlfarth type behavior  

NASA Astrophysics Data System (ADS)

Starting from rapidly quenched Nd?Fe13.1B(2.05<=?<=147.6) alloys and by appropriate annealing, the microstructure was tailored from strongly interacting Nd2Fe14B grains to magnetically isolated single domain Nd2Fe14B grains embedded in a nonmagnetic Nd-rich matrix (?-Nd and ?-Nd). This change in microstructure was found to have a large effect on coercivity, i.e., coercivity, ?0Hc, increases with an increase of the Nd concentration from 1.25 T in Nd2.05Fe13.1B to 2.75 T in Nd147.6Fe13.1B at 290 K. Using transmission electron microscopy, the Nd2Fe14B grains in Nd147.6Fe13.1B were confirmed to be randomly oriented platelets with the c axis normal to the plate and an average size of 100×40×25 nm. For these randomly oriented, noninteracting, single domain Nd2Fe14B grains, the coercivity was calculated using a Stoner-Wohlfarth model which included the shape anisotropy of the grains. The observed coercivity of Nd2Fe14B in such nanocomposite Nd147.6Fe13.1B alloys is ~83% of its theoretical value.

Girt, Er.; Krishnan, Kannan M.; Thomas, G.; Altounian, Z.

2000-03-01

106

Electrochemical corrosion and modeling studies of types 7075 and 2219 aluminum alloys in a nitric acid + ferric sulfate deoxidizer solution  

NASA Astrophysics Data System (ADS)

The corrosion behavior of types 7075-T73 and 2219-T852 high strength aluminum alloys have been investigated in a HNO3 + Fe2(SO 4)3 solution. The materials are characterized in the time domain using the electrochemical noise resistance parameter (Rn) and in the frequency-domain using the spectral noise impedance parameter ( Rsn). The Rsn parameter is derived from an equivalent electrical circuit model that represents the corrosion test cell schematic used in the present study. These calculated parameters are correlated to each other, and to corresponding scanning electron microscopy (SEM) examinations of the corroded surfaces. In addition, energy dispersive spectroscopy (EDS) spectra are used in conjunction with SEM exams for particle mapping and identification. These constituent particles are characterized with respect to their size and composition and their effect on the localized corrosion mechanisms taking place. Pitting mechanisms are identified as 'circumferential' where the particles appeared noble with respect to the aluminum matrix and by 'selective dissolution' where they are anodic to the aluminum matrix. The electrochemical data are found to be in good agreement with the surface examinations. Specifically, the electrochemical parameters Rn and Rsn were consistent in predicting the corrosion resistance of 7075-T73 to be lower than for the 2219-T852 alloy. Other characteristic features used in understanding the corrosion mechanisms include the open circuit potential (OCP) and coupling-current time records.

Savas, Terence P.

107

Platinum-group minerals from placers related to the Nizhni Tagil (Middle Urals, Russia) Uralian-Alaskan-type ultramafic complex: ore-mineralogy and study of silicate inclusions in (Pt, Fe) alloys  

Microsoft Academic Search

Summary  The study of platinum-group minerals (PGM) concentrates from the Nizhni Tagil placers related to the Soloviev Mountain (Gora\\u000a Solovieva) Uralian-Alaskan-type intrusion revealed a predominance of (Pt, Fe) alloys over Ir-, and Os-bearing alloys. (Pt,\\u000a Fe) alloys (“isoferroplatinum-type”) are interstitial with respect to chromite and show important variations in their chemical\\u000a compositions, which are, however, falling within the experimentally determined stability

Z. Johan

2006-01-01

108

Correlation Between Two Types of Surface Stress Mitigation and the Resistance to Corrosion of Alloy 22  

SciTech Connect

When metallic plates are welded, residual tensile stresses may develop in the vicinity of the weld seam. Processes such as Low Plasticity Burnishing (LPB) and Laser Shock Peening (LSP) could be applied locally to eliminate the residual stresses produced by welding. In this study, Alloy 22 (N06022) plates were welded and then the above-mentioned surface treatments were applied to eliminate the residual tensile stresses. The aim of the current study was to compare the corrosion behavior of as-welded (ASW) plates with the corrosion behavior of plates with stress mitigated surfaces. Immersion and electrochemical tests were performed. Results show that the corrosion resistance of the mitigated plates was not affected by the surface treatments applied.

Yilmaz, A; Fix, D V; Estill, J C; Rebak, R B

2005-02-04

109

The characterization of shape memory effect for low elastic modulus biomedical {beta}-type titanium alloy  

SciTech Connect

This work investigates the textures of biomedical TiNbTaZr alloy rolled by 99% cold reduction ratios in thickness. The relationship between textures and superelasticity of the specimens treated at 873 K and 1223 K for 1.2 ks is studied. The microstructure of tensile specimen is investigated by transmission electron microscopy. Textures of cold-rolled and heat-treated specimens are studied. During unloading, the anisotropy of superelastic strain and pure elastic strain in the heat-treated specimens is observed. Superelastic strain along rolling direction and transverse direction is larger than those along 45 deg. from rolling direction while pure elastic strain shows the highest value along 45 deg. from rolling direction in the specimen treated at 873 K. For the specimen treated at 1223 K, higher pure elastic strain is obtained along rolling direction. The maximum recovered strain around 2.11% is obtained along rolling direction.

Wang Liqiang [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Lu Weijie, E-mail: luweijie@sjtu.edu.cn [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Qin Jining; Zhang Fan; Zhang Di [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China)

2010-05-15

110

Highly reflective Ag-Cu alloy-based ohmic contact on p-type GaN using Ru overlayer.  

PubMed

We report on a metallization scheme of high reflectance, low resistance, and smooth surface morphology ohmic contact on p-type GaN. Ag-Cu alloy/Ru contact showed low contact resistivity as low as 6.2 x 10(-6) Ohms cm(2) and high reflectance of 91% at 460 nm after annealing at 400 degrees C in air ambient. The oxidation annealing promoted the out-diffusion of Ga atoms to dissolve in an Ag-Cu layer with the formation of an Ag-Ga solid solution, lowering the contact resistivity. The Ru overlayer acts as a diffusion barrier for excessive oxygen incorporation during oxidation annealing, resulting in high reflectance, good thermal stability, and smooth surface quality of the contact. PMID:19079488

Son, Jun Ho; Jung, Gwan Ho; Lee, Jong-Lam

2008-12-15

111

Microstructure and thermoelectric properties of bulk and porous n-type silicon-germanium alloy prepared by HUP  

NASA Astrophysics Data System (ADS)

The optimization of powders preparation and consolidation process leads to the achievement of a high thermoelectric figure of merit (ZT=1.25 at 800°C) in an n-type silicon-germanium (SiGe) alloy hot pressed at low heating rate. It has been experimentally observed that HUP compacting conditions can preserve nanostructuring. We also investigated the effect of porosity on the thermoelectric properties. Porous samples have enhanced Seebeck coefficients and low thermal conductivity. However, the figure of merit of the bulk specimen remains better than the porous samples due to a significant degradation of electrical conductivity. Working on grain boundaries engineering to enhance charge carriers mobility seems to be a promising way in addition to limiting nanograin growth with a densification process control.

Kallel, A.; Roux, G.; Derycke, T.; Martin, C. L.; Marinova, M.; Cayron, C.

2012-06-01

112

Fabrication of a maxillary posterior fixed partial denture with a type 4 gold alloy and a dual-polymerizing indirect composite.  

PubMed

The aim of the present study was to design and fabricate a maxillary posterior fixed partial denture (FPD) made of a type 4 gold alloy and an indirect composite. Unlike the conventional framework design of a resin veneered restoration, cut-back was extended approximately 1/4 to 1/3 width in the occlusal table of the buccal cusp. Multiple retentive beads 150-200 mum in diameter were placed on the metal surface to be veneered. The gold alloy was cast in a cristobalite mold using a centrifugal casting machine. The cut surface with the retentive beads was air-abraded with alumina, and a priming agent (Alloy Primer) that contained triazine dithione monomer (VTD) was applied. A tooth-colored veneer was then fabricated with a highly loaded light- and heat-cured composite material (Estenia). This design and procedure can be applied as a standardized laboratory technique for fabrication of maxillary posterior restorations and FPDs. PMID:18403895

Matsumura, Hideo; Mori, Shuichi; Tanoue, Naomi

2008-03-01

113

Determination of thermal conductivities of Sn-Zn lead-free solder alloys with radial heat flow and Bridgman-type apparatus  

NASA Astrophysics Data System (ADS)

The variations of thermal conductivities of solid phases versus temperature for pure Sn, pure Zn and Sn-9 wt.% Zn, Sn-14 wt.% Zn, Sn-50 wt.% Zn, Sn-80 wt.% Zn binary alloys were measured with a radial heat flow apparatus. The thermal conductivity ratios of liquid phase to solid phase for the pure Sn, pure Zn and eutectic Sn-9 wt.% Zn alloy at their melting temperature are found with a Bridgman-type directional solidification apparatus. Thus, the thermal conductivities of liquid phases for pure Sn, pure Zn and eutectic Sn-9 wt.% Zn binary alloy at their melting temperature were evaluated by using the values of solid phase thermal conductivities and the thermal conductivity ratios of liquid phase to solid phase.

Meydaneri, Fatma; Saatçi, Buket; Gündüz, Mehmet; Özdemir, Mehmet

2012-08-01

114

Evidence for graphitic-type bonding in glow discharge hydrogenated amorphous silicon carbon alloys  

Microsoft Academic Search

Amorphous silicon carbon (a-SiC:H) films have been deposited by the glow discharge technique using SiH4 and CH4 gas mixtures. At high discharge powers and low deposition chamber pressures, evidence for graphitic-type bonding in C-deficient a-SiC:H is found and correlations are made between the appearance of this bonding with significant changes in the electronic and structural properties. This graphitic-type bonding can

A. H. Mahan; B. von Roedern; D. L. Williamson; A. Madan

1985-01-01

115

Shockley-Type Surface States on the (111) and (110) Surfaces of Cu-BASED Alloys with Noble and Transition Metal Impurities  

NASA Astrophysics Data System (ADS)

We have investigated Shockley-type surface states (SSS's) on ideal semi-infinite surfaces of randomly disordered alloys, Cu70Ni30, Cu80Ni20, Cu90Ni10, Cu85Pd15, Cu95Pd5, and Cu90Au10 using a Green's function approach. In particular, the binding energies and disorder induced smearings of the bar ? -centered SSS's on the (111) surfaces and the bar Y-centered SSS's on the (110) surfaces of these alloys are presented. Our theoretical predictions are in good accord with the available angle-resolved photoemission measurements, although the experimental results in this regard for well-characterized alloy surfaces appear to be limited to the (111) surfaces of CuPd and CuAu solid solutions. The binding energy of the SSS's is found to decrease roughly linearly with decreasing e/a ratio, but significant deviations from such a rigid-band behavior are noted for various impurities. The SSS's investigated in this article lie in the L2' -L1u gap in the bulk alloy electronic spectrum, and their character (changes in binding energy on alloying, and disorder induced smearing) is correlated with that of the L2? bulk level.

Serageldin, A. Y.; Prasad, R.; Bansil, A.

116

Comparison of different pressing techniques for the preparation of n-type silicon-germanium thermoelectric alloys  

SciTech Connect

Improvements to state-of-the-art Si{sub 80}Ge{sub 20} thermoelectric alloys have been observed in laboratory-scale samples by the powder metallurgy techniques of mechanical alloying and hot pressing. Incorporating these improvements in large scale compacts for the production of thermoelectric generator elements is the next step in achieving higher efficiency RTGs. This paper discusses consolidation of large quantities of mechanically alloyed powders into production size compacts. Differences in thermoelectric properties are noted between the compacts prepared by the standard technique of hot uniaxial pressing and hot isostatic pressing. Most significant is the difference in carrier concentration between the alloys prepared by the two consolidation techniques.

Harringa, J.L.; Cook, B.A.

1996-06-01

117

Determination of vacancy concentration and defect structure in the B2 type NiAl {beta}-phase alloys  

SciTech Connect

The B2 type NiAl {beta}-phase alloys exhibit a complex type of point defects as the constitutional defect in off-stoichiometric composition regions. This was first established by Bradley and Taylor from the measurements of density and lattice constant. Their proposed defect structure model, the BT model, is that, on the Ni-rich side of stoichiometry the Ni antistructure defects, the Ni-ASD, resulting from substitution of the excess of Ni atoms on the Al-site which is the lattice site assigned to Al atoms, are formed, whereas instead of formation of the Al-ASD, the vacancies on the Ni-site, the Ni-vacancies, are created on the Al-rich side. In this paper which is concerned with the defect structure appearing in the NiAl {beta}-phase, the authors report the results of density measurements by the use of powdered samples instead of bulk material and the results of X-ray analyses performed for these samples based on their own density data.

Kogachi, M.; Tanahashi, T. [Univ. of Osaka Prefecture, Sakai (Japan); Shirai, Y.; Yamaguchi, M. [Kyoto Univ. (Japan). Dept. of Materials Science and Engineering

1996-01-15

118

Fabrication of L1{sub 1}-type (Co-Ni)-Pt ordered alloy films by sputter deposition  

SciTech Connect

L1{sub 1}-type (Co-Ni)-Pt ordered alloy perpendicular films were successfully fabricated on MgO(111) single crystal substrates using ultrahigh vacuum sputter film deposition; the addition of Ni to Co-Pt was effective to reduce saturation magnetization, M{sub s}, maintaining a large K{sub u} of the order of 10{sup 7} erg/cm{sup 3}. L1{sub 1}-type ordered structures, with the <111> direction (easy axis of magnetization) perpendicular to the films, were successfully fabricated at a substrate temperature of 360 deg. C in a wide composition range with Co content less than 60 at. %. The order parameter, S, was almost a constant of about 0.5 in the stoichiometric composition of (Co{sub 1-X}Ni{sub X}){sub 50}Pt{sub 50}, independent of Ni content, X. L1{sub 1}-type Co-Ni-Pt perpendicular films having a large K{sub u} of (1-2.5)x10{sup 7} erg/cm{sup 3} and a relatively low M{sub s} of 400-700 emu/cm{sup 3} were successfully fabricated in the composition range of 10-35 at. % Co, 20-55 at. % Ni, and bal. Pt. K{sub u} should increase further with enhanced ordering. Experimental results demonstrated the potential of these Co-Ni-Pt ordered films for use in data storage applications due to very high K{sub u} potential comparable to L1{sub 0}-type Fe{sub 50}Pt{sub 50} films, relatively low M{sub s}, the relatively low fabrication temperature, and good controllability of the grain orientation.

Sato, H. [Institute of Multidisciplinary Research for Advanced Material, Tohoku University, Sendai 980-8577 (Japan); Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Shimatsu, T.; Aoi, H. [Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Kataoka, H. [Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Fuji Electric Device Technology, Co., Ltd., Matsumoto 390-0821 (Japan); Okamoto, S.; Kitakami, O. [Institute of Multidisciplinary Research for Advanced Material, Tohoku University, Sendai 980-8577 (Japan)

2009-04-01

119

Development Program for Improving Foundry and Repair Welding Techniques for ZE41-type Magnesium Alloy Castings.  

National Technical Information Service (NTIS)

This report describes a development program for improved foundry and repair welding techniques for large complex ZE41-type magnesium castings, such as currently specified by the designers of next generation of army aircraft (e.g. the AAH, UTTAS, etc.). Th...

J. Desai

1976-01-01

120

Optimization of Cr content of metastable ?-type Ti-Cr alloys with changeable Young's modulus for spinal fixation applications.  

PubMed

Metallic implant rods used in spinal fixtures should have a Young's modulus that is sufficiently low to prevent stress shielding for the patient and sufficiently high to suppress springback for the surgeon. Therefore, we propose a new concept: novel biomedical titanium alloys with a changeable Young's modulus via deformation-induced ? phase transformation. In this study, the Cr content in the range of 10-14 mass% was optimized to produce deformation-induced ? phase transformation, resulting in a large increase in the Young's modulus of binary Ti-Cr alloys. The springback and cytotoxicity of the optimized alloys were also examined. Ti-(10-12)Cr alloys exhibit an increase in Young's modulus owing to deformation-induced ? phase transformation. In this case, such deformation-induced ? phase transformation occurs along with {332}(?) mechanical twinning, resulting in the maintenance of acceptable ductility with relatively high strength. Among the examined alloys, the lowest Young's modulus and largest increase in Young's modulus are obtained from the Ti-12Cr alloy. This alloy exhibits smaller springback than and comparable cytocompatibility to the biomedical Ti alloy Ti-29Nb-13Ta-4.6Zr. PMID:22342893

Zhao, Xingfeng; Niinomi, Mitsuo; Nakai, Masaaki; Hieda, Junko; Ishimoto, Takuya; Nakano, Takayoshi

2012-02-15

121

Resistance of Welded Joints in High Temperature Hastelloy N-Type Nickel Alloy to Hot Crack Formation (Abstract Only),  

National Technical Information Service (NTIS)

The topography and morphology of hot cracks in welded joints of a high temperature nickel alloy in the nickel chromium molybdenum system was refined. The crack resistance of welded joints in an experimental Hastelloy N alloy was studied. Butt joints of ri...

K. A. Yushchenko V. N. Lipodayev M. V. Belchuk G. N. Gordan O. V. Novichkova

1987-01-01

122

DEVELOPMENT OF DIFFUSION-TYPE BONDING TECHNIQUES FOR BERYLCO-25 ALLOY  

Microsoft Academic Search

Bond tensile strengths in excess of 90,000 psi in joining precipitation-; hardened beryllium -copper have been obtained by diffusion techniques. Ordinary ; brazing techniques for beryllium--copper have resulted in an average of 40,000-; psi tensile strength in the bond. Bonds with tensile strengths averaging 108,400 ; psi have been developed using high-vacuum, diffusion-type bonding techniques. ; Hardnesses averaging 38 Rockwell

G. R. Baxter; J. A. Hoffman; R. C. Bertossa; B. R. Cottrell

1961-01-01

123

A new type of FCT martensite phase in single-crystalline Fe 3Pt Invar alloy  

Microsoft Academic Search

Martensitic transformation in a highly ordered Fe3Pt has been investigated by magnetization and X-ray diffraction measurements. We confirmed that a new type of face-centered tetragonal (FCT) martensite phase appears below 60K in Fe3Pt with a degree of order S=0.88. The tetragonality c\\/a gradually increases with decreasing temperature, and is approximately 1.005 at 10K. This is in contrast to the tetragonality

Masataka Yamamoto; Sayaka Sekida; Takashi Fukuda; Tomoyuki Kakeshita; Kohki Takahashi; Keiichi Koyama; Hiroyuki Nojiri

2011-01-01

124

Effect of processing parameters on the earing and mechanical properties of strip cast type 3004 Al alloy  

SciTech Connect

Electrical resistivity, superficial hardness, tensile testing, and quantitative metallography techniques were used in this study. The strip cast type 3004 aluminum alloy received sixteen different thermomechanical treatments before cups were drawn. The top edges of the drawn cups were not flat. Rather there were high points or ears with valleys between them. The homogenization temperature varied from 510 to 621 C at 24 h. Some samples received an additional 426 C/24 h homogenization anneal. Most specimens were rolled along the longitudinal direction of the as-cast material, and some were rolled in the transverse direction. Most samples were recrystallized at 454 C for 24 h in addition to the homogenization treatment. Some were recrystallized for 168 h. All samples were subsequently rolled to 0.33 mm for cup drawing and percent earing determination. The percent earing results of some samples were less than 1.5%, but the mechanical strength was also lowered. The high-temperature recrystallization anneal of 454 C was the controlling factor in determining the earing and mechanical strength of the final rolled sheet.

Es-Said, O.S.; Zeihen, A.; Ruprich, M.; Quattrocchi, J.; Thomas, M.; Shin, K.H.; O`Brien, M.; Johansen, D.; Tijoe, W.H.; Ruhl, D. [Loyola Marymount Univ., Los Angeles, CA (United States). Mechanical Engineering Dept.

1995-06-01

125

Fast simulation of phase-change processes in chalcogenide alloys using a Gillespie-type cellular automata approach  

NASA Astrophysics Data System (ADS)

A stochastic cellular automata simulator capable of spatiotemporal modeling of the crystallization and amorphization behavior of phase-change materials during the complex annealing cycles used in optical and electrical memory applications is presented. This is based on consideration of bulk and surface energies to generate rates of growth and decay of crystallites built up from ``monomers'' that may themselves be quite complex molecules. The approach uses a stochastic Gillespie-type time-stepping algorithm to deal with events that may occur on a very wide range of time scales. The simulations are performed at molecular length scale and using an approximation of local free energy changes that depend only on immediate neighbors. The approach is potentially capable of spanning the length scales between ab initio atomistic modeling methods, such as density functional theory, and bulk-scale methods, such the Johnshon-Mehl-Avrami-Kolmogorov formalism. As an example the model is used to predict the crystallization behavior in the chalcogenide Ge2Sb2Te5 alloy commonly used in phase-change memory devices. The simulations include annealing cycles with nontrivial spatial and temporal variations in temperature, with good agreement to experimental incubation times at low temperatures while modeling nontrivial crystal size distributions and melting dynamics at higher temperatures.

Ashwin, Peter; Patnaik, B. S. V.; Wright, C. David

2008-10-01

126

Development of One-Body Type Water and Air-Cooling Fixed Masks Made of Forged 0.2% Beryllium Copper Alloy  

Microsoft Academic Search

One-body type water- and air-cooling fixed masks made of forged 0.2% beryllium copper alloy have been developed, and successfully applied for the front end of a new undulator beamline, BL-13A, at the Photon Factory in Tsukuba, Japan. Advantages of the masks are a simple structure, no welding, low cost, high duration, and an extremely low out-gassing rate. Forged 0.2% beryllium

Kazuhiko Mase; Takashi Kikuchi; Hirokazu Tanaka; Akio Toyoshima; Fumio Watanabe

2010-01-01

127

Improvement in Fatigue Strength of Biomedical beta-type Ti-Nb-Ta-Zr Alloy While Maintaining Low Young's Modulus Through Optimizing omega-Phase Precipitation  

Microsoft Academic Search

The improvement in fatigue strength, with maintenance of a low Young's modulus, in a biomedical beta-type titanium alloy, Ti-29Nb-13Ta-4.6Zr (TNTZ), by thermomechanical treatment was investigated. A short aging time at an omega-phase-forming temperature combined with severe cold rolling was employed. A fine omega phase is observed in TNTZ subjected to this thermomechanical treatment. Because the rolling texture of beta phase

Masaaki Nakai; Mitsuo Niinomi; Takahiro Oneda

2011-01-01

128

A novel catalyst with plate-type anodic alumina supports, Ni\\/NiAl 2O 4\\/?-Al 2O 3\\/alloy, for steam reforming of methane  

Microsoft Academic Search

A series of plate-type metal-monolithic anodic alumina supported nickel catalysts were employed to investigate their reactivity in the steam reforming of methane reactions. After H2 reduction, a fresh 4.7wt% Ni\\/?-Al2O3\\/alloy catalyst provided only a short-term activity, and then deactivated quickly. By the temperature programmed reaction technologies, the oxidation of surface sintered metallic Ni particles in the SRM test was suggested

Lu Zhou; Yu Guo; Qi Zhang; Masayuki Yagi; Jun Hatakeyama; Huabo Li; Jian Chen; Makoto Sakurai; Hideo Kameyama

2008-01-01

129

Effect of CuO addition on electrochemical properties of AB 3-type alloy electrodes for nickel\\/metal hydride batteries  

Microsoft Academic Search

In order to improve overall electrochemical properties of AB3-type hydrogen storage alloy electrodes, especially the cycling stability, CuO was added to the electrode. Electrochemical properties of the electrodes with and without additives were studied. Cyclic voltammetry and SEM results show that CuO is reduced to Cu during the charging process and the fine Cu particles deposit at surface of the

Yuan Li; Shumin Han; Xilin Zhu; Huiling Ding

2010-01-01

130

Structural and magnetic properties of Fe-Cr-Al alloys with DO3-type structure  

NASA Astrophysics Data System (ADS)

X-ray, neutron, magnetization and Mössbauer studies in the temperature range 10-300 K are reported forFe3-xCrxAl system with x < 0.6. The experiments indicate that a single phase having the DO3-type structure is maintained in the range of Cr concentration studied. It was found that Cr atoms occupy preferentially B-sites and the lattice constant decreases with increasing concentration of chromium. The magnetic moment of chromium is small and diminishes the value of neighbouring iron atoms by about 0.1 ?B per Cr atom. The magnetic moments of iron at (A, C) and B sites were estimated to be 1.54 (22), 2.58 (22), 1.51 (27) and 2.32 (14) ?B for T = 10 and 300 K, respectively. The magnetic moment of iron decreases by 0.37(10) and 0.26(6) ?B at 10 K and T = 300 K, respectively, if one aluminium atom is found as a nearest neighbour of iron.

Satu?a, D.; Dobrzy?ski, L.; Waliszewski, J.; Szyma?ski, K.; Re?ko, K.; Malinowski, A.; Brückel, Th.; Schärpf, O.; Blinowski, K.

1997-05-01

131

Microstructural characterization of a Zr-Ti-Ni-Mn-V-Cr based AB{sub 2}-type battery alloy  

SciTech Connect

Transmission Electron Microscopy (TEM), combined with X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) was employed to investigate a proprietary and multicomponent AB{sub 2} type Nickel-Metal Hydride (Ni-MH) battery alloy. This material was prepared by High Pressure Gas Atomization (HPGA) and examined in both the as-atomized and heat treated condition. TEM examination showed a heavily faulted dendritic growth structure in as-atomized powder. Selected Area Diffraction (SAD) showed that this region consisted of both a cubic C15 structure with lattice constant a=7.03 and a hexagonal C14 structure with lattice parameter a=4.97 {angstrom}, c=8.11 {angstrom}. The Orientation Relationship (OR) between the C14 and C15 structures was determined to be (111)[1{bar 1}0]{sub C15}//(0001)[11{bar 2}0]{sub C14}. An interdendritic phase possessing the C14 structure was also seen. There was also a very fine grain region consisting of the C14 structure. Upon heat treatment, the faulted structure became more defined and appeared as intercalation layers within the grains. Spherical particles rich in Zr and Ni appeared scattered at the grain boundaries instead of the C14 interdendritic phase. The polycrystalline region also changed to a mixture of C14 and C15 structures. These results as well as phase stability of the C15 and C14 structures based on a consideration of atomic size factor and the average electron concentration are discussed.

Shi, Zhan

1999-01-01

132

Identification of dominant recombination mechanisms in narrow-bandgap InAs/InAsSb type-II superlattices and InAsSb alloys  

NASA Astrophysics Data System (ADS)

Minority carrier lifetimes in doped and undoped mid-wave infrared InAs/InAsSb type-II superlattices (T2SLs) and InAsSb alloys were measured from 77-300 K. The lifetimes were analyzed using Shockley-Read-Hall (SRH), radiative, and Auger recombination, allowing the contributions of the various recombination mechanisms to be distinguished and the dominant mechanisms identified. For the T2SLs, SRH recombination is the dominant mechanism. Defect levels with energies of 130 meV and 70 meV are determined for the undoped and doped T2SLs, respectively. The alloy lifetimes are limited by radiative and Auger recombination through the entire temperature range, with SRH not making a significant contribution.

Olson, B. V.; Shaner, E. A.; Kim, J. K.; Klem, J. F.; Hawkins, S. D.; Flatté, M. E.; Boggess, T. F.

2013-07-01

133

Amorphous metal alloy  

DOEpatents

Amorphous metal alloys of the iron-chromium and nickel-chromium type have excellent corrosion resistance and high temperature stability and are suitable for use as a protective coating on less corrosion resistant substrates. The alloys are stabilized in the amorphous state by one or more elements of titanium, zirconium, hafnium, niobium, tantalum, molybdenum, and tungsten. The alloy is preferably prepared by sputter deposition.

Wang, R.; Merz, M.D.

1980-04-09

134

Properties of the quaternary half-metal-type Heusler alloy Co2Mn1-xFexSi  

Microsoft Academic Search

This paper reports on the bulk properties of the quaternary Heusler alloy Co2Mn1-xFexSi with the Fe concentration x=0,1\\/2,1 . All samples, which were prepared by arc melting, exhibit L21 long-range order over the complete range of Fe concentration. The structural and magnetic properties of the Co2Mn1-xFexSi Heusler alloys were investigated by means of x-ray diffraction, high- and low-temperature magnetometry, Mössbauer

Benjamin Balke; Gerhard H. Fecher; Hem C. Kandpal; Claudia Felser; Keisuke Kobayashi; Eiji Ikenaga; Jung-Jin Kim; Shigenori Ueda

2006-01-01

135

Electrochemical Behavior of Gold Alloys.  

National Technical Information Service (NTIS)

Reactions resulting from polarization of five dental golds were studied. Test materials included an ADA certified type III alloy (oro B-2) three 'economy' alloys (midas, Neycast and Minigold) and a high-fusing alloy (Olympia). The solvent was dilute lacta...

E. F. Huget S. G. Vermilyea F. A. Modawar L. B. Simon

1979-01-01

136

Heat resistance of titanium alloys  

Microsoft Academic Search

1.We determined the variation of the heat resistance of titanium alloys as a function of the character of interaction between the alloyed components, the type of equilibrium diagram of the system, and the structure of the alloy.2.We obtained experimental data on the relationship between heat resistance and the composition for some titanium systems. These relationships could be used to create

I. I. Kornilov

1963-01-01

137

Heat Treatment Studies of Aluminum Alloy Type 7050 Forgings. Corroded-Specimen Fatigue Tests and SSC Propagation Tests.  

National Technical Information Service (NTIS)

The influence of previous corrosion on fatigue life was investigated. It was found that a slight corrosive attack could drastically reduce fatigue life. The damaging effect of corrosion was greater for the alloy AA 7050 than for AZ 74.61. It was establish...

H. P. Vanleeuwen L. Schra

1979-01-01

138

Occluded solution chemistry control and the role of alloy sulfur on the initiation of crevice corrosion in type 304ss  

Microsoft Academic Search

Because sulfide inclusions are recognized as the primary initiation sites for localized corrosion of austenitic stainless steels, the influence of alloy sulfur on the crevice solution chemistry and nature of the surface in the crevice at initiation were investigated. Through the coordinated use of occluded solution analysis, high resolution TEM?EDS, small-spot XPS, and electrochemical measurements, the dominance of the effects

C. S. Brossia; R. G. Kelly

1998-01-01

139

Thermoelectric device including an alloy of GeTe and AgSbTe as the P-type element  

DOEpatents

Improved alloys suitable for thermoelectric applications and having the general formula: (AgSbTe.sub.2).sub.1.sub.-x + (GeTe).sub.x wherein x has a value of about 0.80 and 0.85, have been found to possess unexpectedly high thermoelectric properties such as efficiency index, as well as other improved physical properties.

Skrabek, Emanuel Andrew (Baltimore, MD); Trimmer, Donald Smith (Timonium, MD)

1976-01-01

140

Novel Type of Aluminum-Alloy Jacketed ${\\\\rm Nb}_{3}{\\\\rm Sn}$ Superconductors Manufactured by Friction Stir Welding Technique  

Microsoft Academic Search

New process to compose a reacted ${\\\\rm Nb}_{3}{\\\\rm Sn}$ superconducting cable with aluminum-alloys has been developed by using friction stir welding (FSW) technique. The FSW joining process, which takes place in the solid phase below the melting point of the materials, has considerable advantages such as a high strength of welding zone and much lower distortion due to both small

Masahiro Sugimoto; Hitoshi Shimizu; Hirokazu Tsubouchi; Toshiya Okada; Toshirou Sakai; Toshio Ushiyama; Kazuya Takahata; Hitoshi Tamura; Toshiyuki Mito

2012-01-01

141

Ageing effects on ordering degree and morphology of 18R-type martensite in shape memory CuZnAl alloys  

SciTech Connect

Ageing effects in CuZnAl alloys have been investigated by X-ray diffraction and optical microscopy. The splittings observed in some selected diffraction peaks due to the monoclinicity of the martensite unit cell by basal plane distortion are referred to as monoclinic distortion. The spacing difference, {Delta}d, between some selected pairs of peaks may be used as a parameter to reflect the ordering degree in CuZnAl alloys, and the extent of {Delta}d difference and monoclinic distortion may depend on the type and degree of long range order or alloy composition. The variation of {Delta}d parameters for both as-quenched and post-quench {beta}-phase annealed specimens show a trend to decrease with holding duration at room temperature. This trend is closely related to the martensite stabilization, and this process is mainly due to the rearrangement of atoms in martensite lattice. Self-accommodating martensite morphology which has a diamond-like configuration has been observed in both as-quenched and post-quench heat-treated specimens. Parallel bands defined as lamellar martensite or twin-like morphologies have also been formed on the martensite plates, and interlamellar boundaries are not as straight as twin boundaries.

Kayali, N.; Oezgen, S.; Adiguezel, O. [Firat Univ., Elazig (Turkey)

1997-05-01

142

CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Enhancement in Thermoelectrical Power Factor of N-Type Si80Ge20 Alloys  

NASA Astrophysics Data System (ADS)

Influences of the carrier concentration and mobility of heavily doped n-type Si80 Ge20 alloys on the thermoelectrical power factor are investigated. The experimental results indicate that thermoelectrical power factors of 32-36?W cm-1 K-2 could be consistently achieved with carrier concentrations of 2.1-2.9 × 1020 cm-3 and carrier mobilities of 36-40 cm2 V-1 s-1. However, many samples with suitable carrier concentrations do not always have high mobilities and high power factors. Some possible explanations for this behaviour are discussed.

Xu, Ya-Dong; Xu, Gui-Ying; Liu, Yan-Hong; Ge, Chang-Chun

2008-07-01

143

Alloying of aluminum-beryllium alloys  

NASA Astrophysics Data System (ADS)

The existing phase diagrams of Al-Be- X alloys, where X is an alloying element, are analyzed. Element X is noted to poorly dissolve in both aluminum and beryllium. It is shown that the absence of intermetallic compounds in the Al-Be system affects the phase equilibria in an Al-Be- X system. Possible phase equilibria involving phases based on aluminum, beryllium, and intermetallic compounds are proposed, and the types of strengthening of Al-Be alloys by an addition of a third element are classified.

Molchanova, L. V.; Ilyushin, V. N.

2013-01-01

144

The effects of temperature and forming speed on the forming limit diagram for type 5083 aluminum–magnesium alloy sheet  

Microsoft Academic Search

The effects of forming speed and temperature on the forming limit diagram (FLD) were investigated experimentally for a fine-grain Al–Mg alloy (5083-O) sheet by performing stretch-forming tests at various forming speeds (0.2–200mmmin?1) at several temperatures from 293 to 573K. The forming limit strain increased drastically with decreasing speed for any strain paths at a high temperature ranging from 423 to

Tetsuo Naka; Gaku Torikai; Ryutaro Hino; Fusahito Yoshida

2001-01-01

145

De Haas-van Alphen Effect and Fermi Surface of Ordered Alloys of the beta Brass Type  

Microsoft Academic Search

The de Haas-van Alphen effect has been measured in the three ordered alloys beta'-CuZn, beta'-AgZn and beta'-PdIn (caesium chloride structure) by the pulsed field method. The results reveal a remarkable similarity between the Fermi surfaces of AgZn and PdIn; CuZn also fits into the general pattern, and there is in general good agreement with the results of band structure calculations

J.-P. Jan; W. B. Pearson; Y. Saito

1967-01-01

146

Enhanced thermoelectric figure-of-merit in p-type nanostructured bismuth antimony tellurium alloys made from elemental chunks.  

PubMed

By ball milling alloyed bulk crystalline ingots into nanopowders and hot pressing them, we had demonstrated high figure-of-merit in nanostructured bulk bismuth antimony telluride. In this study, we use the same ball milling and hot press technique, but start with elemental chunks of bismuth, antimony, and tellurium to avoid the ingot formation step. We show that a peak ZT of about 1.3 in the temperature range of 75 and 100 degrees C has been achieved. This process is more economical and environmentally friendly than starting from alloyed bulk crystalline ingots. The ZT improvement is caused mostly by the lower thermal conductivity, similar as the case using ingot. Transmission electron microscopy observations of the microstructures suggest that the lower thermal conductivity is mainly due to the increased phonon scattering from the increased grain boundaries of the nanograins, precipitates, nanodots, and defects. Our material also exhibits a ZT of 0.7 at 250 degrees C, similar to the value obtained when ingot was used. This study demonstrates that high ZT values can be achieved in nanostructured bulk materials with ball milling elemental chunks, suggesting that the approach can be applied to other materials that are hard to be made into ingot, in addition to its advantage of lower manufacturing cost. PMID:18624384

Ma, Yi; Hao, Qing; Poudel, Bed; Lan, Yucheng; Yu, Bo; Wang, Dezhi; Chen, Gang; Ren, Zhifeng

2008-07-12

147

The fractography of casting alloys  

Microsoft Academic Search

Several types of casting alloys were fractured using various loading modes (uniaxial tension, bending, impact, and torsion, and cyclic stressing), and the corresponding mechanical properties were determined. The unetched and etched fracture surfaces and the microstructures were examined using conventional techniques. The types of casting alloys that were the subjects f these investigations include gray iron, ductile iron, cast steel,

G POWELL

1994-01-01

148

Thermomechanical Treatment of Aluminum Alloys.  

National Technical Information Service (NTIS)

The effects of thermomechanical treatment (TMT) on the engineering properties of aluminum alloys are discussed. At present only one type of TMT seems commercially practicable. This is a T3XX type treatment for 2000 series alloy sheet. Of the other kinds o...

R. J. H. Wanhill G. F. J. A. Vangestel

1978-01-01

149

Disorder-activated Raman spectra of cubic rocksalt-type Li(1-x)/2Ga(1-x)/2MxO (M = Mg, Zn) alloys  

NASA Astrophysics Data System (ADS)

Disorder-activated phonon behaviors of the cubic rocksalt-type semiconductor alloy Li(1-x)/2Ga(1-x)/2MxO (M = Mg, Zn) prepared by high-pressure and high-temperature method has been studied by Raman scattering analysis. The LO Raman phonon in Li(1-x)/2Ga(1-x)/2MxO was found to exhibit a distinct two-mode behavior. The compositional dependence of Raman frequency, peak-width, and intensity has been discussed. A model associated with a composite mode of the Brillouin zone center and edge phonons combined with phonon dispersion curves determined by first-principle calculations were employed to explain the asymmetric broadening of the LO phonon mode. The broadening and asymmetric Raman line-shape in Li(1-x)/2Ga(1-x)/2MxO can be interpreted as a composite mode of the softening Brillouin zone center mode and the Brillouin zone edge mode.

Lei, Li; Ohfuji, Hiroaki; Irifune, Tetsuo; Qin, Jiaqian; Zhang, Xinyu; Shinmei, Toru

2012-08-01

150

High temperature low-cycle fatigue of friction welded joints - type 304-304 stainless steel and alloy 718-718 nickel base superalloy  

SciTech Connect

This paper assesses the high-temperature low-cycle fatigue of the Type 304 stainless steel and Alloy 718 superalloy friction-welded joints. Strain controlled low-cycle fatigue tests for 304-304 and 718-718 friction-welded specimens were carried out at 923 K in air to obtain the fatigue strength of the joints. These materials were selected as the cyclic hardening and softening materials, respectively. The 304-304 welded specimens showed inferior fatigue strength in comparison with the base metal while the 718-718 specimens exhibited fatigue strength equivalent to that of the base metal. The difference in the fatigue strength between the two materials is discussed from the viewpoint of the cyclic deformation behavior and strain reduction at weld interface.

Wakai, T. (Power Reactor and Nuclear Fuel Development Corp., Ibaraki (Japan). Oarai Engineering Center); Sakane, M.; Ohnami, M. (Ritsumeikan Univ., Kyoto (Japan). Dept. of Mechanical Engineering); Okita, K. (Hyogo Prefectural Inst. of Industrial Research, Miki (Japan). Technical Center for Machinery and Metals); Fukuchi, Y. (Hyogo Prefectural Inst. of Industrial Research, Kobe (Japan))

1993-01-01

151

Highly reflective MgAl alloy/Ag/Ru Ohmic contact with low contact resistivity on p-type GaN  

NASA Astrophysics Data System (ADS)

We report a metallization scheme of high-reflectance low-resistance Ohmic contact on p-type GaN. The high reflectance of 84% at 460 nm wavelength and the specific contact resistivity as low as 8.59×10-6 ? cm2 were obtained from MgAl-alloy(50 A?)/Ag(3000 A?)/Ru(500 A?) annealed at 450 °C in air. The formation of Ag-Ga solid solution due to the outdiffusion of Ga after annealing leads to an Ohmic behavior of the contact. Employing highly reflective MgAl as a contact layer and Ru as an overlayer that suppress the agglomeration and the oxidation of the Ag result in the high reflectance of the contact.

Lee, S.; Son, J. H.; Jung, G. H.; Kim, Y. G.; Kim, C. Y.; Yoon, Y. J.; Lee, J.-L.

2007-11-01

152

STRUCTURE AND PROPERTY COMPARISON OF ALLVAC® 718PLUS™ ALLOY AND WASPALOY FORGINGS  

Microsoft Academic Search

Alloy 718 has seen extensive use for many years due to its excellent mechanical properties, good processing characteristics, and relatively low cost. Numerous attempts have been made to develop a 718-type alloy with temperature capabilities higher than alloy 718. One of the most promising alloys to emerge from these efforts is Allvac® 718Plus™ Alloy. Interest in alloy 718Plus has grown

Ian Dempster; Wei-Di Cao; Richard Kennedy; Betsy Bond; Jose Aurrecoechea; Mark Lipschutz

153

Amorphization of transition metal Zr alloys by mechanical alloying  

Microsoft Academic Search

Amorphous alloy powders of the types NiZr, CoZr, FeZr, and CuZr are produced by mechanical alloying from crystalline elemental powders. The alloying and amorphization process is monitored by microstructural investigations, x-ray diffraction, and, where applicable, by magnetization measurements. The crystallization temperatures, determined by differential scanning calorimetry, are comparable to those measured for rapidly quenched and solid state reacted amorphous metals

E. Hellstern; L. Schultz

1986-01-01

154

Design and fabrication of a locomotive mechanism for capsule-type endoscopes using shape memory alloys (SMAs)  

Microsoft Academic Search

Endoscopes are medical devices to diagnose various kinds of diseases throughout the whole gastrointestinal tracks. Generally, they are divided into conventional push-type endoscopes and more recently developed wireless capsule-type endoscopes. The conventional endoscopes cannot reach the small intestines and generate pain and discomfort to patients due to the stiffness of their body. Such disadvantages do not exist in wireless capsule-type

Byungkyu Kim; Sunghak Lee; Jong Heong Park; Jong-Oh Park

2005-01-01

155

Effect of applied potential on changes in solution chemistry inside crevices on type 304L stainless steel and alloy 825  

SciTech Connect

Changes in pH, chloride (Cl) concentration, and potential inside a rectangular crevice of metal against polymethyl methacrylate (PMMA) were monitored using microelectrodes as a function of time and externally applied potential. The environment inside the crevice was altered within the experimental time frame only when the external potential was maintained above a certain value. When the external potential exceeded that value, there was an incubation period followed by a rapid increase in current density. This event was succeeded by a decrease in pH and potential inside the crevice. The current density also decreased rapidly upon reversal of the external potential, while a significant reversal of pH occurred over a much longer time. The kinetics of these changes in environment were functions of crevice tightness. A decrease in crevice gap resulted in a greater decrease in pH. Changes in Cl concentration were much more modest, perhaps because of formation of Cl complexes that could not be detected by the silver-silver chloride microelectrode. Chromium depletion on the surface of alloy 825 (UNS N08825) in the crevice resulted in a more rapid decrease in pH even when the surface was rougher. These observations were explained in terms of crevice corrosion nucleation in narrow gaps between peaks of surface asperities, which then propagated laterally to adjoining wider gaps between the peaks and valleys of the asperities.

Sridhar, N.; Dunn, D.S. (Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses)

1994-11-01

156

Amorphous metal alloy and composite  

DOEpatents

Amorphous metal alloys of the iron-chromium and nickel-chromium type have excellent corrosion resistance and high temperature stability and are suitable for use as a protective coating on less corrosion resistant substrates. The alloys are stabilized in the amorphous state by one or more elements of titanium, zirconium, hafnium, niobium, tantalum, molybdenum, and tungsten. The alloy is preferably prepared by sputter deposition.

Wang, Rong (Richland, WA); Merz, Martin D. (Richland, WA)

1985-01-01

157

BRAZING ALLOYS  

Microsoft Academic Search

A brazing alloy which, in the molten state, is characterized by ; excellent wettability and flowability, said alloy being capable of forming a ; corrosion resistant brazed joint wherein at least one component of said joint is ; graphite and the other component is a corrosion resistant refractory metal, said ; alloy consisting essentially of 20 to 50 per cent

R. G. Donnelly; R. G. Gilliland; G. M. Slaughter

1963-01-01

158

VANADIUM ALLOYS  

Microsoft Academic Search

This patent deals with vanadium based ternary alloys useful as fuel ; element jackets. According to the invention the ternary vanadium alloys, ; prepared in an arc furnace, contain from 2.5 to 15% by weight titanium and from ; 0.5 to 10% by weight niobium. Characteristics of these alloys are good thermal ; conductivity, low neutron capture cross section, good

K. F. Smith; R. J. Van Thyne

1959-01-01

159

Influence of Fluidized Bed Quenching on the Mechanical Properties and Quality Index of T6 Tempered B319.2-Type Aluminum Alloys  

NASA Astrophysics Data System (ADS)

The current study aimed to investigate the effect of fluidized sand bed (FB) quenching on the mechanical performance of B319.2 aluminum cast alloys. Traditional water and conventional hot air (CF) quenching media were used to establish a relevant comparison with FB quenching. Quality charts were generated using two models of quality indices to support the selection of material conditions on the basis of the proposed quality indices. The use of an FB for the direct quenching-aging treatment of B319.2 casting alloys yields greater UTS and YS values compared to conventional furnace quenched alloys. The strength values of T6 tempered B319 alloys are greater when quenched in water compared with those quenched in an FB or CF. For the same aging conditions (170°C/4h), the fluidized bed quenched-aged 319 alloys show nearly the same or better strength values than those quenched in water and then aged in a CF or an FB. Based on the quality charts developed for alloys subjected to different quenching media, higher quality index values are obtained by conventional furnace quenched-aged T6-tempered B319 alloys. The modification factor has the most significant effect on the quality results of the alloys investigated, for all heat treatment cycles, as compared to other metallurgical parameters. The results of alloys subjected to multi-temperature aging cycles reveal that the optimum strength properties of B319.2 alloys, however, is obtained by applying multi-temperature aging cycles such as, for example, 240 °C/2 h followed by 170 °C/8 h, rather than T6 aging treatments. The regression models indicate that the mean quality values of B319 alloys are highly quench sensitive due to the formation of a larger percent of clusters in Al-Si-Cu-Mg alloys. These clusters act as heterogeneous nucleation sites for precipitation and enhance the aging process.

Ragab, Kh. A.; Samuel, A. M.; Al-Ahmari, A. M. A.; Samuel, F. H.; Doty, H. W.

2013-06-01

160

Pressure-induced phase transformation of LiIn and LiCd: From NaTl-type phases to {beta}-brass-type alloys  

SciTech Connect

The authors have performed angle-dispersive X-ray powder diffraction experiments on LiGa, LiIn, LiZn, and LiCd at pressures up to 21 GPa using diamond anvil cell techniques. Upon thermal annealing, LiIn and LiCd are both found to undergo phase transformations at a pressure of 11(1) GPa into high-pressure phases with a {beta}-brass (CsCl) structure. Optical reflectivity measurements indicate metallic behavior of the ambient-pressure phrases. Band structure calculations for LiIn confirm the covalent character of the bonding within the diamond-type indium partial structure. The transformation into the CsCl-type phase is associated with a loss of directional In-In bonds.

Schwarz, U.; Braeuninger, S.: Syassen, K. [Max-Planck-Inst. fuer Festkoerperforschung, Stuttgart (Germany); Kniep, R. [Technische Univ., Darmstadt (Germany). Eduard-Zintl-Inst.

1998-04-01

161

The effect of current mode and discharge type on the corrosion resistance of plasma electrolytic oxidation (PEO) coated magnesium alloy AJ62  

Microsoft Academic Search

Magnesium alloys are increasingly being used as lightweight materials in the automotive, defense, electronics, biomaterial and aerospace industries. However, their inherently poor corrosion and wear resistance have, so far, limited their application. Plasma electrolytic oxidation (PEO) in an environmentally friendly aluminates electrolyte has been used to produce oxide coatings with thicknesses of ~80?m on an AJ62 magnesium alloy. Optical emission

R. O. Hussein; P. Zhang; X. Nie; Y. Xia; D. O. Northwood

162

Heusler alloys  

Microsoft Academic Search

In 1903 F. Heusler reported that it was possible to make ferromagnetic alloys from non-ferromagnetic constituents copper-manganese bronze and group B elements such as aluminium and tin. Further investigations showed that the magnetic properties of these alloys are related to their chemical, L21, structure, and to the ordering of the manganese atoms on an f.c.c. sublattice.Heusler alloys are properly described

Peter J. Webster

1969-01-01

163

BRAZING ALLOYS  

DOEpatents

A brazing alloy which, in the molten state, is characterized by excellent wettability and flowability, said alloy being capable of forming a corrosion resistant brazed joint wherein at least one component of said joint is graphite and the other component is a corrosion resistant refractory metal, said alloy consisting essentially of 20 to 50 per cent by weight of gold, 20 to 50 per cent by weight of nickel, and 15 to 45 per cent by weight of molybdenum. (AEC)

Donnelly, R.G.; Gilliland, R.G.; Slaughter, G.M.

1963-02-26

164

Military applications for ? titanium alloys  

NASA Astrophysics Data System (ADS)

Beta alloys are potentially useful for several types of nonaerospace military applications. The potential applications to be discussed in this article include armor, body armor, mortar barrels, and missile launch canisters.

Fanning, J. C.

2005-12-01

165

Influence of Aging Parameters on the Tensile Properties and Quality Index of Al-9 Pct Si-1.8 Pct Cu-0.5 Pct Mg 354-Type Casting Alloys  

NASA Astrophysics Data System (ADS)

The current study was carried out with a view to investigating the influence of age-hardening parameters, aging temperature and time, on the tensile properties and quality indices of a high-strength Al-9 pct Si casting alloy, namely, 354-Al-9 pct Si-1.8 pct Cu-0.5 pct Mg. Quality charts were used as an evaluation tool for selecting the optimum conditions to be applied, in practice, in order to develop high strength and optimum quality in 354 casting alloy. Aging at a low temperature of 428 K (155 °C) was observed to produce the greatest strength and optimum quality in the 354-type castings compared to aging at higher temperatures. The peak strength observed for 354 alloy may be attained after shorter aging times on the condition that the aging temperature is increased. The aging times required for reaching peak strength in 354 alloys are 72 hours, 40 hours, 8 hours, 1 hour, and 15 minutes at aging temperatures of 428 K, 443 K, 468 K, 493 K, and 518 K (155 °C, 170 °C, 195 °C, 220 °C, and 245 °C), respectively. Aging treatment at higher temperatures is accompanied by a reduction in the tensile properties and quality index values of the castings; however, it also introduces the possibility of a significant economical strategy for minimizing the time and the cost of this same treatment. Aging treatment at a lower temperature of 428 K (155 °C) produces fine and dense precipitates displaying smaller interparticle spacing, while at higher aging temperatures, such as 518 K (245 °C), the precipitates are coarser in size, less dense, and more widely dispersed. The quality charts developed in the course of the current research facilitate the interpretation and evaluation of the tensile properties of the 354 alloy. Such charts provide a logical evaluation tool, from the metallurgical point of view, for an accurate prediction of the influence of aging parameters studied on the properties of the alloys. Depending on the required level of tensile properties and based on the quality charts developed, it is possible to make a rigorous selection as to the most suitable aging parameters to be applied to the 354 alloy so as to obtain the best possible cost-effective compromise between alloy strength and quality.

Ammar, H. R.; Samuel, A. M.; Samuel, F. H.; Simielli, E.; Sigworth, G. K.; Lin, J. C.

2012-01-01

166

Alloy development for cladding and duct applications. [LMFBR  

SciTech Connect

Three general classes of materials under development for cladding and ducts are listed. Solid solution strengthened, or austenitic, alloys are Type 316 stainless steel and D9. Precipitation hardened (also austenitic) alloys consist of D21, D66 and D68. These alloys are similar to such commercial alloys as M-813, Inconel 706, Inconel 718 and Nimonic PE-16. The third general class of alloys is composed of ferritic alloys, with current emphasis being placed on HT-9, a tempered martensitic alloy, and D67, a delta-ferritic steel. The program is comprised of three parallel paths. The current reference, or first generation alloy, is 20% cold worked Type 316 stainless steel. Second generation alloys for near-term applications include D9 and HT-9. Third generation materials consist of the precipitation strengthened steels and ferritic alloys, and are being considered for implementation at a later time than the first and second generation alloys. The development of second and third generation materials was initiated in 1974 with the selection of 35 alloys. This program has proceeded to today where there are six advanced alloys being evaluated. These alloys are the developmental alloys D9, D21, D57, D66 and D68, together with the commerical alloy, HT-9. The status of development of these alloys is summarized.

Straalsund, J.L.; Johnson, G.D.

1981-02-02

167

Investigations on the synthesis, structural and microstructural characterizations of Mg-based K 2PtCl 6 type (Mg 2FeH 6) hydrogen storage material prepared by mechanical alloying  

Microsoft Academic Search

This paper deals with the formation of new ternary hydride Mg2FeH6 (K2PtCl6 type) in a single-step procedure following the process of mechanical alloying of initial stoichiometric ingredients Mg and Fe under hydrogen. The optimum yield of formation of single phase Mg2FeH6 was achieved by hydrogen (?10 atm.) milling of constituent elements at a speed of 400 rpm for various milling

S. S. Sai Raman; D. J. Davidson; J.-L. Bobet; O. N. Srivastava

2002-01-01

168

Coherent solubility limits of {gamma}{prime}-type phases in Ni-Al, Ni-Ga and Ni-Ti alloys  

SciTech Connect

One of the predictions of Cahn`s theory of spinodal decomposition in cubic crystals is that the solubility limits of coherent phases in thermodynamic equilibrium can differ from their counterparts in incoherent, unstressed equilibrium. Williams later realized that the equilibrium solubilities limits of coherent phases in a binary alloy should depend on the volume fraction, f, of the two phases, or equivalently, on the overall concentration of solute in the alloy, C{sup o}. The primary objective of this work was therefore to conduct aging experiments on several alloys to measure the coherent solubility limits as a function of the initial alloy content, and to determine whether the shift with C{sup o} could be correlated directly with the magnitude of {delta}.

Li, F.; Ardell, A.J. [Univ. of California, Los Angeles, CA (United States). Dept. of Materials Science and Engineering

1997-10-15

169

Residual stresses in alumina scales grown on different types of Fe–Cr–Al alloys: effect of specimen geometry and cooling rate  

Microsoft Academic Search

Residual stress measurements in alumina scales grown on Fe–Cr–Al alloys were conducted using the ruby fluorescence technique and the results compared with common theoretical considerations. The oxidation experiments were carried out at 1200°C using different Fe–Cr–Al-based materials, different substrate thickness values and varying cooling rates. In case of a conventional wrought alloy the cooling rate significantly influences the residual stress

H. Echsler; E. Alija Martinez; L. Singheiser; W. J. Quadakkers

2004-01-01

170

Nonswelling alloy  

DOEpatents

An aluminum alloy containing one weight percent copper has been found to be resistant to void formation and thus is useful in all nuclear applications which currently use aluminum or other aluminum alloys in reactor positions which are subjected to high neutron doses.

Harkness, S.D.

1975-12-23

171

BRAZING ALLOYS  

Microsoft Academic Search

A brazing alloy is described which, in the molten state, is ; characterized by excellent wettability and flowability and is capable of forming ; a corrosion-resistant brazed joint. At least one component of said joint is ; graphite and the other component is a corrosion-resistant refractory metal. The ; brazing alloy consists essentially of 40 to 90 wt % of

R. G. Donnelly; R. G. Gilliland; G. M. Slaughter

1962-01-01

172

URANIUM ALLOYS  

DOEpatents

Uranium alloys containing from 0.1 to 10% by weight, but preferably at least 5%, of either zirconium, niobium, or molybdenum exhibit highly desirable nuclear and structural properties which may be improved by heating the alloy to about 900 d C for an extended period of time and then rapidly quenching it.

Seybolt, A.U.

1958-04-15

173

Dot arrays of L1{sub 0}-type FePt ordered alloy perpendicular films fabricated using low-temperature sputter film deposition  

SciTech Connect

Using ultrahigh vacuum sputter film deposition, we fabricated L1{sub 0}-type Fe{sub 50}Pt{sub 50} ordered alloy perpendicular films on MgO(001) single-crystal substrates and 2.5 in. glass disks at low substrate temperatures of 200-350 deg. C. Then we examined the magnetic properties of the dot arrays made from these films. The uniaxial magnetic anisotropy K{sub u} for L1{sub 0}-type FePt films (10 nm in thickness) deposited with a Pd underlayer on MgO(001) substrates reached about 2 x 10{sup 7} erg/cm{sup 3} at the substrate temperature T{sub s} of 200 deg. C, and 3 x 10{sup 7} erg/cm{sup 3} at T{sub s} = 250 deg. C. The order parameter S was about 0.46 at T{sub s} = 300 deg. C. Moreover, K{sub u} for L1{sub 0}-FePt films fabricated on glass disks using MgO/Cr underlayers shows 3.4 x 10{sup 7} erg/cm{sup 3} at T{sub s} = 300 deg. C, which was almost equal to that for FePt single-crystal films deposited on Pd/MgO(001). The switching field distribution {sigma}/H{sub c} for dot arrays made from L1{sub 0}-FePt film [5 nm in thickness, on Pd/MgO(001) at T{sub s} = 250 deg. C] was small; {sigma}/H{sub c}= 0.11 for a dot diameter of 15 nm. This value was smaller than that of hcp-Co{sub 75}Pt{sub 25} dot arrays ({sigma}/H{sub c} = 0.18). The difference was mainly attributable to the degree of the easy axis distribution. This result demonstrates the homogeneous formation of a L1{sub 0}-type ordered structure in the FePt layers.

Shimatsu, T.; Aoi, H. [Research Institute of Electrical Communication, Tohoku University, Sendai, 980-8577 (Japan); Inaba, Y.; Kataoka, H. [Research Institute of Electrical Communication, Tohoku University, Sendai, 980-8577 (Japan); Fuji Electric Holdings, Co., Ltd., Matsumoto, 390-0821 (Japan); Sayama, J. [Central Research Laboratory, Hitachi, Ltd., Kanagawa, 256-8510 (Japan); Okamoto, S.; Kitakami, O. [Institute of Multidisciplinary Research for Advanced Material, Tohoku University, Sendai, 980-8577 (Japan)

2011-04-01

174

Alloy development for cladding and duct applications. [LMFBR  

Microsoft Academic Search

Three general classes of materials under development for cladding and ducts are listed. Solid solution strengthened, or austenitic, alloys are Type 316 stainless steel and D9. Precipitation hardened (also austenitic) alloys consist of D21, D66 and D68. These alloys are similar to such commercial alloys as M-813, Inconel 706, Inconel 718 and Nimonic PE-16. The third general class of alloys

J. L. Straalsund; G. D. Johnson

1981-01-01

175

The structure, anisotropy and coercivity of rapidly quenched TbCu7-type SmCo7-xZrx alloys and the effects of post-treatments  

NASA Astrophysics Data System (ADS)

The effects of wheel speed, Zr content, post-ball milling process and heat treatment on the structure, anisotropy, magnetic properties and phase transition of the melt-spun SmCo7-xZrx alloys were investigated. The crystallographic c-axis is parallel to the ribbon plane for the ribbons prepared at low speeds of 5 and 15 m/s, and this orientation is reduced at higher speeds. The out-of-plane coercivity of SmCo6.8Zr0.2 ribbon increases from 123 kA/m for 5 m/s to 1076 kA/m for 60 m/s. Zr doping improves the hard magnetic properties and the in-plane coercivity of SmCo7-xZrx alloys increases with the Zr content from 592 kA/m for x=0.1 to 1376 kA/m for x=0.4. The Rietveld refinements and theoretical analysis reveal that Zr atoms occupy the 2e site. The coercivity mechanisms are different for the alloys with various Zr contents. The ball milling process could enhance the coercivity and remanence of the ribbons due to the grain refinement and the precipitation of Co phase. Heat treatment can further modify the magnetic properties of the alloys. SmCo6.7Zr0.3 alloy heat treated at 400 °C has the high maximum energy product (BH)max of 64.5 kJ/m3, where the coercivity was enhanced to 1560 kA/m by 650 °C heat treatment. In addition, the SmCo7-xZrx alloys exhibit excellent hard magnetic properties at elevated temperatures.

Feng, D. Y.; Liu, Z. W.; Zheng, Z. G.; Zeng, D. C.; Zhang, G. Q.

2013-12-01

176

The fractography of casting alloys  

SciTech Connect

Several types of casting alloys were fractured using various loading modes (uniaxial tension, bending, impact, and torsion, and cyclic stressing), and the corresponding mechanical properties were determined. The unetched and etched fracture surfaces and the microstructures were examined using conventional techniques. The types of casting alloys that were the subjects f these investigations include gray iron, ductile iron, cast steel, and aluminum-base alloys (A380, A356, and 319). The fractographic studies have yielded these generalizations regarding the topography of the fracture surfaces. In the case of low-ductility alloys such as gray iron and the aluminum-base alloys, the tensile edge of a fracture surface produced by a stress system with a strong bending-moment component has a highly irregular contour, whereas the compressive edge of the fracture surface is quite straight and parallel to the bend axis. On the other hand, the periphery of a fracture surface produced by uniaxial tension has a completely irregular contour. The fracture surface produced by cyclic loading of a gray iron does not display any macroscopic evidence (such as a thumb nail) of the loading mode. However, the fracture surface of each of the other casting alloys displays clear, macroscopic evidence of failure induced by fatigue. The aluminum-base alloys fracture completely within the interdendritic region of the microstructure when subjected to monotonic loading by uniaxial tension or bending, whereas a fatigue crack propagates predominantly through the primary crystals of the microstructure.

Powell, G.W. (Ohio State Univ., Columbus, OH (United States))

1994-10-01

177

BRAZING ALLOYS  

DOEpatents

A brazing alloy is described which, in the molten state, is characterized by excellent wettability and flowability and is capable of forming a corrosion-resistant brazed joint. At least one component of said joint is graphite and the other component is a corrosion-resistant refractory metal. The brazing alloy consists essentially of 40 to 90 wt % of gold, 5 to 35 wt% of nickel, and 1 to 45 wt% of tantalum. (AEC)

Donnelly, R.G.; Gilliland, R.G.; Slaughter, G.M.

1962-02-20

178

COATED ALLOYS  

DOEpatents

A coating is described for iron group metals and alloys, that is particularly suitable for use with nickel containing alloys. The coating is glassy in nature and consists of a mixture containing an alkali metal oxide, strontium oxide, and silicon oxide. When the glass coated nickel base metal is"fired'' at less than the melting point of the coating, it appears the nlckel diffuses into the vitreous coating, thus providing a closely adherent and protective cladding.

Harman, C.G.; O' Bannon, L.S.

1958-07-15

179

Ferromagnetic bulk amorphous alloys  

NASA Astrophysics Data System (ADS)

This article reviews our recent results on the development of ferromagnetic bulk amorphous alloys prepared by casting processes. The multicomponent Fe-(Al,Ga)-(P,C,B,Si) alloys are amorphized in the bulk form with diameters up to 2 mm, and the temperature interval of the supercooled liquid region before crystallization is in the range of 50 to 67 K. These bulk amorphous alloys exhibit good soft magnetic properties, i.e., high B s of 1.1 to 1.2 T, low H o of 2 to 6 A/m, and high ? e of about 7000 at 1 kHz. The Nd-Fe-Al and Pr-Fe-Al bulk amorphous alloys are also produced in the diameter range of up to 12 mm by the copper mold casting process and exhibit rather good hard magnetic properties, i.e., B r of about 0.1 T, high H o of 300 to 400 kA/m, and rather high ( JH)max of 13 to 20 kJ/m3. The crystallization causes the disappearance of the hard magnetic properties. Furthermore, the melt-spun Nd-Fe-Al and Pr-Fe-Al alloy ribbons exhibit soft-type magnetic properties. Consequently, the hard magnetic properties are concluded to be obtained only for the bulk amorphous alloys. The bulk Nd- and Pr-Fe-Al amorphous alloys have an extremely high T x/Tm of about 0.90 and a small ? T m(= T m- T x) of less than 100 K and, hence, their large glass-forming ability is due to the steep increase in viscosity in the supercooled liquid state. The high T x/Tm enables the development of a fully relaxed, clustered amorphous structure including Nd-Nd and Nd-Fe atomic pairs. It is, therefore, presumed that the hard magnetic properties are due to the development of Nd-Nd and Nd-Fe atomic pairs with large random magnetic anisotropy. The Nd- and Pr-based bulk amorphous alloys can be regarded as a new type of clustered amorphous material, and the control of the clustered amorphous structure is expected to enable the appearance of novel functional properties which cannot be obtained for an ordinary amorphous structure.

Inoue, Akihisa; Takeuchi, Akira; Zhang, Tao

1998-07-01

180

[Composition and morphology of oxides on porcelain fused to Ni-Cr alloys. Be containing alloys].  

PubMed

Bonding strength between porcelain and Ni-Cr alloy for the porcelain fused-to metal crown in which Be is contained in the alloy is known to be higher than those in which Be is not contained. Since, bonding between porcelain and alloy is the reaction of oxides and porcelain, the bonding is thought to be influenced by the quality the oxides film which forms on the alloy surface. The purpose of this study was to determine the composition and morphology of the oxides formed on both Be containing and non-Be contained Ni-Cr alloys. The oxides analysis was done using an EPMA and Auger analysis. Also, the Porcelain/Ni-Cr alloy interface was observed by a scanning electron microscope (SEM). The following results are indicated from this investigation: 1. The oxides from the alloys not containing Be are corundum type Cr2O3 and spinel type NiCr2O4. These oxide layers are uniform, thick and porous and the adhesion to alloy is poor. 2. The oxides from alloy containing Be is BeO only. The BeO is uniform, thin and condensed. The adhesion to the alloy is good. 3. The oxide layer formed when the porcelain is fused to alloy containing Be is thin (1 micron average) and has good adhesion to alloy. 4. Be is selectively oxidized and controlled the form of Cr2O3 and NiO. PMID:2700282

Watanabe, T

1989-06-01

181

Liquid lithium self-cooled breeding blanket design for ITER  

Microsoft Academic Search

To meet the technical objectives of the ITER extended performance phase (EPP) an advanced tritium breeding lithium\\/vanadium (Li\\/V) blanket was developed by two home teams (US and RF). The design is based on the use of liquid Li as coolant and breeder and vanadium alloy (V-Cr-Ti) as structural material. The first wall is coated with a beryllium protection layer. Beryllium

I. R Kirillov; I. V Danilov; S. I Sidorenkov; Yu. S Strebkov; R. F Mattas; Y Gohar; T. Q Hua; D. L Smith

1998-01-01

182

Chemical Milling Solution for Titanium Alloys.  

National Technical Information Service (NTIS)

A new type of chemical milling solution for titanium alloys has been proposed and investigated. The solution is a mixture type, prepared from hydrofluoric and nitric acid, with excellent milling characteristics. High milling speed with good surface qualit...

D. Li L. Jin Z. Huang

1995-01-01

183

Miscibility gaps and spinodal decomposition in III/V quaternary alloys of the type A/sub x/B/sub y/C/sub 1-x/-yD  

SciTech Connect

Thermodynamic concepts have been developed for the calculation of solid-phase miscibility gaps and spinodal decomposition in quaternary alloys of the type A/sub x/B/sub y/C/sub 1-x/-yD. These concepts have been applied to the analysis of III/V quaternary alloys using the delta-lattice-parameter (DLP) solution model. In addition, the effects of coherency strain energy have been included in the calculation. Results are presented for the systems Al/sub x/Ga/sub y/In/sub 1-x/-yP, Al/sub x/Ga/sub y/In/sub 1-x/-yAs, InP/sub x/As/sub y/Sb/sub 1-x/-y, and GaP/sub x/As/sub y/Sb/sub 1-x/-y. Even though these systems all have miscibility gaps, they are shown to be stable against spinodal decomposition at all temperatures due to the elastic strain energy inherent in coherent decomposition of single crystalline alloys.

Stringfellow, G.B.

1983-01-01

184

High-resolution soft x-ray photoelectron study of density of states and thermoelectric properties of the Heusler-type alloys (Fe2\\/3V1\\/3)100-yAly  

Microsoft Academic Search

The high-resolution soft x-ray photoelectron study of Heusler(L21) -type (Fe2\\/3V1\\/3)100-yAly (y=23.8-25.8) alloys directly confirms the correlation between their thermoelectric properties and the electronic structures near the Fermi level. It shows the rigid-band-like shift of the main 3d bands and the increase of the photoelectron intensity at the Fermi edge with the small deviation of the Al content from stoichiometry, i.e.,

K. Soda; H. Murayama; K. Shimba; S. Yagi; J. Yuhara; T. Takeuchi; U. Mizutani; H. Sumi; M. Kato; H. Kato; Y. Nishino; A. Sekiyama; S. Suga; T. Matsushita; Y. Saitoh

2005-01-01

185

Bond Strength of Gold Alloys Laser Welded to Cobalt-Chromium Alloy  

PubMed Central

The objective of this study was to investigate the joint properties between cast gold alloys and Co-Cr alloy laser-welded by Nd:YAG laser. Cast plates were fabricated from three types of gold alloys (Type IV, Type II and low-gold) and a Co-Cr alloy. Each gold alloy was laser-welded to Co-Cr using a dental laser-welding machine. Homogeneously-welded and non-welded control specimens were also prepared. Tensile testing was conducted and data were statistically analyzed using ANOVA. The homogeneously-welded groups showed inferior fracture load compared to corresponding control groups, except for Co-Cr. In the specimens welded heterogeneously to Co-Cr, Type IV was the greatest, followed by low-gold and Type II. There was no statistical difference (P<0.05) in fracture load between Type II control and that welded to Co-Cr. Higher elongations were obtained for Type II in all conditions, whereas the lowest elongation occurred for low-gold welded to Co-Cr. This study indicated that, of the three gold alloys tested, the Type IV gold alloy was the most suitable alloy for laser-welding to Co-Cr.

Watanabe, Ikuya; Wallace, Cameron

2008-01-01

186

Near-forward Raman scattering by bulk and surface phonon-polaritons in the model percolation-type ZnBeSe alloy  

NASA Astrophysics Data System (ADS)

We study the bulk and surface phonon-polaritons of the Zn0.67Be0.33Se zincblende alloy by near-forward Raman scattering. The short (Be-Se) bond exhibits a distinct percolation doublet in the conventional backscattering Raman spectra, corresponding to a three-mode behavior in total [1×(Zn-Se), 2×(Be-Se)] for Zn0.67Be0.33Se. This offers an opportunity to achieve a refined understanding of the phonon-polariton modes of a zincblende alloy beyond the current two-mode approximation, corresponding to a [1×(Zn-Se), 1×(Be-Se)] description in the present case. The discussion is supported by contour modeling of the Raman signals of the multi-mode bulk and surface phonon-polaritons within the formalism of the linear dielectric response.

Hajj Hussein, R.; Pagès, O.; Firszt, F.; Paszkowicz, W.; Maillard, A.

2013-08-01

187

Orthodontic silver brazing alloys.  

PubMed

Orthodontic silver brazing alloys suffer from the presence of cadmium, excessive flow temperatures, and crevice corrosion on stainless steel. Seven alloys were examined. Two alloys contained cadmium. The lowest flow temperature observed was 629 degrees C for a cadmium alloy and 651 degrees C for two cadmium free alloys. Three alloys had corrosion resistance superior to the other solders. Addition of low melting temperature elements gallium and indium reduced flow temperature in some cases but produced brittleness in the brazing alloy. PMID:2576971

Brockhurst, P J; Pham, H L

1989-10-01

188

Structural relaxation of the melt-spun icosahedral phase and a new type of approximant in Al-Cu-Ru alloys  

Microsoft Academic Search

The formation range and thermal stability of the icosahedral phase produced by melt spinning were investigated in ternary Al?Cu?Ru alloys by X-ray diffraction and transmission electron microscopy. The stable face-centred icosahedral (FCI) phase is formed in a wide region where the condition for the valence electron-to-atom ratio e\\/a?1·75 is satisfied. Shifts of diffraction peaks to larger angles were observed during

K. Araki; A. Waseda; K. Kimura; H. Ino

1993-01-01

189

High temperature properties of several chromium-containing Co-based alloys reinforced by different types of MC carbides (M = Ta, Nb, Hf and\\/or Zr)  

Microsoft Academic Search

Five cast cobalt alloys based on Co–8Ni–30Cr–0.4\\/0.45C and containing Ta, Nb, Hf and\\/or Zr were studied by metallography in the as-cast condition and after treatments at 1300°C. The obtained MC carbides were all interdendritic with a eutectic script-like morphology. For similar carbon contents, the HfC carbides are the most developed in the as-cast microstructure and the most stable at 1300°C.

Patrice Berthod

2009-01-01

190

The formation of a rock-salt type ZnO thin film by low-level alloying with MgO  

Microsoft Academic Search

A high pressure form of ZnO with a rock-salt structure can be synthesized as a thin film by a pulsed laser deposition technique when {\\\\ge }15 mol% of MgO is alloyed. The phase is identified both by x-ray diffraction and near edge x-ray absorption fine structure (NEXAFS) measurements. NEXAFS is interpreted with the aid of first principles calculations employing a

M. Kunisu; I. Tanaka; T. Yamamoto; T. Suga; T. Mizoguchi

2004-01-01

191

The qualitative effects of various types of hygiene instrumentation on commercially pure titanium and titanium alloy implant abutments: an in vitro and scanning electron microscope study  

Microsoft Academic Search

Statement of problem. Implant survival depends on proper and timely oral hygiene maintenance, and a wide variety of oral prophylaxis procedures have been recommended and used on implant abutments.Purpose. This in vitro study compared the surface quality of both commercially pure titanium and titanium-alloy implant abutments, subjected to various hygiene methods and instruments with a standardized, clinically applicable scaling force.Material

Frieda Von Giese Brookshire; William W. Nagy; Virendra B. Dhuru; Gerald J. Ziebert; Srinivas Chada

1997-01-01

192

Amorphous metal alloys produced by mechanical alloying  

Microsoft Academic Search

Mechanical alloying is a powder metallurgy method used in commercial production of high temperature superalloys. Under specific conditions, mechanical alloying allows the synthesis of amorphous metal alloys from mixtures of pure metal powders or from the powders of intermetallic compounds. Because the amorphizing transformation during mechanical alloying is a solid state reaction, most of the difficulties related to the amorphization

T. J. Tiainen; R. B. Schwarz

1989-01-01

193

Tritium Production from Palladium Alloys  

SciTech Connect

A number of palladium alloys have been loaded with deuterium or hydrogen under low energy bombardment in a system that allows the continuous measurement of tritium. Long run times (up to 200 h) result in an integration of the tritium and this, coupled with the high intrinsic sensitivity of the system ({approximately}0.1 nCi/l), enables the significance of the tritium measurement to be many sigma (>10). We will show the difference in tritium generation rates between batches of palladium alloys (Rh, Co, Cu, Cr, Ni, Be, B, Li, Hf, Hg and Fe) of various concentrations to illustrate that tritium generation rate is dependent on alloy type as well as within a specific alloy, dependent on concentration.

Claytor, T.N.; Schwab, M.J.; Thoma, D.J.; Teter, D.F.; Tuggle, D.G.

1998-04-19

194

Production of Aluminum Alloys: Status and Prospects  

Microsoft Academic Search

Due to their physico-mechanical properties, aluminum alloys are one of the most important structural materials presently in use. Aluminum alloys are second only to steel in terms of volume of production and substantially outstrip other nonferrous metals in this regard. For example, the worldwide production of different types of metals at the end of the last century broke down as

G. S. Makarov

2002-01-01

195

Castability, opaque masking, and porcelain bonding of 17 porcelain-fused-to-metal alloys.  

PubMed

Seventeen porcelain-fused-to-metal alloys, which represented a cross section of the various alloy types available, were evaluated for castability, opaque masking, and porcelain bond strength. The base metal alloys generally cast more completely than the noble alloys, with the presence of beryllium as an important factor for greater castability among the base metal alloys. Statistically significant differences were observed in the ability of an opaque porcelain to mask the different alloy substrates but no systematic effect of alloy type was observed. Porcelain bond testing revealed that nickel-chromium-beryllium alloys produced significantly better porcelain-metal bonds than nickel-chromium alloys without beryllium. In addition, it was found that palladium-copper alloys produced significantly better bonds with porcelain than palladium-cobalt alloys. PMID:8642521

O'Connor, R P; Mackert, J R; Myers, M L; Parry, E E

1996-04-01

196

Anomalous codeposition of Co–Ni: alloys from gluconate baths  

Microsoft Academic Search

Thin films of cobalt–nickel alloys were galvanostatically deposited onto steel substrates from gluconate baths. Cathodic polarization\\u000a curves were determined for the parent metals and Co–Ni alloy. The effects of bath composition, current density and temperature\\u000a on cathodic current efficiency (CCE) and alloy composition were studied. The deposition of Co–Ni alloy is of anomalous type,\\u000a in which the less noble metal

M. M. Kamel

2007-01-01

197

Advanced cutting conditions for the milling of aeronautical alloys  

Microsoft Academic Search

This paper deals with possible improvement aspects on the chip cutting milling of two alloys that are used frequently in the aerospace industry, in particular the titanium alpha–beta-based alloy Ti6Al4V and the nickel alloy usually known as type 718. Both alloys are used widely in the manufacture of different turbo-engine parts, considering their excellent mechanic features, and their resistance to

L. N López de lacalle; J Pérez; J. I Llorente; J. A Sánchez

2000-01-01

198

Environmental Cracking of Corrosion Resistant Alloys in the Chemical Process Industry - A Review  

SciTech Connect

A large variety of corrosion resistant alloys are used regularly in the chemical process industry (CPI). The most common family of alloys include the iron (Fe)-based stainless steels, nickel (Ni) alloys and titanium (Ti) alloys. There also other corrosion resistant alloys but their family of alloys is not as large as for the three groups mentioned above. All ranges of corrosive environments can be found in the CPI, from caustic solutions to hot acidic environments, from highly reducing to highly oxidizing. Stainless steels are ubiquitous since numerous types of stainless steels exist, each type tailored for specific applications. In general, stainless steels suffer stress corrosion cracking (SCC) in hot chloride environments while high Ni alloys are practically immune to this type of attack. High nickel alloys are also resistant to caustic cracking. Ti alloys find application in highly oxidizing solutions. Solutions containing fluoride ions, especially acid, seem to be aggressive to almost all corrosion resistant alloys.

Rebak, R B

2006-12-04

199

Thermoelectric performance of nanostructured p-type Zr0.5Hf0.5Co0.4Rh0.6Sb1-xSnx half-Heusler alloys  

NASA Astrophysics Data System (ADS)

Several compositions of the p-type half-Heusler alloys Zr0.5Hf0.5Co0.4Rh0.6Sb1-xSnx (0?x?0.4) were synthesized by mechanically alloying high purity elemental powders using hardened steel jars and balls on a high energy shaker mill. Powder X-ray diffraction (XRD) investigations of several aliquots taken after regularly spaced milling time suggested that single phase products with half-Heusler (HH) structure can be obtained after 10 h. However, XRD and transmission electron microscopy (TEM) studies of several specimens obtained from compacted polycrystalline powders of Zr0.5Hf0.5Co0.4Rh0.6Sb1-xSnx alloys using a uniaxial hot press (HP) revealed the presence of CoSb inclusions with various sizes embedded inside the HH matrix. Hall effect, electrical conductivity, and thermopower data collected between 300 K and 775 K on several compositions suggested that electronic transport in the synthesized Zr0.5Hf0.5Co0.4Rh0.6Sb1-xSnx/CoSb composites strongly depends on the average size and/or mole fraction of the embedded CoSb inclusions rather than the fraction (x) of Sn substituting for Sb. Among the samples investigated, the nanocomposite with x=0.2, which contains nanometer-scale CoSb inclusions, showed the largest power factor (800 ?W/K2 m at 775 K) and the lowest lattice thermal conductivity (˜2.2 W/m K at 775 K) leading to a six-fold enhancement in the figure of merit when compared to the Zr0.5Hf0.5Co0.4Rh0.6Sb0.99Sn0.01 bulk matrix.

Maji, Pramathesh; Makongo, Julien P. A.; Zhou, Xiaoyuan; Chi, Hang; Uher, Ctirad; Poudeu, Pierre F. P.

2013-06-01

200

Influence of finishing on the electrochemical properties of dental alloys.  

PubMed

Dental alloy surface finishing procedures of may influence their electrochemical behavior, which is used to evaluate their corrosion resistance. We examined the polarization resistance and potentiodynamic polarization profile of the precious-metal alloys, Type 4 gold alloy and silver-palladium alloy, and the base-metal alloys, nickel-chromium alloy, cobalt-chromium alloy, and CP-titanium. Three types of finishing procedure were examined: mirror-finishing using 0.05 micron alumina particles, polishing using #600 abrasive paper and sandblasting. Dissolution of the alloy elements in 0.9% NaCl solution was also measured and compared with the electrochemical evaluation. The corrosion resistance of the dental alloys was found to relate to finishing as follows: The polarization resistance and potentiodynamic polarization behavior revealed that the corrosion resistance improved in the order of sandblasting, #600-abrasive-paper polishing, and mirror-finishing. While the corrosion potential, critical current density and passive current density varied depending on the type of finishing, the transpassive potential remained unchanged. The influence of finishing on the corrosion resistance of precious-metal alloys was less significant than on that of base-metal alloys. A mirror-finishing specimen was recommended for use in evaluation of the corrosion resistance of various dental alloys. PMID:11212579

Kaneko, T; Hattori, M; Hasegawa, K; Yoshinari, M; Kawada, E; Oda, Y

2000-05-01

201

Study on Improvement of Casting Conditions for Some Aluminum Bronze Alloys  

Microsoft Academic Search

Two types of aluminium bronze alloys have been studied to determine the proper methods of melting and casting in two different conditions; with treating materials as (Albral 2, Logas 50 and deoxidizing tube E3) and without and determine the effects of these conditions on mechanical properties of alloys. These alloys are :- a) Aluminium bronze alloys (AB1). b) Nickel-aluminium bronze

Sami A. Ajeel; Ahmed N. Ibrahiem; Abdul Salam; A. Fadhil

202

High Performance Titanium Alloys.  

National Technical Information Service (NTIS)

Original titanium alloys appropriate for various uses have been developed. A cost effective corrosion resistant Ti alloy was developed utilizing small effective addition of 0.05% Pd. High strength and high toughness alpha + Beta alloys were developed by t...

M. Okada W. Takahashi T. Maeda Y. Shida T. Fukuda

1990-01-01

203

Boron alloy  

SciTech Connect

This paper describes a ferro-boron alloy produced in situ in a basic oxygen furnace, an induction furnace, or an electric furnace, or in combination with a mixing vessel. It comprises: 1.4% to 15% by weight boron; less than 0.002% by weight nitrogen; less than about 0.2% by weight carbon; less than about 0.01% by weight aluminum; and the balance iron with minute amounts of residuals.

Sussman, R.C.; Evans, L.G.

1990-06-26

204

Interactions of hydrogen with Tb{sub 3}Ni{sub 6}M{sub 2} (M = Al, Ga, or Si) alloys with structures of Ce{sub 3}Ni{sub 6}Si{sub 2} type  

SciTech Connect

Studies have been made on the interactions with hydrogen for intermetallides of the rare-earth metals (REM) REM{sub 3}Ni{sub 6}M{sub 2} (M=Al, Ga, or Si) with structures of Ce{sub 3}Ni{sub 6}Si{sub 2} type. They are considered as promising materials for researching hydrogen sorption because they have close to optimal ratio of the REM to Ni (1:2) for effective hydrogen-accumulating alloys and also increased cavity volumes in the metal matrix and suitable properties in the components of the intermetallides aluminum, gallium, and silicon, while the sizes of the atoms are greater than those of the nickel atom. 9 refs., 2 figs., 1 tab.

Yartis, V.A.; Pavlen, V.V. [Karpenko Physicomechanics Inst., L`viv (Ukraine)

1992-01-01

205

Rhenium Alloying of Tungsten Heavy Alloys.  

National Technical Information Service (NTIS)

Alloying experiments have been performed using rhenium additions to a classic 90 mass % tungsten heavy alloy. The mixed powder system was liquid phase sintered to full density at 1500 C in 60 min The rhenium modified alloys exhibited a smaller grain size,...

R. M. German A. Bose G. Jerman

1989-01-01

206

Long-term corrosion studies in vitro of gold, cobalt-chromium, and nickel-chromium alloys in contact.  

PubMed

Specimens of various types of dental casting alloys were stored in phosphate-buffered 0.9% NaCl solution for 35 weeks. Every 7 weeks the solutions were changed and analyzed with regard to elements released from the alloys. The release of Cu from type III gold alloy increased in contact with gold alloys for metallo-ceramic use in a 1:2 area relation. However, when the area relation was reversed, no difference in the amounts of elements released was observed. Crevice corrosion was initiated with one of the Co-Cr alloys in contact with type III gold alloy. The crevice corrosion increased the amounts of Co and Cr released into the solutions. The release of Ni and Cr from the Ni-Cr alloys was prominent. These alloys were very susceptible to crevice corrosion. With one of the Ni-Cr alloys the release of elements increased in contact with type III gold alloy. PMID:3864340

Moberg, L E

1985-08-01

207

Structural alloys for high field superconducting magnets  

SciTech Connect

Research toward structural alloys for use in high field superconducting magnets is international in scope, and has three principal objectives: the selection or development of suitable structural alloys for the magnet support structure, the identification of mechanical phenomena and failure modes that may influence service behavior, and the design of suitable testing procedures to provide engineering design data. This paper reviews recent progress toward the first two of these objectives. The structural alloy needs depend on the magnet design and superconductor type and differ between magnets that use monolithic and those that employ force-cooled or ICCS conductors. In the former case the central requirement is for high strength, high toughness, weldable alloys that are used in thick sections for the magnet case. In the latter case the need is for high strength, high toughness alloys that are used in thin welded sections for the conductor conduit. There is productive current research on both alloy types. The service behavior of these alloys is influenced by mechanical phenomena that are peculiar to the magnet environment, including cryogenic fatigue, magnetic effects, and cryogenic creep. The design of appropriate mechanical tests is complicated by the need for testing at 4/sup 0/K and by rate effects associated with adiabatic heating during the tests. 46 refs.

Morris, J.W. Jr.

1985-08-01

208

Precipitation hardened nickel-base alloys for sour gas environments  

SciTech Connect

SCC (Stress Corrosion Cracking) in sour gas environments of ..gamma..'(gamma prime: Ni/sub 3/(Ti and/or Al)) and ..gamma..''(gamma double prime: Ni/sub 3/Nb) precipitation hardened nickel-base alloys has been studied using the SSRT (Slow Strain Rate Tensile) test, anodic polarization measurement and transmission electron microscopy (TEM). The ..gamma..'-type alloy containing Ti was more susceptible to SCC in the SSRT tests up to 350/sup 0/F(450 K) than the ..gamma..''-type alloy containing Nb. The susceptibility to SCC was related to their deformation structures in terms of stress localization and sensitivity to pitting corrosion in H/sub 2/S solutions. TEM observation showed the ..gamma..'-type alloy deformed by the superlattice dislocations in coplanar structures. This mode of deformation induced the stress localization to some boundaries such as grain boundary and as a result the susceptibility to SCC of the ..gamma..'-type alloy was increased. On the other hand, the ..gamma..''-type alloy deformed by the massive dislocation not in coplanar structures so that it was less susceptible to SCC in terms of the stress localization. The anodic polarization measurement suggested the ..gamma..'-type alloy was more susceptible to pitting corrosion compared with the ..gamma..''-type alloy.

Igarashi, M.; Mukai, S.; Kudo, T.; Okada, Y.; Ikeda, A.

1987-01-01

209

Corrosion Testing of Ni Alloy HVOF Coatings in High Temperature Environments for Biomass Applications  

NASA Astrophysics Data System (ADS)

This paper reports the corrosion behavior of Ni alloy coatings deposited by high velocity oxyfuel spraying, and representative boiler substrate alloys in simulated high temperature biomass combustion conditions. Four commercially available oxidation resistant Ni alloy coating materials were selected: NiCrBSiFe, alloy 718, alloy 625, and alloy C-276. These were sprayed onto P91 substrates using a JP5000 spray system. The corrosion performance of the coatings varied when tested at ~525, 625, and 725 °C in K2SO4-KCl mixture and gaseous HCl-H2O-O2 containing environments. Alloy 625, NiCrBSiFe, and alloy 718 coatings performed better than alloy C-276 coating at 725 °C, which had very little corrosion resistance resulting in degradation similar to uncoated P91. Alloy 625 coatings provided good protection from corrosion at 725 °C, with the performance being comparable to wrought alloy 625, with significantly less attack of the substrate than uncoated P91. Alloy 625 performs best of these coating materials, with an overall ranking at 725 °C as follows: alloy 625 > NiCrBSiFe > alloy 718 ? alloy C-276. Although alloy C-276 coatings performed poorly in the corrosion test environment at 725 °C, at lower temperatures (i.e., below the eutectic temperature of the salt mixture) it outperformed the other coating types studied.

Paul, S.; Harvey, M. D. F.

2013-03-01

210

Hydrogen diffusion in Al-Li alloys  

Microsoft Academic Search

The diffusion coefficients of hydrogen in binary Al-Li alloys containing 1,2, and 3 wt pct Li have been determined from desorption\\u000a curves of samples saturated with hydrogen at 473 to 873 K. Within this temperature range, the diffusivity of hydrogen in the\\u000a binary Al-Li alloys investigated has an Arrhenius-type temperature dependence and follows the equation of the general formD =

P. N. Anyalebechi

1990-01-01

211

Development of a carburizing stainless steel alloy  

Microsoft Academic Search

A new carburizing stainless steel alloy that resists corrosion, heat, and fatigue has been developed for bearing and gear applications. Pyrowear 675 Stainless alloy is vacuum induction melted and vacuum arc remelted (VIM\\/VAR) for aircraft-quality cleanliness. Test results show that it has corrosion resistance similar to that of AISI Type 440-C stainless, and its rolling fatigue resistance is superior to

Wert

1994-01-01

212

The morphology of martensite in iron alloys  

Microsoft Academic Search

Light and electron microscopy have been used to determine the main structural differences between the two major types of martensite\\u000a in ferrous alloys. In the martensite that forms in dilute alloys of iron, the basic transformation unit takes the shape of\\u000a a lath, and hence the term lath martensite is appropriate for identifying this morphology. Each lath is the result

G. Krauss; A. R. Marder

1971-01-01

213

Twin roll casting of aluminum alloy strips  

Microsoft Academic Search

Two kinds of twin roll caster for aluminum alloys were devised in the present study. Vertical type was adopted. The strip, which was thinner than 3mm, could be cast at speeds higher than 60m\\/min. Aluminum alloy, which freezing zone is very wide like A5182, could be cast using the twin roll caster of the present study at speeds up to

Toshio Haga; Kenta Tkahashi; Masaaki Ikawaand; Hisaki Watari

2004-01-01

214

Enhancement of p-type conduction in Ag-doped ZnO thin films via Mg alloying: The role of oxygen vacancy  

NASA Astrophysics Data System (ADS)

ZnO, ZnMgO, Ag-doped ZnO (ZnO:Ag), and Ag-doped ZnMgO (ZnMgO:Ag) thin films have been prepared by pulsed laser deposition. All the films have a preferred orientation with the c-axis perpendicular to the substrates. Hall-effect measurements indicate that the ZnO:Ag film exhibits p-type conduction, but obviously worse than that of the ZnMgO:Ag film. A comparative study of p-type ZnO:Ag and ZnMgO:Ag films using photoluminescence and x-ray photoelectron spectroscopy measurements shows that the enhanced p-type conduction in ZnMgO:Ag film is closely related to the increase of the activation energy of the intrinsic donors and the suppression of charge-compensating oxygen-related defects after Mg incorporation.

Cao, Ling; Zhu, Liping; Ye, Zhizhen

2013-05-01

215

On the Formation of non-metallic inclusions in fe-50 pct Ni type alloys by deoxidation with Mn, Si, and Al  

NASA Astrophysics Data System (ADS)

This investigation deals with deoxidation experiments in 30 g lab melts of Fe-50 pct Ni alloys. After deoxidation with different amounts of Mn, Si and Al and their combinations the samples were quenched into water at different times. Metallographic studies comprising light microscopy, scanning electron microscopy, electron microprobe and image analysis were performed. Classical nucleation theory was used for computation of the different supersaturation with oxygen or the deoxidant necessary for homogeneous nucleation. The different deoxidation reactions and the transformation of inclusions due to diffusion of oxygen, or the deoxidant, from or into the inclusions was treated for the different cases of deoxidation. Most deoxidation reactions take place within some seconds. The experimental results were to be used to estimate the pertinent interfacial tensions between the oxides and the melt and the values obtained for the different oxides seemed to be reasonable. The diffusional computations were successfully used for predicting the different transformations taking place. For example, in deoxidation with 0.03 pct Si the oxygen solubility is controlled by the equilibrium with liquid FeO ? SiO2. The time taken to reach equilibrium is determined by the number of inclusions and the particle size. In deoxidation with 0.1 pct Si or more, the equilibrium is controlled by SiO2 inclusions and the time taken to reach equilibrium, less than 1 s, is much shorter compared to the samples with 0.03 pct Si. The deoxidation reactions with aluminum were treated in the same way, and it was shown that the number of particles determined the time elapsing before equilibrium with respect to the formation of FeOAl2O3 or A12O3. It was further shown that transformation of primary liquid FeOAl2O3 with high contents of FeO into solid FeOAl2O3 was expected to occur within one second. However, the experiments showed that it took somewhat longer, due to formation of solid FeOAl2O3 around the liquid FeOAl2O3 inclusions, thereby preventing the diffusion of aluminum into the particles.

Fredriksson, Hasse; Hammar, Örjan

1980-09-01

216

Comparison of A15 Stoichiometry and Grain Morphology in Internal sn and Tube Type Strands; Influence of Strand Design, HTs and Alloying  

NASA Astrophysics Data System (ADS)

A15 stoichiometry was investigated and compared for two different Nb3Sn strand designs, ``tube type'' and high-performance, distributed-barrier RIT type. The focus of the study was to attain fine grain A15 with maximal Sn stoichiometry. Tube type conductors were compared to RIT conductors, each after the application of two-step HTs with plateaus ranging from 615° C to 675° C for various times. The resulting transport values were compared to those arising from standard HTs, namely 3476 A/mm2 for the RIT conductors and 2231 A/mm2 for the tube type conductors. The influence of strand geometry and reaction route was related to the resulting A15 stoichiometries. Short sections of strand were encapsulated and then HT, after which SEM (BSE) and EDS were used to observe the structures and obtain Sn concentration profiles. Fractography was performed to investigate the effect of a two-step reaction on the morphology, the ratio of coarse/fine grain area and grain size of fine grain A15.

Bhartiya, S.; Sumption, M. D.; Peng, X.; Gregory, E.; Tomsic, M. J.; Doll, D.; Collings, E. W.

2010-04-01

217

Weldability of intermetallic alloys  

SciTech Connect

Ordered intermetallic alloys are a unique class of material that have potential for structural applications at elevated temperatures. The paper describes the welding and weldability of these alloys. The alloys studied were nickel aluminide (Ni[sub 3]Al), titanium aluminide (Ti[sub 3]Al), and iron aluminide.

David, S.A. (Oak Ridge National Lab., TN (United States))

1990-01-01

218

PLUTONIUM-ZIRCONIUM ALLOYS  

Microsoft Academic Search

A series of nuclear reactor fuel alloys consisting of from about 5 to ; about 50 at.% zirconium (or higher zirconium alloys such as Zircaloy), balance ; plutonium, and having the structural composition of a plutonium are described. ; Zirconium is a satisfactory diluent because it alloys readily with plutonium and ; has desirable nuclear properties. Additional advantages are corrosion

F. W. Schonfeld; J. T. Waber

1960-01-01

219

NICKEL-BASE ALLOY  

Microsoft Academic Search

A nickel-base alloy was developed which is particularly useful for the ; containment of molten fluoride salts in reactors. The alloy is resistant to both ; salt corrosion and oxidation and may be used at temperatures as high as 1800 deg ; F. Basically, the alloy consists of 15 to 22 wt.% molybdenum, a small amount of ; carbon, and

H. Inouye; W. D. Manly; T. K. Roche

1960-01-01

220

SUPERCONDUCTING VANADIUM BASE ALLOY  

DOEpatents

A new vanadium-base alloy which possesses remarkable superconducting properties is presented. The alloy consists of approximately one atomic percent of palladium, the balance being vanadium. The alloy is stated to be useful in a cryotron in digital computer circuits.

Cleary, H.J.

1958-10-21

221

Prediction of intercluster separation and Schottky-type heat-capacity contribution in surface-segregated binary and ternary alloy nanocluster systems  

NASA Astrophysics Data System (ADS)

Site-specific average atomic concentrations computed for systems of Rh-Cu, Ni-Cu and Rh-Ni-Cu icosahedral and cuboctahedral free nanoclusters of different sizes by the “free-energy concentration expansion method” are used for evaluating pertinent cluster thermodynamic functions. Compared to stable surface segregated “magic-number” structures, at intermediate overall compositions the cluster system is expected to separate into these “phases.” A Schottky-type heat-capacity anomaly is predicted and attributed to atomic exchange (e.g., desegregation) excitation processes. Its measurement can elucidate the cluster segregation energetics.

Polak, Micha; Rubinovich, Leonid

2005-03-01

222

Evaluation of alternative alloys for PWR steam generator tubing. Final report  

SciTech Connect

This final report summarizes the results of a project to evaluate alternative alloys for use as PWR steam generator tubing. A literature survey identified alloys 690 and 800 in the mill annealed condition and alloys 600 and 690 after annealing at 705/sup 0/C (1300/sup 0/F) for 15 hours as candidate alloys. Mill annealed alloy 600 was included as a control. C-ring tests were carried out in four secondary and one primary water environment. In the mill annealed condition, alloy 800 was more resistant to stress corrosion cracking than alloys 600 and 690. A low temperature anneal at 705/sup 0/C (1300/sup 0/F) improved the stress corrosion resistance of all the alloys. The greatest improvement was noted in alloy 690 where no failures were observed in any of the specimens even after annealing for only 4 hours. A test technique was developed to examine the stress corrosion behavior of a material by slowly internally pressurizing a section of tubing while the exterior was exposed to a simulated steam generator environment. Cracking of all alloys tested could be initiated in less than 20 days. The results indicate that alloy 600 and alloy 690 given a low temperature anneal at 705/sup 0/C (1300/sup 0/F) for 15 hours are more resistant to stress corrosion cracking than either mill annealed alloy 600 or mill annealed alloy 800. The degree of susceptibility of an alloy in this type of test may be dependent on pressurization rate.

Nelson, J.L.; Floreen, S.

1984-10-01

223

Conduction mechanisms in p-type Pb{sub 1-x}Eu{sub x}Te alloys in the insulator regime  

SciTech Connect

Electrical resistivity measurements were performed on p-type Pb{sub 1-x}Eu{sub x}Te films with Eu content x = 4%, 5%, 6%, 8%, and 9%. The well-known metal-insulator transition that occurs around 5% at room temperature due to the introduction of Eu is observed, and we used the differential activation energy method to study the conduction mechanisms present in these samples. In the insulator regime (x > 6%), we found that band conduction is the dominating conduction mechanism for high temperatures with carriers excitation between the valence band and the 4f levels originated from the Eu atoms. We also verified that mix conduction dominates the low temperatures region. Samples with x = 4% and 5% present a temperature dependent metal insulator transition and we found that this dependence can be related to the relation between the thermal energy k{sub B}T and the activation energy {Delta}{epsilon}{sub a}. The physical description obtained through the activation energy analysis gives a new insight about the conduction mechanisms in insulating p-type Pb{sub 1-x}Eu{sub x}Te films and also shed some light over the influence of the 4f levels on the transport process in the insulator region.

Peres, M. L.; Rubinger, R. M.; Ribeiro, L. H.; Rubinger, C. P. L. [Departamento de Fisica e Quimica, Instituto de Ciencias Exatas, Universidade Federal de Itajuba, Itajuba, PB 50, MG CEP 37500-903 (Brazil); Ribeiro, G. M. [Departamento de Fisica, ICEx, Universidade Federal de Minas Gerais, Belo Horizonte, PB 702, MG CEP 30123-970 (Brazil); Chitta, V. A. [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo, PB 66318, SP CEP 05315-970 (Brazil); Rappl, P. H. O.; Abramof, E. [Laboratorio Associado de Sensores e Materiais, Instituto Nacional de Pesquisas Espaciais, Sao Jose dos Campos, PB 515, SP CEP 12201-970 (Brazil)

2012-06-15

224

Production and welding technology of some high-temperature nickel alloys in relation to their properties  

SciTech Connect

The most effective matching of alloys to the needs of advanced high-temperature gas-cooled reactors requires not only a knowledge of material properties, but also some understanding of the inherent general characteristics of this type of alloy. Some of the characteristic features of high-temperature nickel-based alloys are explored and general guidelines offered for their most effective use. Examples are drawn from three commercial materials: Inconel alloy 617, Incoloy alloy 800H, and Nimonic alloy 86. Such items as hot and cold working, heat treating, welding, and mechanical properties are considered.

Bassford, T.H.; Hosier, J.C.

1984-07-01

225

Creep Resistant Zinc Alloy  

SciTech Connect

This report covers the development of Hot Chamber Die Castable Zinc Alloys with High Creep Strengths. This project commenced in 2000, with the primary objective of developing a hot chamber zinc die-casting alloy, capable of satisfactory service at 140 C. The core objectives of the development program were to: (1) fill in missing alloy data areas and develop a more complete empirical model of the influence of alloy composition on creep strength and other selected properties, and (2) based on the results from this model, examine promising alloy composition areas, for further development and for meeting the property combination targets, with the view to designing an optimized alloy composition. The target properties identified by ILZRO for an improved creep resistant zinc die-casting alloy were identified as follows: (1) temperature capability of 1470 C; (2) creep stress of 31 MPa (4500 psi); (3) exposure time of 1000 hours; and (4) maximum creep elongation under these conditions of 1%. The project was broadly divided into three tasks: (1) Task 1--General and Modeling, covering Experimental design of a first batch of alloys, alloy preparation and characterization. (2) Task 2--Refinement and Optimization, covering Experimental design of a second batch of alloys. (3) Task 3--Creep Testing and Technology transfer, covering the finalization of testing and the transfer of technology to the Zinc industry should have at least one improved alloy result from this work.

Frank E. Goodwin

2002-12-31

226

TiNi Base Alloy Shape Memory Enhancement through Thermal and Mechanical Processing.  

National Technical Information Service (NTIS)

A process for improving the shape change memory properties of a titanium-nickel base alloy by: (1) heat treating the alloy to convert the TiNi phase to CsCl (B2) type crystal structure, (2) cold working the alloy to increase the micro-twining, and finally...

F. E. Wang W. J. Buehler

1981-01-01

227

TiNi Base Alloy Shape Memory Enhancement through Thermal and Mechanical Processing.  

National Technical Information Service (NTIS)

A process for improving the shape change memory properties of a titanium-nickel base alloy by (1) heat treating the alloy to convert the TiNi phase to CsCl (B2)-type crystal structure, (2) cold working the alloy to increase the micro-twinning, and finally...

F. E. Wang W. J. Buehler

1980-01-01

228

Weldability of High Alloys  

SciTech Connect

The purpose of this study was to investigate the effect of silicon and iron on the weldability of HAYNES HR-160{reg_sign} alloy. HR-I60 alloy is a solid solution strengthened Ni-Co-Cr-Si alloy. The alloy is designed to resist corrosion in sulfidizing and other aggressive high temperature environments. Silicon is added ({approx}2.75%) to promote the formation of a protective oxide scale in environments with low oxygen activity. HR-160 alloy has found applications in waste incinerators, calciners, pulp and paper recovery boilers, coal gasification systems, and fluidized bed combustion systems. HR-160 alloy has been successfully used in a wide range of welded applications. However, the alloy can be susceptible to solidification cracking under conditions of severe restraint. A previous study by DuPont, et al. [1] showed that silicon promoted solidification cracking in the commercial alloy. In earlier work conducted at Haynes, and also from published work by DuPont et al., it was recognized that silicon segregates to the terminal liquid, creating low melting point liquid films on solidification grain boundaries. Solidification cracking has been encountered when using the alloy as a weld overlay on steel, and when joining HR-160 plate in a thickness greater than19 millimeters (0.75 inches) with matching filler metal. The effect of silicon on the weldability of HR-160 alloy has been well documented, but the effect of iron is not well understood. Prior experience at Haynes has indicated that iron may be detrimental to the solidification cracking resistance of the alloy. Iron does not segregate to the terminal solidification product in nickel-base alloys, as does silicon [2], but iron may have an indirect or interactive influence on weldability. A set of alloys covering a range of silicon and iron contents was prepared and characterized to better understand the welding metallurgy of HR-160 alloy.

Maroef, I

2003-01-22

229

Creep crack growth behavior of several structural alloys  

NASA Astrophysics Data System (ADS)

Creep crack growth behavior of several high temperature alloys, Inconel 600, Inconel 625, Inconel X-750, Hastelloy X, Nimonic PE-16, Incoloy 800, and Haynes 25 (HS-25) was examined at 540, 650, 760, and 870 °C. Crack growth rates were analyzed in terms of both linear elastic stress intensity factor and J*-integral parameter. Among the alloys Inconel 600 and Hastelloy X did not show any observable crack growth. Instead, they deformed at a rapid rate resulting in severe blunting of the crack tip. The other alloys, Inconel 625, Inconel X-750, Incoloy 800, HS-25, and PE-16 showed crack growth at one or two temperatures and deformed continuously at other temperatures. Crack growth rates of the above alloys in terms ofJ* parameter were compared with the growth rates of other alloys published in the literature. Alloys such as Inconel X-750, Alloy 718, and IN-100 show very high growth rates as a result of their sensitivity to an air environment. Based on detailed fracture surface analysis, it is proposed that creep crack growth occurs by the nucleation and growth of wedge-type cracks at triple point junctions due to grain boundary sliding or by the formation and growth of cavities at the boundaries. Crack growth in the above alloys occurs only in some critical range of strain rates or temperatures. Since the service conditions for these alloys usually fall within this critical range, knowledge and understanding of creep crack growth behavior of the structural alloys are important.

Sadananda, K.; Shahinian, P.

1983-07-01

230

Oxidation and sulfidation resistant alloys with silicon additions  

SciTech Connect

The Albany Research Center (ARC) has considerable experience in developing lean chromium, austenitic stainless steels with improved high temperature oxidation resistance. Using basic alloy design principles, a baseline composition of Fe-16Cr-16Ni-2Mn-1Mo alloys with Si and Al addition at a maximum of 5 weight percent was selected for potential application at temperatures above 700ºC for supercritical and ultra-supercritical power plant application. The alloys were fully austenitic. Cyclic oxidation tests in air for 1000 hours were carried out on alloys with Si only or combined Si and Al additions in the temperature range 700ºC to 800ºC. Oxidation resistances of alloys with Si only additions were outstanding, particularly at 800ºC (i.e., these alloys possessed weight gains 4 times less than a standard type-304 alloy). In addition, Si alloys pre-oxidized at 800ºC, showed a zero weight gain in subsequent testing for 1000 hours at 700ºC. Similar improvements were observed for Si only alloy after H2S exposure at 700ºC compared with type 304 stainless steel. SEM and ESCA analysis of the oxide films and base material at the oxide/base metal interface were conducted to study potential rate controlling mechanisms at ARC. Depth profile analysis and element concentration profiles (argon ion etching/x-ray photoelectron spectroscopy) were conducted on oxidized specimens and base material at the National Energy Technology Laboratory.

Dunning, John S.; Alman, David E.; Poston, J.A., Jr. (NETL); Siriwardane, R. (NETL)

2003-01-01

231

[Titanium-alloy vs. CoCr-alloy in removable partial dentures--a clinical study].  

PubMed

Different types of titanium-alloys instead of CoCr-alloys have been tested as material for the framework of removable partial dentures (RPD). Adequate casting and processing techniques have been developed which enable to fabricate frameworks of complex designs and the problem limits porosity. This opened new possibilities for the use of titanium-alloys with improved properties (E-module). The aim of this study was to summarise the use of titanium in removable prosthodontics and to evaluate prospectively the use of the Ti6A17Nb-alloy for RPDs in a small group of patients. Two identically designed RPDs from CoCr-alloy (remanium GM 800+) and Ti6A17Nb-alloy (girotan L) were produced for ten patients. They had to wear each RPD during six months, first the CoCr-RPD and then the Ti6A17Nb-RPD. A questionnaire (visual analogue scale = VAS) was completed by the patients after one, three and six months of function for each RPD. Prosthetic complications and service needed were recorded. After the end of the entire observation period of twelve months, the patients remained with the Ti6A17Nb-RPD and answered the questionnaire after another six months. All parameters regarding the design of the RPDs were positively estimated by the dentist. Minimal, not significant differences were noted by the patients concerning comfort, stability and retention (VAS). Clinically, no differences in technical aspects or regarding biological complications were observed after six-months periods. The Ti6A17Nb-alloy (girotan L) for the framework of RPDs was judged by patients and professionals to be equivalent to RPDs made from CoCr-alloy. No differences in material aspects could objectively be observed. The Ti6A17Nb-alloy can be beneficial for patients with allergies or incompatibility with one or several components of the CoCr-alloy. PMID:19066155

Katsoulis, Joannis; Fischer, Jens; Huber, Sandra; Balmer, Sacha; Mericske-Stern, Regina

2008-01-01

232

Effect of Pd or Au addition on age-hardening in AgMn-based alloys  

Microsoft Academic Search

Objective: The objective of this research was to characterize the age-hardening behavior of AgMn alloys modified with Au or Pd. These alloys are being studied as possible alternatives to Type III dental alloys.Methods: The age-hardening reactions in Ag-37at% Mn alloys with 5at% Au or Pd were investigated by optical microscopy, electrical resistivity, X-ray diffraction and hardness tests.Results: Optical microscopy showed

I Kawashima; H Ohno; N. K Sarkar

2000-01-01

233

46 CFR 54.25-15 - Low temperature operation-high alloy steels (modifies UHA-23(b) and UHA-51).  

Code of Federal Regulations, 2010 CFR

...Carbon, Alloy, and Heat Treated Steels § 54.25-15 Low temperature operationâhigh alloy steels (modifies UHA-23(b) and UHA-51...than 0.10 percent) austenitic stainless steel type, produced according...

2009-10-01

234

46 CFR 54.25-15 - Low temperature operation-high alloy steels (modifies UHA-23(b) and UHA-51).  

Code of Federal Regulations, 2010 CFR

...Carbon, Alloy, and Heat Treated Steels § 54.25-15 Low temperature operationâhigh alloy steels (modifies UHA-23(b) and UHA-51...than 0.10 percent) austenitic stainless steel type, produced according...

2010-10-01

235

Photoelectron spectroscopic study on the electronic structures of the dental gold alloys and their interaction with L-cysteine  

SciTech Connect

The valence electronic structures of the dental gold alloys, type 1, type 3, and K14, and their interaction with L-cysteine have been studied by ultraviolet photoelectron spectroscopy with synchrotron radiation. It was found that the electronic structures of the type-1 and type-3 dental alloys are similar to that of polycrystalline Au, while that of the K14 dental alloy is much affected by Cu. The peak shift and the change in shape due to alloying are observed in all the dental alloys. It is suggested that the new peak observed around 2 eV for the L-cysteine thin films on all the dental alloys may be due to the bonding of S 3sp orbitals with the dental alloy surfaces, and the Cu-S bond, as well as the Au-S and Au-O bonds, may cause the change in the electronic structure of the L-cysteine on the alloys.

Ogawa, Koji; Takahashi, Kazutoshi; Azuma, Junpei; Kamada, Masao [Synchrotron Light Application Center, Saga University, 1 Honjo, Saga, Saga 840-8502 (Japan); Tsujibayashi, Toru; Ichimiya, Masayoshi [Department of Physics, Osaka Dental University, 8-1 Kuzuha-hanazono, Hirakata, Osaka 573-1121 (Japan); Fujimoto, Hitoshi [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto, Kumamoto 860-8555 (Japan); Sumimoto, Michinori [Graduate School of Science and Engineering, Yamaguchi University, 2-16-1 Tokiwadai, Ube, Yamaguchi 755-8611 (Japan)

2011-11-15

236

Investment Casting of Columbium Alloys.  

National Technical Information Service (NTIS)

The state of the art of columbium alloy investment castings has been advanced. In addition to demonstration of castability of four different alloys, the cast material itself has been characterized with respect to microstructure, alloy segregation, weldabi...

J. R. Humphrey A. I. Niravath

1975-01-01

237

Electrical discharge surface alloying  

Microsoft Academic Search

This paper details the electrical discharge surface alloying\\/modification of ?-TiAl (Ti–46.5Al–4(Cr, Nb, Ta, B)) and ?\\/? Ti alloy (Ti–6Al–4V) sheet (1mm thick) during wire cutting using deionised water dielectric with nickel and copper wires. In addition, topography, microstructure and wear test data are given for a 2% Cr steel mill roll material textured\\/alloyed using partially sintered powder metallurgy (PM) hardmetal

H. G Lee; J Simao; D. K Aspinwall; R. C Dewes; W Voice

2004-01-01

238

Low activation ferritic alloys  

DOEpatents

Low activation ferritic alloys, specifically bainitic and martensitic stainless steels, are described for use in the production of structural components for nuclear fusion reactors. They are designed specifically to achieve low activation characteristics suitable for efficient waste disposal. The alloys essentially exclude molybdenum, nickel, nitrogen and niobium. Strength is achieved by substituting vanadium, tungsten, and/or tantalum in place of the usual molybdenum content in such alloys.

Gelles, D.S.; Ghoniem, N.M.; Powell, R.W.

1985-02-07

239

NICKEL-BASE ALLOY  

DOEpatents

A nickel-base alloy was developed which is particularly useful for the containment of molten fluoride salts in reactors. The alloy is resistant to both salt corrosion and oxidation and may be used at temperatures as high as 1800 deg F. Basically, the alloy consists of 15 to 22 wt.% molybdenum, a small amount of carbon, and 6 to 8 wt.% chromium, the balance being nickel. Up to 4 wt.% of tungsten, tantalum, vanadium, or niobium may be added to strengthen the alloy.

Inouye, H.; Manly, W.D.; Roche, T.K.

1960-01-19

240

Amorphous alloys and superconductivity  

SciTech Connect

Theoretical aspects and experimental results concerning transition temperatures, coupling constants, critical field, critical current density and pressure dependence of T /sub c/ of amorphous alloys are discussed.

Luscher, E.; Fritsch, G.

1984-09-01

241

Laser surface alloying of coins for authenticity  

NASA Astrophysics Data System (ADS)

This paper presents an exploratory investigation on verifying the feasibility of using a laser surface alloying technique to produce designs in the surface of coinage blanks. The specific aim of the work concerns the production of design features in coins that are difficult to produce by other techniques and which hence act as a barrier to forgery and features which permit automatic recognition in vending machines, particularly as a means of establishing the authenticity of the coins. Coins in many countries today are commonly manufactured from metal composites, where one substrate metal or alloy is coated with another by a process of electrodeposition or by mechanical bonding. The technique here described entails the use of a high power CO2 laser to bring about localized melting of the two layers. Visible distinction between alloyed and unalloyed regions or difference in other physical properties such as conductivity or magnetic properties can be obtained. The work also involved a fundamental study of the influence of the thermal properties of the materials on the CO2 laser alloying process. It was found that the thermal properties such as thermal conductivity of the substrate materials and the difference of the melting points between the coating layer and the substrate materials played an important role in the process. Laser control variables required for localized alloying for different substrate and coatings types were determined. The influence of both thermal properties and laser control variables on alloy type and alloy depth were investigated. Initial work on coin validation showed promising results of an automatic recognition of laser treated coins.

Liu, Zhu; Watkins, Kenneth G.; Steen, William M.; Hatherley, P. G.

1997-08-01

242

Trends in battery alloy demand from a European perspective  

NASA Astrophysics Data System (ADS)

This paper discusses the demand in Europe for lead battery alloys by volume and type. The technical implications of the required changes in specification and quality are detailed from a lead-producer's perspective.

Woodcock, C.; Lurshay, A.

1994-02-01

243

Evaluation of austenitic alloys 304L and 316L and alloy 825 under tuff-repository conditions  

SciTech Connect

Primary concerns over use of types 304L and 316L are for chloride- induced stress-corrosion cracking (SCC) and weld microstructure stability. Possibly alloy 825 will be a more suitable candidate. (DLC)

Kass, J.

1989-05-01

244

Corrosion of alloy steels in oil field fluids  

SciTech Connect

Laboratory and field tests have been conducted on two low alloy and two higher alloy steels at a range of brine salinities and sulfide contents typical of oil well production fluids. AISI types 4130 and 4340 show the same behavior in these fluids as mild steel. AISI type 410 stainless steel and 9% chromium - 1% molybdenum steel corrode at rates as great as that of mild steel at higher chloride or sulfide concentrations. Special corrosion inhibitors are required for higher alloy steels when they are exposed to these conditions.

Martin, R.L.

1987-01-01

245

Feedback compensation of shape memory alloy hysteresis  

Microsoft Academic Search

Traditionally, actuators have been large and heavy (eg., motors). Because of their physical size and structure, they increase the size and weight of the entire system. In many applications, it is desirable to find an alternative to these conventional type of actuators. Shape memory alloy (SMA) has been considered as an actuator for applications that require large force and displacement.

Carrie A. Dickinson

1997-01-01

246

FACTORS AFFECTING CORROSION RESISTANCE OF RECUPERATOR ALLOYS  

Microsoft Academic Search

As microturbine recuperators are needed to operate at higher temperatures in order to achieve higher engine operating efficiencies, a recurring problem encountered is a severe degradation in environ- mental resistance of type 347 stainless steel. Above 600°C, stainless steels can experience accelerated attack caused by water vapor, which is often present as a combustion product. Nickel-base alloys are less susceptible

Bruce A. Pint; Raphaëlle Peraldi

2003-01-01

247

Effects of Li concentration and a Mg addition on serrated flow in Al-Li alloys  

SciTech Connect

Serrated flow phenomena have been reported in a variety of precipitation-strengthened aluminum alloys. In the particular case of precipitation-strengthened Al-Li alloys, serrated flow effects of similar character have been reported in binary Al-Li alloys and in commercial-type Al-Li alloys containing multiple alloying elements. Observations of serrated flow in binary Al-Li alloys indicate that the presence of Li alone is sufficient to produce serrated flow. Aging time has been used to probe the mechanisms that cause serrated flow in individual Al-Li alloys, and several investigators have noted that serrated flow disappears when Al-Li alloys are aged to peak strength or overaged. Much of the available experimental evidence supports dislocation-[delta][prime] interactions as the cause of serrated flow in Al-Li alloys, rather than dislocation-solute atom interactions to which serrated flow phenomena are traditionally attributed. Additional support for this conclusion could be provided by comparison of stress-strain curves for a solid solution Al-Li binary alloy of the same composition as the matrix phase of a precipitation-strengthened Al-Li binary alloy. The purpose of the present paper is to show stress--strain curves for Al-1.38Li, Al-1.80Li and Al-1.39Li-1.0Mg alloys, and to interpret the results in terms of the interactions proposed to account for serrated flow in Al-Li alloys.

Zambo, S.J.; Wert, J.A. (Univ. of Virginia, Charlottesville, VA (United States). Dept. of Materials Science and Engineering)

1993-12-15

248

The effect of selected alloying element additions on properties of Mg-based alloy as bioimplants: A literature review  

NASA Astrophysics Data System (ADS)

This review investigates the current application limitations of Mg and Mg alloys. The key issues hindering the application of biodegradable Mg alloys as implants are their fast degradation rate and biological consideration. We have discussed the effect of some selected alloying element additions on the properties of the Mg-based alloy, especially the nutrient elements in human (Zn, Mn, Ca, Sr). Different grain sizes, phase constituents and distributions consequently influence the mechanical properties of the Mg alloys. Solution strengthening and precipitation strengthening are enhanced by the addition of alloying elements, generally improving the mechanical properties. Besides, the hot working process can also improve the mechanical properties. Combination of different processing steps is suggested to be adopted in the fabrication of Mg-based alloys. Corrosion properties of these Mg-based alloys have been measured in vitro and in vivo. The degradation mechanism is also discussed in terms of corrosion types, rates, byproducts and response of the surrounding tissues. Moreover, the clinical response and requirements of degradable implants are presented, especially for the nutrient elements (Ca, Mn, Zn, Sr). This review provides information related to different Mg alloying elements and presents the promising candidates for an ideal implant.

Zhang, Li-Nan; Hou, Zeng-Tao; Ye, Xin; Xu, Zhao-Bin; Bai, Xue-Ling; Shang, Peng

2013-09-01

249

Physical and welding metallurgy of Gd-enriched austenitic alloys for spent nuclear fuel applications. Part II, nickel base alloys.  

SciTech Connect

The physical and welding a metallurgy of gadolinium- (Gd-) enriched Ni-based alloys has been examined using a combination of differential thermal analysis, hot ductility testing. Varestraint testing, and various microstructural characterization techniques. Three different matrix compositions were chosen that were similar to commercial Ni-Cr-Mo base alloys (UNS N06455, N06022, and N06059). A ternary Ni-Cr-Gd alloy was also examined. The Gd level of each alloy was {approx}2 wt-%. All the alloys initiated solidification by formation of primary austenite and terminated solidification by a Liquid {gamma} + Ni{sub 5}Gd eutectic-type reaction at {approx}1270 C. The solidification temperature ranges of the alloys varied from {approx}100 to 130 C (depending on alloy composition). This is a substantial reduction compared to the solidification temperature range to Gd-enriched stainless steels (360 to 400 C) that terminate solidification by a peritectic reaction at {approx}1060 C. The higher-temperature eutectic reaction that occurs in the Ni-based alloys is accompanied by significant improvements in hot ductility and solidification cracking resistance. The results of this research demonstrate that Gd-enriched Ni-based alloys are excellent candidate materials for nuclear criticality control in spent nuclear fuel storage applications that require production and fabrication of large amounts of material through conventional ingot metallurgy and fusion welding techniques.

Mizia, Ronald E. (Idaho National Engineering and Environmental Laboratory, Idaho Falls, ID); Michael, Joseph Richard; Williams, David Brian (Lehigh University, Bethlehem, PA); Dupont, John Neuman (Lehigh University, Bethlehem, PA); Robino, Charles Victor

2004-06-01

250

Ductile transplutonium metal alloys  

DOEpatents

Alloys of Ce with transplutonium metals such as Am, Cm, Bk and Cf have properties making them highly suitable as souces of the transplutonium element, e.g., for use in radiation detector technology or as radiation sources. The alloys are ductile, homogeneous, easy to prepare and have a fairly high density.

Conner, W.V.

1981-10-09

251

Cesium iodide alloys  

DOEpatents

A transparent, strong CsI alloy is described having additions of monovalent iodides. Although the preferred iodide is AgI, RbI and CuI additions also contribute to an improved polycrystalline CsI alloy with outstanding multispectral infrared transmittance properties. 6 figs.

Kim, H.E.; Moorhead, A.J.

1992-12-15

252

Spectra of Ternary Alloys  

Microsoft Academic Search

The vibrational frequency-dsitribution spectra of the random one-dimensional ternary alloy AcB1-cC are accurately predicted for the first time by a statistical theory of small clusters embedded in a coherent-potential-approximation effective medium. The theory can be applied practically to real three-dimensional alloys.

Charles W. Myles; John D. Dow

1979-01-01

253

Neutron Absorbing Alloys  

DOEpatents

The present invention is drawn to new classes of advanced neutron absorbing structural materials for use in spent nuclear fuel applications requiring structural strength, weldability, and long term corrosion resistance. Particularly, an austenitic stainless steel alloy containing gadolinium and less than 5% of a ferrite content is disclosed. Additionally, a nickel-based alloy containing gadolinium and greater than 50% nickel is also disclosed.

Mizia, Ronald E. (Idaho Falls, ID); Shaber, Eric L. (Idaho Falls, ID); DuPont, John N. (Whitehall, PA); Robino, Charles V. (Albuquerque, NM); Williams, David B. (Bethlehem, PA)

2004-05-04

254

Fracture toughness investigations of tungsten alloys and SPD tungsten alloys  

Microsoft Academic Search

Three different tungsten alloys (pure W, a lanthanum-oxide dispersion strengthened W-alloy – WL10 and a potassium doped tungsten alloy – WVM) in different fabrication conditions (sintered and rolled rods) were tested to characterize their fracture behaviour at different temperatures (from ?196 to 800°C). Additionally severe plastic deformed tungsten alloys were produced. It is shown that an ultra fine grained microstructure

M. Faleschini; H. Kreuzer; D. Kiener; R. Pippan

2007-01-01

255

Investigation on mechanical alloying process for vanadium alloys  

NASA Astrophysics Data System (ADS)

Mechanical alloying (MA) is an efficient approach for fabricating particle-dispersion alloys, and has recently been introduced to strengthen structural materials including vanadium alloys for fusion application. Dissolution behavior of the alloying elements is a key issue for optimizing MA in fabricating particle-dispersion vanadium alloys. This paper studies the MA process for V-4Cr-4Ti alloys with Y addition. The result shows that, in V matrix, the dissolution rate of Y is higher than that of Cr, and the dissolution rate of Cr is higher than that of Ti. In addition, dissolution of milling ball material and dispersion particles can harden the MA-fabricated alloy.

Zheng, P. F.; Nagasaka, T.; Muroga, T.; Chen, J. M.

2013-11-01

256

Plating on stainless steel alloys  

SciTech Connect

Quantitative adhesion data are presented for a variety of electroplated stainless steel type alloys. Results show that excellent adhesion can be obtained by using a Wood's nickel strike or a sulfamate nickel strike prior to final plating. Specimens plated after Wood's nickel striking failed in the deposit rather than at the interface between the substrate and the coating. Flyer plate quantitative tests showed that use of anodic treatment in sulfuric acid prior to Wood's nickel striking even further improved adhesion. In contrast activation of stainless steels by immersion or cathodic treatment in hydrochloric acid resulted in very reduced bond strengths with failure always occurring at the interface between the coating and substrate.

Dini, J.W.; Johnson, H.R.

1981-09-11

257

The transient oxidation of alloys  

Microsoft Academic Search

The pre-steady-state oxidation of a wide range of binary alloys of practical importance, in 1 atm oxygen at 600° C, is discussed in terms of the main determining parameters, namely the free energies of formation and growth rates of the component and complex oxides, the bulk alloy composition, the alloy interdiffusion coefficient, the oxygen solubility and diffusivity in the alloy,

B. Chattopadhyay; G. C. Wood

1970-01-01

258

Near-Surface Deformed Layers on Rolled Aluminum Alloys  

NASA Astrophysics Data System (ADS)

Near-surface deformed layers, which are characterized by nano-sized fine grains, are generated in aluminum alloys by hot and cold rolling. During the rolling processes, the alloy surface and near-surface regions experience a high level of shear deformation that results in significant microstructure refinement, leading to formation of near-surface deformed layers with microstructures different from that of the underlying bulk alloy. Two types of near-surface deformed layers are observed. Type A is characterized by fine grains with grain boundaries decorated by oxide particles; type B is characterized also by fine grains but with the grain boundaries free of oxide particles. The high levels of shear deformation result in dynamic recrystallization. Together with mechanical alloying, this is responsible for the formation of the near-surface deformed layer. Furthermore, the structure in the near-surface deformed layer can survive the typical annealing process particularly if the grain boundaries are pinned by oxide particles.

Zhou, X.; Liu, Y.; Thompson, G. E.; Scamans, G. M.; Skeldon, P.; Hunter, J. A.

2011-05-01

259

Quasicrystal structure of rapidly solidified Ti-Ni-based alloys  

NASA Astrophysics Data System (ADS)

Rapidly solidified Ti56Ni23Fe5Si16 has been prepared by quenching from the melt onto a single roller. X-ray diffraction measurements showed the alloy to be single phased with a pattern characteristic of the icosahedral structure. Diffraction peaks were indexed using scattering vectors described by a set of icosahedral basis vectors. The ratio of the quasilattice constant to the mean interatomic spacing for the corresponding crystalline alloy, Ti2Ni, is 1.82. This is intermediate between the values for Al-Mn-Si type alloys, 1.65, and for Al-Zn-Mg type alloys, 2.00, and suggests a new type of icosahedral structure. The present diffraction intensities, along with a high Fe site symmetry previously reported from Mössbauer studies suggests a decoration of Penrose rhombehedra with Fe and Ni at the vertices and Ti at the edges.

Dunlap, R. A.; O'Handley, R. C.; McHenry, M. E.; Chatterjee, R.

1988-05-01

260

Synthesis and Characterization of Magnesium-Alloyed Hematite Thin Films  

NASA Astrophysics Data System (ADS)

We have synthesized pure and Mg-alloyed hematite thin films on F-doped, SnO2-coated glass substrates by radiofrequency magnetron cosputtering of iron oxide with and without MgO sources in mixed Ar/O2 and mixed N2/O2 ambient. We found that hematite films deposited in N2/O2 ambient exhibited much poorer crystallinity than those deposited in Ar/O2 ambient. We determined that Mg alloying led to increased crystallinity and bandgap. Furthermore, we found that Mg alloying inverted the type of conductivity of the thin films: pure hematite thin films exhibited n-type conductivity, whereas Mg-alloyed hematite thin films exhibited p-type conductivity.

Tang, Houwen; Matin, M. A.; Wang, Heli; Al-Jassim, Mowafak; Turner, John; Yan, Yanfa

2012-11-01

261

Effect of rapid solidification and alloying addition on lattice distortion and atomic ordering in L1 0 tial alloys and their ternary alloys  

Microsoft Academic Search

Binary and ternary L10 type titanium alloys were rapidly quenched into thin foils by the hammer-anvil quenching technique. The nominal alloy compositions\\u000a include Ti1-xAlx and (Ti1-xAlx)100-@#@ yMy, wherex = 0.5 to 0.6; y= 1 to 4; and M is V, Cr, Mn, Fe, Co, Ni, and Ge. Lattice parameters of Ll0 phases in these alloys were studied by X-ray diffractometer

Dinko Vujic; Zhixian Li; Sung H. Whang

1988-01-01

262

Turning of gamma TiAl Intermetallic alloys  

NASA Astrophysics Data System (ADS)

In the present work the turning of two different aluminium titanium of the so-called gamma TiAl (or titanium aluminides) is presented. These alloys are solidified in gamma phase, being this a uncommon case in the industrial materials. This kind of titanium alloy presents improved mechanical properties even at high temperatures, the ratio between resistance and weight and resistance and low corrosion is greater than the more known alfa-beta type titanium alloys. However an absolute lack of recommendation for machining alters the material production is delaying a lot the use of gamma TiAl in car and aeronautical applications. This work presents the main results of a long testing program on three alloys, with different application fields. The main conclusion is that they are difficult-to-cut materials, even harder to machining that titanium alloys.

Beranoagirre, A.; López de Lacalle, L. N.

2012-04-01

263

The complex structure of liquid Cu6Sn5 alloy  

NASA Astrophysics Data System (ADS)

By applying ab initio molecular dynamics simulation to liquid Cu6Sn5 alloy, the hetero-coordination tendency is discovered by Bathia-Thornton partial correlation functions and a chemical short-range parameter. However the local structural environment of Sn in l-Cu6Sn5 alloy resembles that of liquid Sn by Voronoi analysis. A new feature, i.e. a subpeak in between the first and second peaks, is discovered by the present method which implies that topologically disordered ?-Sn-type structural units may exist in l-Cu6Sn5 alloy. The local density states of electrons show that both Cu-Sn and Sn-Sn bonding exist in l-Cu6Sn5 alloy. This work suggests that chemical short-range order between unlike atoms and self-coordination between Sn atoms coexists in l-Cu6Sn5 alloy.

Qin, Jingyu; Liu, Hui; Gu, Tingkun; Bian, Xiufang

2009-04-01

264

Amorphous powders of Al-Hf prepared by mechanical alloying  

SciTech Connect

We synthesized amorphous Al/sub 50/Hf/sub 50/ alloy powder by mechanically alloying an equimolar mixture of crystalline powders of Al and Hf using hexane as a dispersant. We characterized the powder as a function of mechanical-alloying time by scanning electron microscopy, x-ray diffraction, and differential scanning calorimetry. Amorphous Al/sub 50/Hf/sub 50/ powder heated at 10 K s/sup /minus/1/ crystallizes polymorphously at 1003 K into orthorhombic AlHf (CrB-type structure). During mechanical alloying, some hexane decomposes and hydrogen and carbon are incorporated into the amorphous alloy powder. The hydrogen can be removed by annealing the powder by hot pressing at a temperature approximately 30 K below the crystallization temperature. The amorphous compacts have a diamond pyramidal hardness of 1025 DPH. 24 refs., 7 figs., 1 tab.

Schwarz, R.B.; Hannigan, J.W.; Sheinberg, H.; Tiainen, T.

1988-01-01

265

Two phase titanium aluminide alloy  

Microsoft Academic Search

A two-phase titanic aluminide alloy having a lamellar microstructure with little intercolony structures. The alloy can include fine particles such as boride particles at colony boundaries and\\/or grain boundary equiaxed structures. The alloy can include alloying additions such as .ltoreq.10 at % W, Nb and\\/or Mo. The alloy can be free of Cr, V, Mn, Cu and\\/or Ni and can

Seetharama C. Deevi; C. T. Liu

2001-01-01

266

THORIUM-SILICON-BERYLLIUM ALLOYS  

DOEpatents

Th, Si, anol Bt alloys where Be and Si are each present in anmounts between 0.1 and 3.5% by weight and the total weight per cent of the minor alloying elements is between 1.5 and 4.5% are discussed. These ternary alloys show increased hardness and greater resistant to aqueous corrosion than is found in pure Th, Th-Si alloys, or Th-Be alloys.

Foote, F.G.

1959-02-10

267

Electrospark alloying of the titanium alloy VT6 with tungsten-free hard alloys  

Microsoft Academic Search

The mass transfer kinetics and alloying elements distribution in a coating layer on the titanium alloy VT6 were investigated, as well as the properties of the layer after electrospark alloying with tungsten free electrodes based on the refractory compounds of titanium and zirconium nitride. !t was shown that the microhardness of the alloyed layer is 3-S times, and of the

I. A. Podchernyaeva; V. A. Lavrenko; V. I. Berezanskaya; V. P. Smirnov

1996-01-01

268

An investigation on the microstructure and tensile properties of direct squeeze cast and gravity die cast 2024 wrought Al alloy  

Microsoft Academic Search

2024 aluminum alloy, conventionally is used for wrought products. If this alloy is subjected to cast process, a large number of shrinkage porosities will be produced within its microstructure due to its long solidification range. Therefore, in order to see the effect of pressure on the microstructure and reduction of shrinkage porosities of this type of alloy, the effect of

E. Hajjari; M. Divandari

2008-01-01

269

Crystal symmetry of the pseudo-ternary T-phases in Mg-Zn-rare earth alloys  

Microsoft Academic Search

Magnesium alloys of the type Mg-Zn-RE (RE = rare earths) are of considerable interest because some cast alloys in this system exhibit significant resistance to creep at elevated temperatures. The mechanical properties of these alloys are to some extent dependent on the presence of intermetallic phases and, in particularly, upon \\

L. Y. Wei; G. L. Dunlop

1996-01-01

270

Alloy development of FeAl aluminide alloys for structural use in corrosive environments  

SciTech Connect

Objectives include adequate ductilities ([ge]10%) at ambient temperature, high-temperature strength better than stainless steels (types 304 and 316), and fabricability and weldability by conventional techniques (gas tungsten arc). The alloys should be capable of being corrosion resistant in molten nitrate salts with rates lower than other iron-base structural alloys and coating materials (such as Fe-Cr-Al alloys). Such corrosion rates should be less than 0.3 mm per year. The FeAl aluminide containing 35.8 at. % Al was selected as base composition. Preliminary studies indicate that additions of B and Zr, increase the room-temperature ductility of FeAl. Further alloying with 0.2% Mo, and/or 5% Cr, improves the creep. Our preliminary alloying effort has led to identification of the following aluminide composition with promising properties: Fe - (35 [plus minus] 2)Al - (0.3 [plus minus] 0.2)Mo - (0.2 [plus minus] 0.15)Zr - (0.3 [plus minus] 0.2)B- up to 5Cr, at. %. However, this composition is likely to be modified in future work to improve the weldability of the alloy. The FeAl alloy FA-362 (Fe-35.8% Al-0.2% Mo-0.05% Zr-0.24% B) produced by hot extrusion at 900C showed a tensile ductility of more than 10% at room temperature and a creep rupture life longer than unalloyed FeAl by more than an order of magnitude at 593C at 138 MPa. Melting and processing of scaled-up heats of selected FeAl alloys are described. Forging, extruding, and hot-rolling processes for the scale-up heats are also described.

Liu, C.T.; Sikka, V.K.; McKamey, C.G.

1993-02-01

271

Alloy development of FeAl aluminide alloys for structural use in corrosive environments  

SciTech Connect

Objectives include adequate ductilities ({ge}10%) at ambient temperature, high-temperature strength better than stainless steels (types 304 and 316), and fabricability and weldability by conventional techniques (gas tungsten arc). The alloys should be capable of being corrosion resistant in molten nitrate salts with rates lower than other iron-base structural alloys and coating materials (such as Fe-Cr-Al alloys). Such corrosion rates should be less than 0.3 mm per year. The FeAl aluminide containing 35.8 at. % Al was selected as base composition. Preliminary studies indicate that additions of B and Zr, increase the room-temperature ductility of FeAl. Further alloying with 0.2% Mo, and/or 5% Cr, improves the creep. Our preliminary alloying effort has led to identification of the following aluminide composition with promising properties: Fe - (35 {plus_minus} 2)Al - (0.3 {plus_minus} 0.2)Mo - (0.2 {plus_minus} 0.15)Zr - (0.3 {plus_minus} 0.2)B- up to 5Cr, at. %. However, this composition is likely to be modified in future work to improve the weldability of the alloy. The FeAl alloy FA-362 (Fe-35.8% Al-0.2% Mo-0.05% Zr-0.24% B) produced by hot extrusion at 900C showed a tensile ductility of more than 10% at room temperature and a creep rupture life longer than unalloyed FeAl by more than an order of magnitude at 593C at 138 MPa. Melting and processing of scaled-up heats of selected FeAl alloys are described. Forging, extruding, and hot-rolling processes for the scale-up heats are also described.

Liu, C.T.; Sikka, V.K.; McKamey, C.G.

1993-02-01

272

Analysis of niobium alloys.  

PubMed

An ion-exchange method was applied to the analysis of synthetic mixtures representing various niobium-base alloys. The alloying elements which were separated and determined include vanadium, zirconium, hafnium, titanium, molybdenum, tungsten and tantalum. Mixtures containing zirconium or hafnium, tungsten, tantalum and niobium were separated by means of a single short column. Coupled columns were employed for the resolution of mixtures containing vanadium, zirconium or titanium, molybdenum, tungsten and niobium. The separation procedures and the methods employed for the determination of the alloying elements in their separate fractions are described. PMID:18960385

Ferraro, T A

1968-09-01

273

Pitting, galvanic, and long-term corrosion studies on candidate container alloys for the Tuff Repository  

SciTech Connect

Contest Columbus Technologies, Inc. (CC Technologies) investigated the long-term performance of container materials for high-level radioactive waste packages as part of the information needed by the Nuclear Regulatory Commission to assess the Department of Energy's application to construct a geologic repository for the high-level radioactive waste. The scope of work focused on the Tuff Repository and employed short-term techniques, such as electrochemical and mechanical techniques to examine a wide range of possible failure modes. Two classes of alloys were evaluated for use as container materials for the Tuff Repository; Fe-Cr-Ni alloys and copper-base alloys. The candidate Fe-Cr-Ni alloys were Type 304L Stainless Steel (Alloy 304L) and Incoloy Alloy 825 (Alloy 825). The candidate copper-base alloys were CDA 102 Copper (Alloy CDA 102) and CDA 715 Copper-3D Nickel (Alloy CDA 715). The corrosion testing was performed in a simulated J-13 well water and in solutions selected from an experimental matrix from Task 2 of the program. This report summarizes the results of Task 4 (Pitting Studies), Task 6 (Other Failure Modes) and Task 7 (Long-Term Exposures) of the program. Pit-initiation studies, performed in Task 4, focused on anomalous Cyclic Potentiodynamic Polarization (CPP) behavior of the copper-base alloys reported in Task 2 of the program. Pit propagation studies were performed on Alloy CDA 102 in Task A of the program. Two types of galvanic corrosion studies were performed in Task 6 of the program; thermogalvanic couples and borehole linear-container interactions. In the thermogalvanic couples tests, the effect of temperature variation on the surface of the container on acceleration of corrosion was evaluated for two alloys; Alloy CDA 102 and Alloy 304L. Long-term immersion tests were conducted in Task 7 of the program.

Beavers, J.A.; Thompson, N.G.; Durr, C.L. (Cortest Columbus Technologies, OH (United States))

1992-01-01

274

Pitting, galvanic, and long-term corrosion studies on candidate container alloys for the Tuff Repository  

SciTech Connect

Contest Columbus Technologies, Inc. (CC Technologies) investigated the long-term performance of container materials for high-level radioactive waste packages as part of the information needed by the Nuclear Regulatory Commission to assess the Department of Energy`s application to construct a geologic repository for the high-level radioactive waste. The scope of work focused on the Tuff Repository and employed short-term techniques, such as electrochemical and mechanical techniques to examine a wide range of possible failure modes. Two classes of alloys were evaluated for use as container materials for the Tuff Repository; Fe-Cr-Ni alloys and copper-base alloys. The candidate Fe-Cr-Ni alloys were Type 304L Stainless Steel (Alloy 304L) and Incoloy Alloy 825 (Alloy 825). The candidate copper-base alloys were CDA 102 Copper (Alloy CDA 102) and CDA 715 Copper-3D Nickel (Alloy CDA 715). The corrosion testing was performed in a simulated J-13 well water and in solutions selected from an experimental matrix from Task 2 of the program. This report summarizes the results of Task 4 (Pitting Studies), Task 6 (Other Failure Modes) and Task 7 (Long-Term Exposures) of the program. Pit-initiation studies, performed in Task 4, focused on anomalous Cyclic Potentiodynamic Polarization (CPP) behavior of the copper-base alloys reported in Task 2 of the program. Pit propagation studies were performed on Alloy CDA 102 in Task A of the program. Two types of galvanic corrosion studies were performed in Task 6 of the program; thermogalvanic couples and borehole linear-container interactions. In the thermogalvanic couples tests, the effect of temperature variation on the surface of the container on acceleration of corrosion was evaluated for two alloys; Alloy CDA 102 and Alloy 304L. Long-term immersion tests were conducted in Task 7 of the program.

Beavers, J.A.; Thompson, N.G.; Durr, C.L. [Cortest Columbus Technologies, OH (United States)

1992-01-01

275

Determination of lead in an Sb-Pb alloy by anodic linear scan voltammetry  

Microsoft Academic Search

Anodic linear scan voltammetry (ALSV) has been used to determine the content of Pb (up to 3.5 wt%) in a eutectic type of binary Sb-Pb alloy. The effect of type of electrolyte and as well as the rate of the potential change on the dissolution of Pb from this alloy were investigated by ALSV. The method can be used for

N. Blagojevi?; V. Kastratovi?; R. Zejnilovi?; Ž. Ble?i?

2001-01-01

276

Alloy optimization for PWR steam generator heat-transfer tubing  

NASA Astrophysics Data System (ADS)

Several materials have been used for heat-transfer tubing in light water reactor steam generators, including Type 316 stainless steel (a few early units in the late 1960s), Alloy 600MA (mill annealed), Alloy 600TT (thermally treated), Alloy 800Mod, and the current preference, Alloy 690TT. The susceptibility of Alloy 600MA (Ni-16Cr-9Fe) to stress-corrosion cracking led to extensive corrosion studies to select and qualify a new material. Alloy 690TT (Ni-30Cr-10Fe) was chosen in the mid-1980s as the best heat-transfer tubing material, although Alloy 800Mod (Fe-33Ni-22Cr) remains an alternate choice. The basis for selecting Alloy 690TT is briefly summarized, along with a description of efforts to optimize tube manufacturing practices for corrosion resistance. Efforts at further optimization are described, including preconditioning of the tubing by some form of inner-diameter surface passivation in order to minimize corrosion product release rates upon initial service.

Harrod, D. L.; Gold, R. E.; Jacko, R. J.

2001-07-01

277

Wear behavior of TiNi shape memory alloys  

SciTech Connect

TiNi alloy is a well-known shape memory alloy, which has demonstrated its great potential for a large variety of applications; this alloy is being actively applied to the development of new energy conversion systems, to the design for new robots and smart material systems, and to the development of medical implants and instruments. In addition to its shape memory effect, it has been observed that TiNi alloy also exhibits great resistance to wear. It is expected that the TiNi alloy, with its shape memory effect, vibration-damping feature, and high corrosion resistance, may become a new type of tribo-material and find new engineering applications. The high wear resistance of TiNi alloy may be attributed to its pseudoelastic behavior. This paper presents experimental results on wear behavior of TiNi alloy and its variation with microstructure. The pseudoelasticity of TiNi alloy was also studied, and its possible effect on wear resistance has been discussed in this paper.

Li, D.Y. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering

1996-01-15

278

Reactive brazing of Al alloy to Mg alloy using zinc-based brazing alloy  

Microsoft Academic Search

According to the feature of Mg–Zn eutectic reaction, Al alloy was bonded to Mg alloy by contact reaction brazing using a zinc-based brazing alloy successfully. The experimental observations showed that Mg–Al intermetallic compounds were avoided for the addition of the zinc-based brazing alloy. The Mg substrate and the remanent brazing alloy were bonded with the reaction zone that formed along

Liming Liu; Jinhong Tan; Xujing Liu

2007-01-01

279

Alloys by precision electrodeposition  

NASA Astrophysics Data System (ADS)

We show that a Cu-Ni alloy film of arbitrary composition may be grown by electrodepositing well-defined submonolayer quantities of Cu and Ni in alternation. Active computer control of the deposition process is used to compensate for undesired electrochemical processes, such as partial redissolution of the Ni. Magnetic measurements were used to characterize alloy homogeneity. With this electrodeposition method it is possible to tailor the composition profile of a film with subnanometer precision. As an example, Cu0.19Ni0.81/Cu0.79Ni0.21 alloy/alloy multilayers were fabricated which gave prominent satellite peaks in high angle x-ray diffraction patterns.

Kazeminezhad, I.; Blythe, H. J.; Schwarzacher, W.

2001-02-01

280

Tungsten Alloy Technology.  

National Technical Information Service (NTIS)

The papers collected here represent contributions to the International Conference on Tungsten and its Alloys in which Materials Directorate personnel had primary or secondary authorship responsibility. The conference was held in Arlington, VA, 16-18 Novem...

R. J. Dowding

1993-01-01

281

Application of computed tomography to quality inspection of brass alloy  

NASA Astrophysics Data System (ADS)

A research on application computed tomography to quality inspection of brass alloy has been done. The aim of the research was to study the capability of computed tomography system with source radiation isotope I-131 in order to mapping different quality of any type of brass alloy and study on the influence of activity of isotope I131 to the reconstructed image has been done. The inspection has been done by scanning three type of brass alloy, and comparing to the metal Cu and Zn which are the fundamental substances of brass alloy. The quality of brass alloy was identified through the profile of absorption of radiation and the distribution value of linear coefficient attenuation (?) on the image and image contrast. The influence of activity isotope I-131 was studied by performance through the sinogram and reconstructed image. The result showed that the good quality of brass alloy have highest absorption of radiation than the bad quality of brass alloy, which were represented by the higher value of ?. From the visual observation on the reconstructed image, it showed that the higher activity of isotope I-131 would be used on the scanning process, the sharper sinogram contrast and reconstructed image contrast.

Suparta, Gede Bayu; Handayani, Nita

2009-12-01

282

Superconducting gold alloys  

Microsoft Academic Search

Although the discovery of a gold alloy with a superconducting state at relatively high temperature would be significant and\\u000a exciting, it has been a feature of the past decade that technology has advanced to the stage of producing applications for\\u000a gold and other alloys which achieve superconductivity at low critical temperatures. A significant research effort has gone\\u000a into the search

H. R. Khan

1984-01-01

283

Microstructure and Coercivity in Ball Milled 2-17 Type Sm(Co bal Fe 0.1 Cu 0.1 Zr 0.033 ) 6.93 High Temperature Permanent Magnetic Alloy  

Microsoft Academic Search

The research for novel hard magnetic materials for high temperature advanced power applications is still an active area of\\u000a research. The microstructure and magnetic properties in high temperature hard magnetic alloy have been studied against various\\u000a milling times in high energy ball milling. The average particle size varies from 1 ?m to 50 ?m for ball milling times of 30–180\\u000a minutes while

M. Faisal; Chengbao Jiang

2011-01-01

284

A new thermoelectric alloy for cooling applications  

NASA Astrophysics Data System (ADS)

In the last twenty years no improvements in bulk materials has been achieved for cooling in the thermoelectrics industry that has surpassed the cooling capabilities of the alloys developed at RCA by Yim and Rosi. In that work they achieved a DeltaT of 77.6K from room temperature. This work focuses on the development of a new n-type and improving the p-type alloy from the Bisb2Tesb3-Sbsb2Tesb3-Sbsb2Sesb3 pseudo-ternary alloy system. Improvements in the alloy have allowed the construction of a cooling device that achieves a DeltaT of 79.2K. In bulk material growth the highest figure of merit material, Z, for room temperature cooling applications is a p-type material (Bisb2Tesb3)sb{25}(Sbsb2Tesb3)sb{72}(Sbsb2Sesb3)sb3 that has a Z = 3.6× 10sp{-3}/K and an n-type material (Bisb2Tesb3)sb{90}(Sbsb2Tesb3)sb5(Sbsb2Sesb3)sb5 with a Z = 3.2× 10sp{-3}/K developed at the University of Virginia. The present work improves on these results by developing a new n-type material (Bisb2Tesb3)sb{70}(Sbsb2Tesb3)sb{25}(Sbsb2Sesb2)sb5 with a Z = 3.4× 10sp{-3}/K. The improvement in this new alloy is due to a lower thermal conductivity with equivalent electrical properties to the old n-type alloy (Bisb2Tesb3)sb{90}(Sbsb2Tesb3)sb5(Sbsb2Sesb3)sb5. The temperature dependent properties from 250K-400K of the three alloys with various dopant concentrations was measured to study temperature effects on the thermoelectric properties. Studies were also conducted on ohmic contacts, including measuring the contact resistivity size and the resistivity of the solder. The contact resistivity is an effect that is critical to device performance in small modules. This work also found that the dopant material is relevant to the overall thermoelectric properties of the alloy. In the p-type material (Bisb2Tesb3)sb{25}(Sbsb2Tesb3)sb{72}(Sbsb2Sesb3)sb3 the figure of merit was lowered when SbIsb3 was used instead of Te as a compensator of excess holes. This effect was not apparent in the new n-type alloy (Bisb2Tesb3)sb{70}(Sbsb2Tesb3)sb{25}(Sbsb2Sesb3)sb5. Using the measured temperature dependent properties an improved finite difference model was constructed to evaluate the thermoelectric material. This model improved upon previous models by including the Thomson coefficient and resistance due to the contacts and the metal junctions. This model predicted the maximum cooling of the given thermoelectric material to within 3K of the actual device. Older models based on material parameters either overestimated the cooling by 5K or underestimated it by 3.5K.

Ettenberg, Martin Harris

285

Electrochemical corrosion of titanium and titanium-based alloys  

Microsoft Academic Search

Statement of problem. Two varieties of unalloyed titanium, Ti-6Al-4V and NiTi, commonly are used in medical and dental fields. Several other types of alloys for potential use in these fields have been developed, including Ti-4.5Al-3V-2Mo-2Fe and vanadium-free alloys (Ti-5Al-2.5Fe and Ti-5Al-3Mo-4Zr). The corrosion of these alloys under simulated physiologic conditions is not known. Purpose. This study compared the corrosion behaviors

Chotiros Kuphasuk; Yoshiki Oshida; Carl J. Andres; Suteera T. Hovijitra; Martin T. Barco; David T. Brown

2001-01-01

286

Radiation-induced segregation in candidate fusion-reactor alloys  

SciTech Connect

The effect of radiation on surface segregation of minor and impurity elements has been studied in four candidate fusion reactor alloys. Radiation induced surface segregation of phosphorus was found in both 316 type stainless steel and in Nimonic PE-16. Segregation and depletion of the other alloying elements in 316 stainless steel agreed with that reported by other investigators. Segregation of nitrogen in ferritic HT-9 was enhanced by radiation but no phosphorus segregation was detected. No significant radiation enhanced or induced segregation was observed in a Ti-6Al-4V alloy. The results indicate that radiaton enhanced grain boundary segregation could contribute to the embrittlement of 316 SS and PE-16.

Brimhall, J.L.; Baer, D.R.; Jones, R.H.

1981-07-01

287

Cobalt base alloy  

SciTech Connect

A cobalt base alloy having a superior high-temperature strength and high-temperature ductility, containing, by weight, 0.15 to 2% carbon, less than 2% silicon, less than 2% manganese, 5 to 15% nickel, 18 to 35% chromium, 3 to 15% tungsten, 0.003 to 0.1% boron, 0.01 to 1% niobium, 0.01 to 1% zirconium, less than 10% iron, less than 1% tantalum, less than 1% hafnium and remainder cobalt. At least one of 0.01 to 1 wt% titanium and 0.01 to 1 wt% (combined amount) rare earth elements is added to the alloy. The alloy is used as a casting and contains eutectic carbides and secondary carbides precipitated substantially uniformly in the grains. If the secondary carbides are formed by an age-treatment conducted at a higher temperature than that at which the alloy is actually used, the high-temperature strength and the high-temperature ductility of the alloy are remarkably improved. The cobalt base alloy is formed into gas turbine nozzles by a precision casting.

Fukui, Y.; Kashimura, T.

1984-03-20

288

Dependence of melting, roughness and contact resistances on Ge and Ni content in alloyed AuGe/Ni/Au-type electrical contacts to GaAs/AlGaAs multilayer structures  

NASA Astrophysics Data System (ADS)

Annealed AuGe/Ni/Au film structures on GaAs/AlGaAs multilayers have been examined for contact resistance, roughness, magnetization and melting as functions of anneal temperature, Ni-layer thickness and three AuGe compositions. Magnetization data indicate that a solid state, solubility-limited dissolution of Ni into AuGe takes place even for low-temperature anneals and that this dissolution is complete when alloying occurs at ~400 °C. An apparent melting temperature, detected in differential scanning calorimetry, increases with increasing Ni-layer thickness and decreasing Ge content in the AuGe alloy. Electrical contact formation and roughening of the surface occur in the range of melting temperatures of the structure. The eutectic alloy with a Ni-layer thickness of ~25-30 nm gives the optimum contact resistance. The contact resistance can be traded off for the reduction in roughness by either increasing the Ni-layer thickness or reducing the Ge content, with the latter being the better choice of the two. The temperature dependence (4-300 K) of the contact resistance shows indications of both thermionic and tunneling behaviors. The barrier height for the current conduction increases with the increase of the Ni-layer thickness and a decrease of the Ge content in the AuGe layer, relative to that of the structure with optimum contact resistance.

Abhilash, T. S.; Kumar, Ch Ravi; Sreedhar, B.; Rajaram, G.

2010-03-01

289

Stress self-accommodation characteristic of Fe-Mn-Si shape memory alloy  

NASA Astrophysics Data System (ADS)

The paper presents the stress self-accommodation characteristic of Fe-Mn-Si shape memory alloy, namely the alloy causes positive/reverse ? martensitic transformation and accompanied by deformation in order to adapt the variation of the outside macroscopical stress and deformation. From XRD analysis, it is found that the stress-induced ?<-->? martensitic transformation and its reverse transformation would occur in Fe-Mn-Si shape memory alloy under the tension-compression stress and also validated the stress self-accommodation characteristic of Fe-Mn-Si shape memory alloy. In cycles of tension and compression deformation, the stress self-accommodation characteristic of Fe-Mn-Si shape memory alloy can increase fatigue life of the alloy by reducing stress concentration, restraining plastics gliding deformation and delaying the formation and growing of microcracks. The fatigue fracture in Fe-Mn-Si alloy shows quasi-cleavage brittle rupture type.

Lin, Chengxin; Liu, Linlin; Sun, Deping; Wang, Yizhuo; Zhou, Chaoyu

2009-07-01

290

Metallographic evaluation of the reactions between boronated graphite and Fe-Ni-Cr alloys  

SciTech Connect

The compatibility of boronated graphite with alloy 800H and type 316 stainless steel was evaluated metallographically after exposures at 700 and 810/sup 0/C for up to 10,000 h. At 700/sup 0/C, the principal reaction with both alloys was limited oxidation. At 810/sup 0/C, three types of reactions were observed: localized reactions at sites where the B/sub 4/C particles were in contact with the alloys' surfaces, intergranular penetration (much more prevalent for alloy 800H), and carburization.

Tortorelli, P.F.; Mayotte, J.R.; Henson, T.J.; DeVan, J.H.

1984-01-01

291

Metallography of dilute Mg-Nd-Zn alloys  

Microsoft Academic Search

Electron microscopy and electrical resistivity techniques have been used to examine the metallography and kinetics of precipitation in a magnesium alloy containing 2.8% Nd and 1.3% Zn. The alloy is shown to be of the age-hardening type with a precipitation sequence: Supersaturated solution-low-temperature reaction-..gamma..''-..gamma... The nature of the low-temperature reaction has not been fully elucidated but is thought not to

P. A. Nuttall; T. J. Pike; B. Noble

1980-01-01

292

Analysis of phases in a Cu–Cr–Zr alloy  

Microsoft Academic Search

Phases of a Cu–0.31%Cr–0.21%Zr alloy were analyzed by scanning electronic microscope and energy dispersive X-ray spectroscopy (EDXS) and transmission electronic microscope (TEM). The EDXS results showed that there are three types of phases in the alloy, Cu-matrix, chromium-rich and zirconium-rich phases; coarse phases mainly consist of zirconium-rich phase. TEM result showed that fine chromium distributed in matrix and Cu51Zr14 phase

Huang Fuxiang; Ma Jusheng; Ning Honglong; Geng Zhiting; Lu Chao; Guo Shumei; Yu Xuetao; Wang Tao; Li Hong; Lou Huafen

2003-01-01

293

Preparation and properties of mechanically alloyed rare earth permanent magnets  

Microsoft Academic Search

Mechanical alloying is applied to prepare Nd-Fe-B and ThMn12-type permanent magnets. Starting from element powders, the hard-magnetic phases are formed by milling in a planetary ball mill and a successive solid-state reaction at relatively low temperatures. For Nd-Fe-B, the magnetically isotropic particles are microcrystalline, show a high coercivity (up to 20 kOe for ternary alloys and above for Dy-substituted samples)

L. Schultz; K. Schnitzke; J. Wecker

1989-01-01

294

Structural Investigation of Noncrystalline Nickel-Phosphorus Alloys  

Microsoft Academic Search

The structure of noncrystalline electrodeposited Ni&sngbnd;P alloys, 73.8–81.4 at.% Ni, has been investigated by x-ray scattering and by physical density measurements. The x-ray interference functions, I(k), are qualitatively inconsistent with those calculated for fcc-, hcp-, and Ni3P-type crystallites. Calculated radial distribution functions RDF(r) indicate that the alloys have a better defined short-range order than that observed in liquid noble metals

G. S. Cargill

1970-01-01

295

Crevice Corrosion of Austenitic Alloys in High-Temperature Water  

Microsoft Academic Search

Oxide film characterizations and electrochemical measurements were carried out on crevices of austenitic stainless alloys to investigate the acceleration mechanism of intergranular stress corrosion cracking (IGSCC) in high-temperature water. When the chromium concentration was sufficient, type 304 (UNS S30400) stainless steel (SS) and alloy 600 (UNS N06600) exhibited good corrosion performance in crevices, forming a chromium-enriched layer in an oxide

N. Saito; H. Sakamoto; K. Sugimoto

1998-01-01

296

Magnetically hard alnico 5 alloy with a mischmetal addition  

Microsoft Academic Search

The addition of mischmetal (CeMM) to the Alnico 5 alloy of equiaxial grain structure in the amounts from 0.0 to 0.31 wt% and its effect on the magnetic properties, the crystal structure and on the type of non-metallic inclusions in the alloy has been studied. The addition of CeMM, in amounts within the examined limits, was found to cause a

S. Szymura

1983-01-01

297

Mechanisms for the hot corrosion of nickel-base alloys  

Microsoft Academic Search

The Na2SO4-induced accelerated oxidation of nickel-base alloys containing elements such as Cr, Al, Mo, W, and V has been studied in\\u000a 1.0 atm O2 in the temperature range of 650? to 1000?C. It has been found that the hot corrosion behavior of these alloys can usually\\u000a be characterized according to one of two types of attack: 1) Na2SO4-induced accelerated oxidation;

J. A. Goebel; F. S. Pettit; G. W. Goward

1973-01-01

298

High Cycle Fatigue of Nickel Base Alloys.  

National Technical Information Service (NTIS)

High cycle fatigue data for the alloys Nimonic alloy 901, Inconel alloy 718, Nimonic alloy 90, Nimonic alloy 115 and Nimocast alloy 738LC were determined at elevated temperatures. The effect of long term thermal exposure on the high cycle fatigue properti...

G. M. McColvin

1977-01-01

299

Ultraprecision microelectroforming of metals and metal alloys  

NASA Astrophysics Data System (ADS)

In recent years, microsystem technology and its growing importance for actuators, sensors, optics and microfluidics, only to name a few, have gained a lot of attention. Specific applications demand fabrication techniques allowing a fast and reliable replication of microstructure products in a variety of materials. An important technique for replication processes of microstructures in many applications of microsystem technology are microelectroforming processes, generating a variety of metals and metal alloys with tailored characteristics. Here, new results in the development of alloys for specific applications as well as their applications are reported: (1) Newly developed alloys: Nickel-iron alloys enable the production of soft magnetic microstructures e.g. for specific applications in microactuators. Nickel-cobalt and Nickel-tungsten alloys have been employed for the manufacture of microstructured tools with excellent mechanical properties regarding wear and mechanical durability. These tools have been applied to hot-embossing and injection molding processes successfully. (2) Microelectroforming within the frame of the LIGA technique allows the manufacturing of extremely precise electrodes with various cross-sections and heights for (mu) - electro discharge machining. The combination of these techniques enables the production of microstructures from non- electrodepositable materials, like stainless steel e.g. for large scale replication processes. (3) The precision of microelectroforming enables the replication of structured surfaces on a nanoscale for molecular microelectronics or special applications. The new types of alloys reported here significantly enlarge the applicability of microelectroforming processes for tool fabrication or direct use. Moreover combining this process with other microstructuring processes like injection molding or (mu) -EDM techniques generates a powerful tool for microsystem technology.

Loewe, Holger; Ehrfeld, Wolfgang; Diebel, Joerg

1997-09-01

300

Long-period states of ordered metal alloys. 1. Analysis of structural features  

NASA Astrophysics Data System (ADS)

An analysis of empirical data establishes the presence at least two different types of long-period structures. The first type of structure is seen in alloys of the system Cu-Au, Cu3Pd, Cu3Pt, etc., while the second type is found in alloys Ag3Mg and Al3Ti and their analogs. It was concluded that the nature of the long-period states is different in the two types of structures.

Potekaev, A. I.

1995-06-01

301

Review of Recent Developments. Nickel- and Cobalt-Base Alloys.  

National Technical Information Service (NTIS)

Contents: Alloy development and evaluation; (Cast nickel-base alloys; Turbine-blade alloy for thin sections, Evaluation of alloys for use in hot working); (Dispersion-strengthened alloys, Dispersion-strengthened cobalt alloys for turbine vanes); Oxidation...

V. F. Beuhring W. F. Simmons

1970-01-01

302

Metallurgical aspects and corrosion behavior of yellow low-gold alloys.  

PubMed

Three copper-free type III yellow low-gold alloys (Ag-Au-In-Pd-Zn) were investigated. Microstructural analysis was performed with x-ray diffraction, light microscopy, and an electron x-ray micro-analysis. The electrochemical behavior of the alloys was tested with standard potentiodynamic techniques in 0.9% saline solution and an artificial saliva and compared with that of a traditional high-gold alloy. The three alloys turned out to be two-phase mixtures of a fcc (matrix) and a bcc (island) phase. The yellow color, present in spite of the low-gold content, was caused by the disordered Pd-In, island-type structure. An additional third structure was seen after etching. However, no distinct phase could be correlated with it. The corrosion behavior for the experimental alloys, based on cyclic polarization, can be considered acceptable in both electrolytes used, but is inferior to that of the control alloy. PMID:2638280

Mezger, P R; Stols, A L; Vrijhoel, M M; Greener, E H

1989-09-01

303

Alloying and heat treatment of heat-resistant alloys  

Microsoft Academic Search

A group of domestic alloys based on nickel compares favorably with similar foreign alloys in their lack or limited concentration of nickel but having the same long-term strength. The properties of domestic and foreign alloys have been compared in numerous reviews, and therefore this paper will be confined to the scientific achievements and formulation of modern principles of creating heat

S. B. Maslenkov

1977-01-01

304

Formation of single-walled bimetallic coinage alloy nanotubes in confined carbon nanotubes: molecular dynamics simulations.  

PubMed

The growth of single-walled bimetallic Au-Ag, Au-Cu and Ag-Cu alloy nanotubes (NTs) and nanowires (NWs) in confined carbon nanotubes (CNTs) has been investigated by using the classical molecular dynamics (MD) method. It is found that three kinds of single-walled gold-silver, gold-copper and silver-copper alloy NTs could indeed be formed in confined CNTs at any alloy concentration, whose geometric structures are less sensitive to the alloy concentration. And an extra nearly pure Au (Cu) chain will exist at the center of Au-Ag (Au-Cu and Ag-Cu) NTs when the diameters of the outside CNTs are big enough, thus producing a new type of tube-like alloy NWs. The bonding energy differences between the mono- and hetero-elements of the coinage metal atoms and the quasi-one-dimensional confinement from the CNT play important roles in suppressing effectively the "self-purification" effects, leading to formation of these coinage alloy NTs. In addition, the fluid-solid phase transition temperatures of the bimetallic alloy NTs are found to locate between those of the corresponding pure metal tubes. Finally, the dependences of the radial breathing mode (RBM) frequencies and the tube diameters of the alloy NTs on the alloying concentration were obtained, which will be very helpful for identifying both the alloying concentration and the alloy tube diameters in future experiments. PMID:24013729

Han, Yang; Zhou, Jian; Dong, Jinming; Yoshiyuki, Kawazoe

2013-09-25

305

Mechanical alloying and high pressure processing of a TiAl-V intermetallic alloy.  

PubMed

An alloy with a chemical composition of Ti-45Al-5V (at.%) was synthesized by mechanical alloying in a Szegvari-type attritor from elemental powders of high purity. Before compaction, the powders were characterized by X-ray diffraction and scanning as well as transmission electron microscopy. The compaction of powders was carried out by hot isostatic pressing and hot isostatic extrusion. The resulting material was subjected to microstructural and mechanical characterization. The microstructure investigated by transmission and scanning electron microscopy supplemented by X-ray diffraction revealed that the bulk material was composed of a mixture of TiAl- and Ti(3)Al-based phases, however, the typical lamellar microstructure for such alloys was not observed. The materials exhibited exceptionally high yield strength together with satisfactory ductility and fracture toughness. The high strength was unequivocally due to grain refinement and the presence of oxide dispersoid. PMID:20500422

Dymek, S; Wróbel, M; Witczak, Z; Blicharski, M

2010-03-01

306

Utilization of titanium alloy equipment  

Microsoft Academic Search

Alloys AT-3 and AT-6 have wide application in practice in contrast to many series containing titanium alloyed with cheap obtainable elements such as aluminum, chromium, iron, silicon, and boron. Alloys AT-3 and AT-6 are processable. Extruded electrodes consisting of magnesio-thermic titanium and added alloying elements were fused twice in a vacuum arc furnace in an argon atmosphere. After machining to

N. M. Shmakov; V. S. Mikheev

1974-01-01

307

Charge-density-shear-moduli relationships in aluminum-lithium alloys.  

PubMed

Using the first principles full-potential linear-augmented-Slater-type orbital technique, the energies and charge densities of aluminum and aluminum-lithium supercells have been computed. The experimentally observed increase in aluminum's shear moduli upon alloying with lithium is argued to be the result of predictable changes to aluminum's total charge density, suggesting that simple rules may allow the alloy designer to predict the effects of dilute substitutional elements on alloy elastic response. PMID:11690484

Eberhart, M

2001-10-26

308

Charge-Density-Shear-Moduli Relationships in Aluminum-Lithium Alloys  

NASA Astrophysics Data System (ADS)

Using the first principles full-potential linear-augmented-Slater-type orbital technique, the energies and charge densities of aluminum and aluminum-lithium supercells have been computed. The experimentally observed increase in aluminum's shear moduli upon alloying with lithium is argued to be the result of predictable changes to aluminum's total charge density, suggesting that simple rules may allow the alloy designer to predict the effects of dilute substitutional elements on alloy elastic response.

Eberhart, Mark

2001-11-01

309

Corrosion Properties of Lightweight and High-strength 2195 Al-Li Alloy  

Microsoft Academic Search

The intergranular corrosion and exfoliation corrosion of 2195 Al-Li alloy treated by multi-step heating-rate controlled aging (MSRC) are studied. The corrosion features of 2195 Al-Li alloys which are respectively treated by high-temperature nucleation MSRC (H-M) and low-temperature nucleation MSRC (L-M) are contrasted. And the corrosion mechanism of 2195 Al-Li alloy is also discussed from the viewpoint of microstructure (types, distribution,

Yue XU; Xiaojing WANG; Zhaotong YAN; Jiaxue LI

2011-01-01

310

Plasticity of D16T aluminum alloy during biaxial extension at low temperatures  

Microsoft Academic Search

Conclusions 1.Annealed D16T aluminum alloy exhibits anisotropy of its elastic and plastic properties. Alloy plasticity is 45% higher and the Young's modulus 9.5% lower in the rolling direction than in that perpendicular to it.2.The anisotropy of both elastic and plastic properties decreases as the test temperature is reduced.3.The deformability of the alloy depends on the type of stress pattern and

G. S. Pisarenko; B. I. Koval'chuk; A. A. Lebedev

1971-01-01

311

Room temperature mechanical properties and tribology of NICRALC and Stellite casting alloys  

Microsoft Academic Search

NICRALC is a family of intermetallic compound-based casting alloys proposed as an economic alternative for abrasion and erosion-resistant cobalt alloys, mainly under more elevated temperature conditions. NICRALC microstructures contain hard chromium carbides dispersed in a continuous Ni–Al–Cr ?? (L12) ordered intermetallic matrix. In this work, cast NICRALC alloys with different carbon contents, different carbide types and morphological features were compared

W. S. da Silva; R. M. Souza; J. D. B. Mello; H. Goldenstein

2011-01-01

312

Wear, corrosion and cracking resistance of some W- or Mo-containing Stellite hardfacing alloys  

Microsoft Academic Search

Traditional Stellite hardfacing materials are Co–Cr–W–C type of alloys. A series of new Stellite alloys are developed based on Co–Cr–Mo–C system. Immersion–corrosion test is conducted in 10% HNO3 oxidizing acid at boiling temperature, in 10% H2SO4 reducing acid at 66°C and in 5% HCl reducing acid at 40°C to evaluate the general corrosion resistance of the Stellite alloys. The abrasive,

M. X. Yao; J. B. C. Wu; Y. Xie

2005-01-01

313

STM\\/AFM studies of the evolution of morphology of electroplated Ni\\/W alloys  

Microsoft Academic Search

The surface morphology evolution of Ni\\/W alloys was studied, as a function of the alloy composition. Using the modified plating baths developed in our laboratory recently, electroplated Ni\\/W alloys with different W content, in the range of 7–67atom percent (a\\/o), can be obtained. This was found to lead to different structures, ranging from polycrystalline fcc-Ni type structure to amorphous, followed

L. Zhu; O Younes; N Ashkenasy; Y Shacham-Diamand; E Gileadi

2002-01-01

314

Structure and magnetic properties of mechanically alloyed SmCo7 compound  

Microsoft Academic Search

The relationship between phase transformation and magnetic properties of mechanically alloyed (MA) SmCo7 alloys at different annealing temperatures has been studied. The MA alloy is a mixture of an amorphous phase and a TbCu7-type phase, and has low coercivity. Upon annealing, the coercivity initially increases with the amount of SmCo7 phase. Maximum coercivity of 18 kOe has been obtained on

Jun Yang; O. Mao; Z. Altounian

1996-01-01

315

Effect of grain refinement on the fluidity of two commercial Al-Si foundry alloys  

Microsoft Academic Search

The effect of grain refinement on the fluidity of AlSi7Mg and AlSi11Mg has been investigated by spiral tests. Two different\\u000a types of grain refiners have been evaluated. An AlTi5Bl master alloy was added to different Ti contents. Since the commercial\\u000a alloys had a high initial content of titanium, model alloys were made to investigate the fluidity at low grain refiner

A. K. Dahle; P. A. Tøndel; C. J. Paradies; L. Arnberg

1996-01-01

316

Microstructural evolution of rolled Mg5Zn3Nd(Zr) alloy  

Microsoft Academic Search

A mini-type rolling machine was employed for multi-passes rolling of a Mg-5Zn-3Nd(-Zr)(mass fraction, %) wrought alloy. For the sake of providing experimental basis for magnesium alloy rolling process, optical microscopy, SEM and TEM observations were used to study the microstructure evolution of magnesium alloys subjected to different rolling reductions before and after annealing. Investigations show that multi-passes can be achieved

Lin YANG; Xiao-dan GAO; Li LIN; Peng ZOU; Li-jia CHEN; Zheng LIU

2010-01-01

317

Segregation phenomena at growing alumina/alloy interfaces  

SciTech Connect

The chemistry and structure at the scale/alloy interface are important factors governing scale adhesion. The chemical changes can occur from segregation of impurities in the alloy, such as sulphur and carbon, or alloying elements such as chromium, aluminium and reactive elements. This paper reviews studies of the changes of interfacial composition with oxidation time for Al{sub 2}O{sub 3} formed on several model alumina-forming alloys, and tries to relate that to the interfacial strength. Results show that sulphur segregation to oxide/metal interfaces can indeed occur, but the type and amount of segregants at the interface depend on the alloy composition and the interface structure. Co-segregation of impurities with alloying elements can also occur, resulting in multi-layer segregants at the interface. Sulphur-containing interfaces are indeed weaker, but the major role of sulphur is to enhance interfacial void formation. Reactive elements in the alloy not only gather sulfur but also exert an additional positive effect on scale adhesion.

Hou, Peggy Y.

2005-03-30

318

Solidification of an alloy 625 weld overlay  

Microsoft Academic Search

The solidification behavior (microsegregation, secondary phase formation, and solidification temperature range) of an Alloy\\u000a 625 weld overlay deposited on 2.25Cr - 1Mo steel by gas metal arc welding was investigated by light and electron optical microscopy,\\u000a electron microprobe, and differential thermal analysis techniques. The overlay deposit was found to terminate solidification\\u000a at ? 1216 C by a?\\/Laves eutectic-type reaction. The

J. N. DuPont

1996-01-01

319

Glow discharge amorphous silicon tin alloys  

Microsoft Academic Search

We present basic density of states, photoresponse, and transport measurements made on low bandgap s-SiSn:H alloys produced by RF glow discharge deposition of SiH4, H2 and Sn(CH3)4. Major changes in the local bonding structure and the density of states are demonstrated, yet the normalized photoresponse remains poor. It is shown that two types of defect levels are produced with Sn

A. H. Mahan; B. von Roedern; A. Madan; A. Sanchez; D. L. Williamson

1984-01-01

320

Cobalt-base ferromagnetic shape memory alloys  

Microsoft Academic Search

Single crystalline and polycrystalline CoxNiyGa100-(x+y), 41 < xCo< 62 and 19.3 < yNi < 32.7, Ferromagnetic Shape Memory Alloys have been produced in the range of the Heusler-type composition. Elasto-mechanical properties have been analyzed for the annealed and quenched states, respectively. The mechanical spectroscopy data show the occurrence of martensitic phase transformation with the transition range and characteristics depending on

Corneliu M. Craciunescu; Yoichi Kishi; Marc De Graef; Thomas A. Lograsso; Manfred R. Wuttig

2002-01-01

321

Erosion plume dynamics during pulsed laser alloying  

Microsoft Academic Search

Dynamics of erosion plume during pulsed laser alloying (? = 1.06 ?m, pulse duration in millisecond range, power density 105–106 W\\/cm2) of Fe with Mo, Al, Sn was analysed by means of high speed photorecording. Two qualitatively different types of plume dynamics were found: cylindrical vapour helixes and periodic pulsation. The monitoring of plume dynamics and melt ejection allows one

V. Titov; I. Smurov; M. Ignatiev

1996-01-01

322

Magnetic Properties of Rare-Earth Metals and Alloys  

Microsoft Academic Search

A review of neutron diffraction studies of the magnetic properties of rare-earth metals and alloys is presented. For each of the pure metals Tb, Dy, Ho, Er, and Tm there is observed a transition at a temperature TN to an oscillatory antiferromagnetic configuration (helical or linear oscillator type). At lower temperatures, further transitions to ferromagnetic, ferromagnetic spiral, or antiphase domain-type

W. C. Koehler

1965-01-01

323

Solidification of an alloy 625 weld overlay  

NASA Astrophysics Data System (ADS)

The solidification behavior (microsegregation, secondary phase formation, and solidification temperature range) of an Alloy 625 weld overlay deposited on 2.25Cr - 1Mo steel by gas metal arc welding was investigated by light and electron optical microscopy, electron microprobe, and differential thermal analysis techniques. The overlay deposit was found to terminate solidification at ? 1216 °C by a ?/Laves eutectic-type reaction. The Laves phase was highly enriched in Nb, Mo, and Si. The solidification reaction and microsegregation potential of major alloying elements in the overlay deposit are compared to other Nb-bearing Ni base alloys and found to be very similar to those for Alloy 718. Solidification cracks observed in the overlay were attributed to the wide solidification temperature range (?170 °C) and formation of interdendritic ( ?+Laves) constituent. Reasonable agreement is obtained between the calculated and measured volume percent ( ?+Laves) constituent with the Scheil equation by treating the overlay system as a simple ?-Nb “binary” and using an experimentally determined k Nb value from electron microprobe data.

Dupont, J. N.

1996-11-01

324

Cobalt-base ferromagnetic shape memory alloys  

NASA Astrophysics Data System (ADS)

Single crystalline and polycrystalline CoxNiyGa100-(x+y), 41 < xCo< 62 and 19.3 < yNi < 32.7, Ferromagnetic Shape Memory Alloys have been produced in the range of the Heusler-type composition. Elasto-mechanical properties have been analyzed for the annealed and quenched states, respectively. The mechanical spectroscopy data show the occurrence of martensitic phase transformation with the transition range and characteristics depending on the state and the composition of the alloys. For XCo approximately equals 49 +/- 1 at percent, the Ni/Ga ratio was shown to be in direct relationship with the transition temperature range, from an Ms of -100 degrees C for Ni/Ga approximately equals (21/29) to a +150 degrees C for a Ni/Ga ratio of about (26/25). For Ga approximately equals 27 +/- 0.4 at percent, the Co/Ni ratio is in indirect relationship with the transition temperature, with an Ms of -125 degrees C for a (53/19) ratio to a +175 degrees C for a ratio of about (49/26). Optical and electron microscopy shows that a typical thermoelastic martensitic transformation occurs. The L21 Structurbericht parent phase transforms into monoclinic or orthohombic martensitic upon cooling. The formation of a Co-rich phase has been observed for alloys with lower Ga content and is considered to be one of the reasons for the difference in the transformation range for annealed and quenched alloys.

Craciunescu, Corneliu M.; Kishi, Yoichi; De Graef, Marc; Lograsso, Thomas A.; Wuttig, Manfred R.

2002-07-01

325

Reduction in Defect Content in ODS Alloys  

SciTech Connect

The work detailed within this report is a continuation of earlier work that was carried out under contract number IDX-SY382V. The earlier work comprised a literature review of the sources and types of defects found principally in Fe-based ODS alloys together with a series of experiments designed to identify defects in ODS Fe{sub 3}Al material and recommend methods of defect reduction. Defects found in the Mechanically Alloyed (MA) ODS Fe{sub 3}Al included regions of incomplete MA, porosity, intrusions and fine-grained stringers. Some defects tended to be found in association with one another e.g. intrusions and fine-grained stringers. Preliminary powder separation experiments were also performed. The scope and objectives of the present work were laid out in the technical proposal ``Reduction in Defect Content in ODS Alloys--II'' which formed the basis of amendment 3 of the current contract. The current studies were devised in the context of the preceding work with a view to extending and concluding certain experiments while exploring new avenues of investigation of defect control and reduction where appropriate. All work proposed was within the context of achieving an ODS Fe{sub 3}Al alloy of improved overall quality and potential creep performance (particularly) in the consolidated, release condition. The interim outturn of the experimental work performed is also reported.

Ritherdon, J.; Jones, A.R.

2000-02-01

326

A sourcebook of titanium alloy superconductivity  

NASA Astrophysics Data System (ADS)

The development, properties, and applications of Ti-based superconducting alloys are presented in a handbook based on an extensive review of published investigations. The literature is compiled and characterized in a table arranged by alloy, and individual chapters are devoted to unalloyed Ti; Ti-V binary alloys; binary Ti-Cr, Ti-Mn, Ti-Fe, Ti-Co, and Ti-Ni alloys; binary alloys of Ti with the 4d and 5d transition elements; ternary alloys of Ti with simple and transition metals; Ti-Nb binary alloys; Ti-Nb alloys with small amounts of B, C, N, or O; ternary alloys of Ti-Nb with simple metals; Soviet technical alloys; Ti-Zr-Nb alloys; other Ti-Nb-transition-metal alloys; Ti-Nb-based quaternary alloys; and amorphous Ti-alloy superconductors. Tables, graphs, diagrams, and micrographs are provided.

Collings, E. W.

1983-09-01

327

Metallographic study and wear resistance of a high-C wrought Co-based alloy Stellite 706K  

Microsoft Academic Search

The new CoCrMoC type wrought alloy Stellite 706K is an improved alloy over the CoCrWC type wrought alloy Stellite 6K in wear and corrosion resistance. The microstructure of Stellite 706K is characterized by CoCrMo solid solution matrix with banding and occasional twinning and various carbide phases. Pin-on-disc wear resistance of Stellite 706K at room temperature is evaluated. Solution treatment at

M. X. Yao; J. B. C. Wu; W. Xu; R. Liu

2005-01-01

328

Study of corrosion between a titanium implant and dental alloys.  

PubMed

The infiltration of saliva into the multi-metallic structures on titanium implants brings different types of alloys into temporary or permanent contact. In this way a galvanic cell is established as a result of their potential difference. The galvanic cell phenomenon is compounded by another type of corrosion resulting from the geometry of the assembly: localized crevice corrosion. Fifteen galvanic couples (Ti/gold-based alloys, Ti/palladium-based alloy and Ti/non-precious alloys) were studied. Various electrochemical parameters (Ecorr, Ecommon, Ecouple corr, Ecrevice, icorr, icouple corr and Tafel slopes) were analysed. The galvanic currents measured are of the same order of magnitude (except Ti/stainless steel). They remain low. Application of the mixed-potential theory shows that titanium in coupling with the alloys studied will be under either cathodic or anodic control. According to the results obtained, an alloy that is potentially usable for superstructures in a galvanic coupling with titanium must fulfil a certain number of parameters: in a coupling, titanium must have a weak anodic polarization; the current generated by the galvanic cell must also be weak; the crevice potential must be markedly higher than the common potential. PMID:8027459

Reclaru, L; Meyer, J M

1994-06-01

329

Iron aluminide alloys with improved properties for high temperature applications  

DOEpatents

An improved iron aluminide alloy of the DO.sub.3 type that has increased room temperature ductility and improved high elevated temperature strength. The alloy system further is resistant to corrosive attack in the environments of advanced energy corrosion systems such as those using fossil fuels. The resultant alloy is relatively inexpensive as contrasted to nickel based and high nickel steels currently utilized for structural components. The alloy system consists essentially of 26-30 at. % aluminum, 0.5-10 at. % chromium, 0.02-0.3 at. % boron plus carbon, up to 2 at. % molybdenum, up to 1 at. % niobium, up to 0.5 at. % zirconium, up to 0.1 at. % yttrium, up to 0.5 at. % vanadium and the balance iron.

McKamey, Claudette G. (Knoxville, TN); Liu, Chain T. (Oak Ridge, TN)

1990-01-01

330

Effects of Rh on the thermoelectric performance of the p-type Zr{sub 0.5}Hf{sub 0.5}Co{sub 1-x}Rh{sub x}Sb{sub 0.99}Sn{sub 0.01} half-Heusler alloys  

SciTech Connect

We show that Rh substitution at the Co site in Zr{sub 0.5}Hf{sub 0.5}Co{sub 1-x}Rh{sub x}Sb{sub 0.99}Sn{sub 0.01} (0<=x<=1) half-Heusler alloys strongly reduces the thermal conductivity with a simultaneous, significant improvement of the power factor of the materials. Thermoelectric properties of hot-pressed pellets of several compositions with various Rh concentrations were investigated in the temperature range from 300 to 775 K. The Rh 'free' composition shows n-type conduction, while Rh substitution at the Co site drives the system to p-type semiconducting behavior. The lattice thermal conductivity of Zr{sub 0.5}Hf{sub 0.5}Co{sub 1-x}Rh{sub x}Sb{sub 0.99}Sn{sub 0.01} alloys rapidly decreased with increasing Rh concentration and lattice thermal conductivity as low as 3.7 W/m*K was obtained at 300 K for Zr{sub 0.5}Hf{sub 0.5}RhSb{sub 0.99}Sn{sub 0.01}. The drastic reduction of the lattice thermal conductivity is attributed to mass fluctuation induced by the Rh substitution at the Co site, as well as enhanced phonon scattering at grain boundaries due to the small grain size of the synthesized materials. - Graphical abstract: Significant reduction of the lattice thermal conductivity with increasing Rh concentration in the p-type Zr{sub 0.5}Hf{sub 0.5}Co{sub 1-x}Rh{sub x}Sb{sub 0.99}Sn{sub 0.01} half-Heusler materials prepared by solid state reaction at 1173 K.

Maji, Pramathesh [Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Department of Chemistry, University of New Orleans, New Orleans, LA 70148 (United States); Takas, Nathan J.; Misra, Dinesh K. [Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Gabrisch, Heike [Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Department of Chemistry, University of New Orleans, New Orleans, LA 70148 (United States); Stokes, Kevin [Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Department of Physics, University of New Orleans, New Orleans, LA 70148 (United States); Poudeu, Pierre F.P., E-mail: ppoudeup@uno.ed [Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Department of Chemistry, University of New Orleans, New Orleans, LA 70148 (United States)

2010-05-15

331

Thermoelectric Properties of Doped BiSb Alloy Thin Films  

NASA Astrophysics Data System (ADS)

It is well known that undoped BiSb alloys are good n-type thermoelements. We have observed that the power factor (S^2 ?) for MBE-grown BiSb thin films grown on CdTe(111) peak at a significantly higher temperature (250K) than previous results for the bulk alloy (80K), possibly due to an enhanced bandgap. In order to achieve p-type BiSb alloy thin films for a thermoelectric device, and to understand the doping behavior of extremely narrow bandgap materials (40 meV), we performed doping experiments on semiconducting Bi_0.91Sb_0.09 alloy thin films. The electronic and transport properties of Bi and BiSb alloys are very sensitive to the presence of impurities. We used the group IV(VI) element Sn(Te) as an acceptor(donor). Thermopower (TEP), electrical resisitivity, and Hall effect were studied in the range of temperatures 2-300 K. Doping Sn into the BiSb system causes the TEP to change sign (from negative to positive). The maximum value of the TEP can be controlled with the Sn dopant concentration. Both p-type and n-type doping can be easily achieved in BiSb films. Highly Te or Sn-doped samples show degenerate behavior. (This work is supported by DARPA, ARPA and ONR.)

Cho, S.; Divenere, A.; Wong, G. K.; Ketterson, J. B.; Meyer, J. R.; Hoffman, C. A.

1998-03-01

332

High-coercivity decomposition in Fe-(15, 23)%Co-30%Cr-3%Mo-0.5% Ti alloys  

NASA Astrophysics Data System (ADS)

The dependences of the magnetic properties of Fe-(15, 23)%Co-30%Cr-3%Mo-0.5% Ti alloys on the temperatures of isothermal thermomagnetic treatment and the second stage of two-stage magnetic annealing and the results of thermomagnetic analysis of these alloys demonstrate that the sequence of high-coercivity decomposition in them differs from that in alloys with lower contents of chromium, molybdenum, and titanium. The decomposition in the Fe-(15, 23)%Co-30%Cr-3%Mo-0.5% Ti alloys is similar to that in Alnico-type (YuNDKT) alloys with high cobalt (38-42%) and titanium (8%) contents.

Shubakov, V. S.

2009-04-01

333

Aluminum alloys for satellite boxes : engineering guidelines for obtaining adequate strength while minimizing residual stresses and machining distortion.  

SciTech Connect

This report provides strategies for minimizing machining distortion in future designs of aluminum alloy satellite boxes, based in part on key findings from this investigation. The report outlines types of aluminum alloys and how they are heat treated, how residual stresses develop during heat treatment of age hardening alloys, ways residual stresses can be minimized, and the design of machining approaches to minimize distortion in parts that contain residual stresses. Specific recommendations are made regarding alloy selection, heat treatment, stress relieving, and machining procedures for boxes requiring various strength levels with emphasis on 6061 and 7075 aluminum alloys.

Younger, Mandy S.; Eckelmeyer, Kenneth Hall

2007-11-01

334

Fracture of iron aluminide alloys  

SciTech Connect

Five heats of iron aluminide alloys have been prepared, and their impact fracture properties compared to FA-129 iron aluminide. The first was a simple ternary alloy of iron, aluminum, and chromium to match the FA-129 composition. The second was similar but with additions of zirconium and carbon. The third alloy had zirconium, carbon, niobium and molybdenum. Two heats were produced produced with reduced aluminum contents so that a disordered body-centered cubic structure would be present. The impact properties, microstructures, and fractography of these alloys were compared to FA-129. The ductile-to-brittle transition temperatures of all of the Fe{sub 3}Al alloys were similar, but the simple ternary alloy had a much higher upper-shelf energy. The reduced aluminum alloys had lower transition temperatures. The microstructures were, in general, coarse and anisotropic. The fracture processes were dominated by second-phase particles.

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

1992-01-01

335

Fracture of iron aluminide alloys  

SciTech Connect

Five heats of iron aluminide alloys have been prepared, and their impact fracture properties compared to FA-129 iron aluminide. The first was a simple ternary alloy of iron, aluminum, and chromium to match the FA-129 composition. The second was similar but with additions of zirconium and carbon. The third alloy had zirconium, carbon, niobium and molybdenum. Two heats were produced produced with reduced aluminum contents so that a disordered body-centered cubic structure would be present. The impact properties, microstructures, and fractography of these alloys were compared to FA-129. The ductile-to-brittle transition temperatures of all of the Fe{sub 3}Al alloys were similar, but the simple ternary alloy had a much higher upper-shelf energy. The reduced aluminum alloys had lower transition temperatures. The microstructures were, in general, coarse and anisotropic. The fracture processes were dominated by second-phase particles.

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

1992-08-01

336

Inherent Corrosion Resistance and Response to Cathodic Protection in Seawater of Recently Developed Stainless Steel Alloys.  

National Technical Information Service (NTIS)

Stainless steel alloys (24Ni-20Cr-6.5Mo, 26Cr-1M0, 22Cr-13Ni-5Mn, and Type 216 stainless steel) werre studied for inherent corrosion resistance in quiescent and slowly moving seawater. The response of these alloys to two levels of cathodic protection (mil...

T. J. Lennox M. H. Peterson

1976-01-01

337

Solid solution strengthened duct and cladding alloy D9B1  

Microsoft Academic Search

A modified AISI type 316 stainless steel is described for use in an atmosphere where the alloy will be subject to neutron irradiation. The alloy is characterized by its phase stability in both the annealed as well as cold work condition and above all by its superior resistance to radiation induced swelling. Graphical data is included to demonstrate the superior

Korenko; Michael K

1983-01-01

338

Extrusion Die Design and Process Simulation of High Strength Aluminium Alloy  

Microsoft Academic Search

Aluminium alloy 7075 is an excellent metal with the features of high strength and light weight. The solid extruded parts of AL 7075 are commonly used in the structure members of airplanes and bicycles. The seamless tubes of AL 7075 are also used, while tubes with welding line (seamed) are mainly made by the other types of aluminium alloy. This

Jinn-Jong Sheu; Yan-Hong Chen; Guan-Cheng Su

2011-01-01

339

Metallographic Evaluation of the Reactions Between Boronated Graphite and Fe-Ni-Cr Alloys.  

National Technical Information Service (NTIS)

The compatibility of boronated graphite with alloy 800H and type 316 stainless steel was evaluated metallographically after exposures at 700 and 810 exp 0 C for up to 10,000 h. At 700 exp 0 C, the principal reaction with both alloys was limited oxidation....

P. F. Tortorelli J. R. Mayotte T. J. Henson J. H. DeVan

1984-01-01

340

Effect of Zr addition on the aging behavior of A319 aluminum cast alloy  

Microsoft Academic Search

The structure, age hardening response, precipitate type and hardness of A319 cast aluminum alloy without and with zirconium addition were investigated. The as-solutionized and artificially-aged hardness values were higher for the Zr-containing alloy. This is believed to be a consequence of the precipitation of Al3Zr particles produced during sufficiently long solutionizing treatments.

P. Sepehrband; R. Mahmudi; F. Khomamizadeh

2005-01-01

341

Influence of Cutting Speed on Flank Temperature during Face Milling of Magnesium Alloy  

Microsoft Academic Search

Chip ignition is one of the important problems in cutting magnesium alloy due to cutting temperature rise which is mainly caused by the increase of cutting speed. In this paper, we measured the mean flank temperature through mounting two K-type thermocouples in workpiece of AM50A magnesium alloy. Effect of cutting speed on the temperature rise of tool flank was analyzed.

Junzhan Hou; Ning Zhao; Shaoli Zhu

2011-01-01

342

White golds: A review of commercial material characteristics & alloy design alternatives  

Microsoft Academic Search

White gold alloys became popular in the 1920s as alternatives to platinum in certain types of diamond-set jewellery. In this\\u000a article the author reviews the status of white gold alloy technology today and the efforts that have been made to improve\\u000a the properties of these materials.

Greg Normandeau

1992-01-01

343

Differences in growth mechanisms of oxide scales formed on ODS and conventional wrought alloys  

Microsoft Academic Search

The oxidation behavior in air of two ODS alloys, MA 754, a chromia former, and MA 956 an alumina-scale former, has been compared with that of conventional wrought model alloys with similar compositions. The main effects on scale properties of both oxide types due to oxide dispersions were found to be improved adherence, decreased growth rates, and enhanced selective oxidation.

W. J. Quadakkers; H. Holzbrecher; K. G. Briefs; H. Beske

1989-01-01

344

Effect of fetal calf serum on the corrosion behaviour of magnesium alloys  

Microsoft Academic Search

The corrosion behaviour of WE43 magnesium alloys using the mini cell system was studied. Voltammetry and impedance spectroscopy were applied to study on the one hand the effect of microstructure of the working electrode and on the other hand the effect of proteins in the electrolyte. Two types of alloy samples were produced (i) by permanent mould casting and (ii)

H. Hornberger; F. Witte; N. Hort; W.-D. Mueller

2011-01-01

345

Stress-Corrosion and Corrosion-Fatigue Susceptibility of High-Strength Aluminum Alloys.  

National Technical Information Service (NTIS)

The 'stress-corrosion-fatigue' performance of several high strength-aluminum alloys was investigated by tests of hydraulic cylinders and other types of specimens. Specimens were prepared from forgings and forging stock of alloys 2014-T6, 7075-T6, 7075-T73...

B. W. Lifka G. E. Nordmark J. G. Kaufman M. S. Hunter

1970-01-01

346

Permanent magnet alloy  

SciTech Connect

This patent describes a permanent magnet alloy consisting essentially of, in atomic percent, neodymium 8 to 15, thorium 6 to 10 with the total neodymium and thorium being within the range of 14 to 20, boron 4 to 14 and balance iron.

Narasimhan, K.S.V.L.; Ma, B.M.

1988-12-06

347

Nickel based casting alloy  

Microsoft Academic Search

A nickel base casting alloy containing 10 to 25 percent chromium, 3 to 8 percent manganese, 3 to 10 percent niobium, 0 to 3.5 percent aluminum, 0.5 to 2.0 percent beryllium which exhibits lower melting characteristics allowing enhanced compatibility to gypsum bonded investments.

A. P. Burnett; W. C. Bollinger

1985-01-01

348

Quinary metallic glass alloys  

DOEpatents

At least quinary alloys form metallic glass upon cooling below the glass transition temperature at a rate less than 10.sup.3 K/s. Such alloys comprise zirconium and/or hafnium in the range of 45 to 65 atomic percent, titanium and/or niobium in the range of 4 to 7.5 atomic percent, and aluminum and/or zinc in the range of 5 to 15 atomic percent. The balance of the alloy compositions comprise copper, iron, and cobalt and/or nickel. The composition is constrained such that the atomic percentage of iron is less than 10 percent. Further, the ratio of copper to nickel and/or cobalt is in the range of from 1:2 to 2:1. The alloy composition formula is: (Zr,Hf).sub.a (Al,Zn).sub.b (Ti,Nb).sub.c (Cu.sub.x Fe.sub.y (Ni,Co).sub.z).sub.d wherein the constraints upon the formula are: a ranges from 45 to 65 atomic percent, b ranges from 5 to 15 atomic percent, c ranges from 4 to 7.5 atomic percent, d comprises the balance, d.multidot.y is less than 10 atomic percent, and x/z ranges from 0.5 to 2.

Lin, Xianghong (Pasadena, CA); Johnson, William L. (Pasadena, CA)

1998-01-01

349

Quinary metallic glass alloys  

DOEpatents

At least quinary alloys form metallic glass upon cooling below the glass transition temperature at a rate less than 10{sup 3}K/s. Such alloys comprise zirconium and/or hafnium in the range of 45 to 65 atomic percent, titanium and/or niobium in the range of 4 to 7.5 atomic percent, and aluminum and/or zinc in the range of 5 to 15 atomic percent. The balance of the alloy compositions comprise copper, iron, and cobalt and/or nickel. The composition is constrained such that the atomic percentage of iron is less than 10 percent. Further, the ratio of copper to nickel and/or cobalt is in the range of from 1:2 to 2:1. The alloy composition formula is: (Zr,Hf){sub a}(Al,Zn){sub b}(Ti,Nb){sub c}(Cu{sub x}Fe{sub y}(Ni,Co){sub z}){sub d} wherein the constraints upon the formula are: a ranges from 45 to 65 atomic percent, b ranges from 5 to 15 atomic percent, c ranges from 4 to 7.5 atomic percent, d comprises the balance, d{hor_ellipsis}y is less than 10 atomic percent, and x/z ranges from 0.5 to 2.

Lin, X.; Johnson, W.L.

1998-04-07

350

Environmentally Assisted Cracking of Nickel Alloys  

SciTech Connect

Environmentally Assisted Cracking (EAC) is a general term that includes phenomena such as stress corrosion cracking (SCC), hydrogen embrittlement (HE), sulfide stress cracking (SSC), liquid metal embrittlement (LME), etc. EAC refers to a phenomenon by which a normally ductile metal looses its toughness (e.g. elongation to rupture) when it is subjected to mechanical stresses in presence of a specific corroding environment. For EAC to occur, three affecting factors must be present simultaneously. These include: (1) Mechanical tensile stresses, (2) A susceptible metal microstructure and (3) A specific aggressive environment. If any of these three factors is removed, EAC will not occur. That is, to mitigate the occurrence of EAC, engineers may for example eliminate residual stresses in a component or limit its application to certain chemicals (environment). The term environment not only includes chemical composition of the solution in contact with the component but also other variables such as temperature and applied potential. Nickel alloys are in general more resistant than stainless steels to EAC. For example, austenitic stainless steels (such as S30400) suffer SCC in presence of hot aqueous solutions containing chloride ions. Since chloride ions are ubiquitous in most industrial applications, the use of stressed stainless steels parts is seriously limited. On the other hand, nickel alloys (such as N10276) are practically immune to SCC in presence of hot chloride solutions and therefore an excellent alternative to replace the troubled stainless steels. Nonetheless, nickel alloys are not immune to other types of EAC. There are several environments (such as hot caustic and hot hydrofluoric acid) that may produce embrittlement in nickel alloys (Crum et al, 2000) (Table 1). The conditions where nickel alloys suffer EAC are highly specific and therefore avoidable by the proper design of the industrial components.

Rebak, R B

2004-02-06

351

Effects of the Wave Function Localization in AlInGaN Quaternary Alloys  

SciTech Connect

Using the first-principles band-structure method and the special quasirandom structures approach, the authors have investigated the band structure of random Al{sub x}In{sub y}Ga{sub 1-x-y}N quaternary alloys. They show that the wave functions of the band edge states are more localized on the InN sites. Consequently, the photoluminescence transition intensity in the alloy is higher than that in GaN. The valence band maximum state of the quaternary alloy is also higher than GaN with the same band gap, indicating that the alloy can be doped more easily as p-type.

Wang, F.; Li, S. s.; Xia, J. B.; Jiang, H. X.; Lin, J. Y.; Li, J.; Wei, S. H.

2007-01-01

352

Partial and integral enthalpies of mixing of Ag–Ga–Sn liquid alloys  

Microsoft Academic Search

A Calvet type calorimeter was used for measurement of partial and integral enthalpies of mixing of Ag–Ga–Sn alloys. The Ag–Ga binary alloys have been studied with 0alloys have been determined for xSn<0.35. The Ag–Ga–Sn ternary liquid alloys have been investigated at 803K along the

D. Li; S. Delsante; W. Gong; G. Borzone

2011-01-01

353

Effects of the wave function localization in AlInGaN quaternary alloys  

NASA Astrophysics Data System (ADS)

Using the first-principles band-structure method and the special quasirandom structures approach, the authors have investigated the band structure of random AlxInyGa1-x-yN quaternary alloys. They show that the wave functions of the band edge states are more localized on the InN sites. Consequently, the photoluminescence transition intensity in the alloy is higher than that in GaN. The valence band maximum state of the quaternary alloy is also higher than GaN with the same band gap, indicating that the alloy can be doped more easily as p-type.

Wang, Fei; Li, Shu-Shen; Xia, Jian-Bai; Jiang, H. X.; Lin, J. Y.; Li, Jingbo; Wei, Su-Huai

2007-08-01

354

Theoretical Studies of Hydrogen Storage Alloys.  

SciTech Connect

Theoretical calculations were carried out to search for lightweight alloys that can be used to reversibly store hydrogen in mobile applications, such as automobiles. Our primary focus was on magnesium based alloys. While MgH{sub 2} is in many respects a promising hydrogen storage material, there are two serious problems which need to be solved in order to make it useful: (i) the binding energy of the hydrogen atoms in the hydride is too large, causing the release temperature to be too high, and (ii) the diffusion of hydrogen through the hydride is so slow that loading of hydrogen into the metal takes much too long. In the first year of the project, we found that the addition of ca. 15% of aluminum decreases the binding energy to the hydrogen to the target value of 0.25 eV which corresponds to release of 1 bar hydrogen gas at 100 degrees C. Also, the addition of ca. 15% of transition metal atoms, such as Ti or V, reduces the formation energy of interstitial H-atoms making the diffusion of H-atoms through the hydride more than ten orders of magnitude faster at room temperature. In the second year of the project, several calculations of alloys of magnesium with various other transition metals were carried out and systematic trends in stability, hydrogen binding energy and diffusivity established. Some calculations of ternary alloys and their hydrides were also carried out, for example of Mg{sub 6}AlTiH{sub 16}. It was found that the binding energy reduction due to the addition of aluminum and increased diffusivity due to the addition of a transition metal are both effective at the same time. This material would in principle work well for hydrogen storage but it is, unfortunately, unstable with respect to phase separation. A search was made for a ternary alloy of this type where both the alloy and the corresponding hydride are stable. Promising results were obtained by including Zn in the alloy.

Jonsson, Hannes

2012-03-22

355

Study of the Relationship of Microporosity in Nickel-Based Alloys to Structural Hardening with Titanium and Aluminum During Precision Casting Etude de la Sensibilite a la Microporosite d'Alliages Base Nickel a Durissement Structural Par le Titane et l'Aluminium pour Fonderie de Precision.  

National Technical Information Service (NTIS)

The correlations between chemical composition, the solidification process, and the tendency towards microporosity were studied in controlled casting and cooling conditions, using eight types of INCONCEL 738 alloy and eight types of C263 alloy. A negative ...

F. Lavaud F. Wets G. Lesoult J. C. Lecomte P. Julien

1978-01-01

356

Consumable molding process for super alloys  

Microsoft Academic Search

A method of preparing a charge of super alloy material for use in metal casting is disclosed. Thin wall tubes consisting of one of the metallic elements of the alloy material, or an alloy of such element are provided. If an alloy tube is selected, all elements in the tube alloy must also be materials included in the overall formulation

Morykwas

1983-01-01

357

Casting Characteristics of Aluminum Die Casting Alloys  

Microsoft Academic Search

The research program investigates the casting characteristics of selected aluminum die casting alloys. Specifically, the alloys' tendencies towards die soldering and sludge formation, and the alloys' fluidity and machinability are evaluated. It was found that: When the Fe and Mn contents of the alloy are low; caution has to be taken against possible die soldering. When the alloy has a

Makhlouf M. Makhlouf; Diran Apelian

2002-01-01

358

Tensile bond strength of a composite resin cement for bonded prosthesis to various dental alloys.  

PubMed

The development of composite resin cements that chemically bond to dental alloys has improved the construction of resin-bonded prostheses. Composite resins can be selected for various situations, but specific clinical situations may require different alloys. This study evaluated the ability of a composite resin cement to bond to various dental alloys of different compositions. Ten pairs of disks for each alloy (two NiCr, two NiCrBe, one CuAl, one gold type IV, and one gold for metal ceramic) were bonded to a composite resin cement after air abrasion was performed with aluminum oxide. The disks were then rinsed in tap water and were ultrasonically cleaned in distilled water for 2 minutes. The tensile tests exhibited greater values for alloys ultrasonically cleaned, and the best results were recorded by NiCr and NiCrBe alloys. PMID:7473275

Rubo, J H; Pegoraro, L F

1995-09-01

359

Milling of gamma TiAl intermetallic alloys  

NASA Astrophysics Data System (ADS)

The work here exposed, is framed in the line of development of slight materials with good properties, used to reduction of weight in different components for the aviation and automotion. To use at high temperatures in slight pieces with high resistance. The superalloys of type Gamma TiAl is a attractive alternative to other titanium alloys, due to high relationship resistance/weigh and the resistance to the corrosion. This work, obtained the results in millin of three types of gamma TiAl alloys. Tools of integral hard metal are used, with different advances and cut speeds.

Beranoagirre, A.; López de Lacalle, L. N.

2009-11-01

360

Magnetically hard alnico 5 alloy with a mischmetal addition  

NASA Astrophysics Data System (ADS)

The addition of mischmetal (CeMM) to the Alnico 5 alloy of equiaxial grain structure in the amounts from 0.0 to 0.31 wt% and its effect on the magnetic properties, the crystal structure and on the type of non-metallic inclusions in the alloy has been studied. The addition of CeMM, in amounts within the examined limits, was found to cause a worsening of all magnetic properties of the Alnico 5 alloy, the greatest changes being observed in the maximum magnetic energy product (BH)max and the smallest in the coercive force Hc. CeMM also causes a considerable reduction in the size of grains. The main types of non-metallic inclusions in the Alnico 5 alloy with CeMM addition are: oxide(CeMM)2O3, oxysulphides (CeMM)2O2S and sulphides (CeMM)xSy type, on the edges of which occur titanium or manganese sulphides. For up to 0.16 wt% of CeMM the mean content of non-metallic inclusions in the alloy is decreasing, whereas it is markedly rising with the content of CeMM over 0.16 wt%. Also the mean size of inclusions is clearly smaller in the alloy with less than 0.16 wt% of CeMM than with higher contents of CeMM. A 0.16 wt% addition of CeMM significantly improves the susceptibility of Alnico 5 alloy to surface finishing treatment by grinding.

Szymura, S.

1983-05-01

361

Interfacial oxidations of pure titanium and titanium alloys with investments.  

PubMed

External oxides of a commercially pure titanium (cpTi), Ti6Al4V alloy, and an experimental beta-type titanium alloy (Ti 53.4 wt%, Nb 29 wt%, Ta 13 wt%, and Zr 4.6 wt%) were characterized after heating to 600, 900, 1150, and 1400 degrees C in contact with three types of investments (alumina cement, magnesia cement, and phosphate-bonded) in air. XRD studies demonstrated that MgO, Li2TiO3 and/or Li2Ti3O7 were formed through reactions with the metal and the constituents in the magnesia cement-investment after heating to 900, 1150, and 1400 degrees C. Except for these conditions, TiO2 (rutile) was only formed on cpTi. For titanium alloys, the other components apart from Ti also formed simple and complex oxides such as Al2O3 and Al2TiO5 on Ti6Al4V, and Zr0.25Ti0.75Nb2O7 on the beta-type titanium alloy. However, no oxides containing V or Ta were formed. These results suggest that the constituents of titanium alloys reacted with the investment oxides and atmospheric oxygen to form external oxides due to the free energy of oxide formation and the concentration of each element on the metal surface. PMID:11816365

Ban, S; Watanabe, T; Mizutani, N; Fukui, H; Hasegawa, J; Nakamura, H

2000-12-01

362

Laser surface alloying of silicon into aluminum casting alloys  

Microsoft Academic Search

Aluminum alloys that are easily castable tend to have lower silicon content, and hence, lower wear resistance. The use of laser surface alloying to improve the surface wear resistance of 319 and 320 aluminum alloys was examined. A silicon layer was painted onto the surface to be treated. A high power pulsed Nd:yttrium-aluminum-garnet laser with fiber-optic beam delivery was used

Zhiyue Xu; Keng H. Leong; Paul G. Sanders

2000-01-01

363

Alloy design concepts for refined gamma titanium aluminide based alloys  

Microsoft Academic Search

The influence of the Al content and the addition of further alloying elements on the cast microstructure of ?(TiAl)+?2(Ti3Al) alloys has been examined. The results show that particularly fine and homogeneous microstructures without strong segregation can be obtained for certain alloy compositions solidifying through the ? phase. This behavior can be attributed to the avoidance of peritectic solidification and to

R. M. Imayev; V. M. Imayev; M. Oehring; F. Appel

2007-01-01

364

Transpassive dissolution of Ni–Cr alloys in sulphate solutions—comparison between a model alloy and two industrial alloys  

Microsoft Academic Search

The application of a general model for the transpassive dissolution mechanism of binary Ni-based alloys to industrial alloys, Alloy 600 and Alloy C276, containing Ni, Cr, Fe and Mo, in 1 M sulphate solutions at pH 0 and 5 is described. A comparison of the electrochemical behaviour of these two alloys to a binary Ni–15%Cr alloy is also included. The

Martin Bojinov; Gunilla Fabricius; Petri Kinnunen; Timo Laitinen; Kari Mäkelä; Timo Saario; Göran Sundholm; Kirsi Yliniemi

2002-01-01

365

Reduction in Defect Content of ODS Alloys  

SciTech Connect

The work detailed within this report is a continuation of earlier work carried out under contract number 1DX-SY382V. The earlier work comprises a literature review of the sources and types of defects found principally in Fe-based ODS alloys as well as experimental work designed to identify defects in the prototype ODS-Fe{sub 3}Al alloy, deduce their origins and to recommend methods of defect reduction. The present work is an extension of the experimental work already reported and concentrates on means of reduction of defects already identified rather than the search for new defect types. This report also includes work regarding the manipulation of grain structures via deformation processing and further results gathered during powder separation trials involving the separation of different metallic powders in terms of their differing densities. The scope and objectives of the present work were laid out in the technical proposal ''Reduction in Defect Content in ODS Alloys-IV''. All the work proposed in the ''Statement of Work'' section of the technical proposal has been carried out except for some of that dependent on the acquisition of materials from other sources. However, wherever omissions from the ''Plan of Action'' detailed in the ''Statement of Work'' have occurred due to lack of suitable materials, other related experimental work has been devised to fill the gaps where possible. All work extra to the ''Statement of Work'' falls within the context of an ODS-Fe{sub 3}Al alloy of improved overall quality and potential creep performance in the consolidated form. The outturn of the experimental work performed is reported in the following sections.

Ritherdon, J

2003-11-17

366

Filler metal alloy for welding cast nickel aluminide alloys  

DOEpatents

A filler metal alloy used as a filler for welding east nickel aluminide alloys contains from about 15 to about 17 wt. % chromium, from about 4 to about 5 wt. % aluminum, equal to or less than about 1.5 wt. % molybdenum, from about 1 to about 4.5 wt. % zirconium, equal to or less than about 0.01 wt. % yttrium, equal to or less than about 0.01 wt. % boron and the balance nickel. The filler metal alloy is made by melting and casting techniques such as are melting the components of the filler metal alloy and east in copper chill molds.

Santella, Michael L. (Knoxville, TN); Sikka, Vinod K. (Oak Ridge, TN)

1998-01-01

367

Filler metal alloy for welding cast nickel aluminide alloys  

DOEpatents

A filler metal alloy used as a filler for welding cast nickel aluminide alloys contains from about 15 to about 17 wt. % chromium, from about 4 to about 5 wt. % aluminum, equal to or less than about 1.5 wt. % molybdenum, from about 1 to about 4.5 wt. % zirconium, equal to or less than about 0.01 wt. % yttrium, equal to or less than about 0.01 wt. % boron and the balance nickel. The filler metal alloy is made by melting and casting techniques such as are melting the components of the filler metal alloy and cast in copper chill molds. 3 figs.

Santella, M.L.; Sikka, V.K.

1998-03-10

368

A Review on High-Speed Machining of Titanium Alloys  

NASA Astrophysics Data System (ADS)

Titanium alloys have been widely used in the aerospace, biomedical and automotive industries because of their good strength-to-weight ratio and superior corrosion resistance. However, it is very difficult to machine them due to their poor machinability. When machining titanium alloys with conventional tools, the tool wear rate progresses rapidly, and it is generally difficult to achieve a cutting speed of over 60m/min. Other types of tool materials, including ceramic, diamond, and cubic boron nitride (CBN), are highly reactive with titanium alloys at higher temperature. However, binder-less CBN (BCBN) tools, which do not have any binder, sintering agent or catalyst, have a remarkably longer tool life than conventional CBN inserts even at high cutting speeds. In order to get deeper understanding of high speed machining (HSM) of titanium alloys, the generation of mathematical models is essential. The models are also needed to predict the machining parameters for HSM. This paper aims to give an overview of recent developments in machining and HSM of titanium alloys, geometrical modeling of HSM, and cutting force models for HSM of titanium alloys.

Rahman, Mustafizur; Wang, Zhi-Gang; Wong, Yoke-San

369

High Bs nanocrystalline alloys with high amorphous-forming ability  

NASA Astrophysics Data System (ADS)

The soft magnetic property and the structure of the new type nanocrystalline Fe-(P,B,Si,Nb,Cu) alloy with high Fe content about 80 at. % have been investigated. In this paper Fe77.9P3B14Nb5Cu0.1 alloy has a supercooled liquid region (?Tx) of 33 K defined by the difference between the glass transition temperature (Tg) and crystallization temperature (Tx), which would be relating to the high glass-forming ability leading a thickness of 140 ?m melt-spun ribbon with a glassy phase. The Fe80.9P2B10Si2Nb5Cu0.1 alloy with the higher Fe content can be melt spun into the thick ribbon with thickness of 65 ?m due to rather large amorphous-forming ability. In addition, a homogeneous nanostructure composed of ?-Fe grain with around 15 nm in diameter was realized after crystallization, and the nanostructured alloy exhibits the high Bs of 1.55 T and the low coercivity (Hc) of 4.6 A/m. The Bs and the glass or amorphous-forming ability of the alloys are superior to those for typical nanocrystalline. Therefore, the miniaturization and the realization of higher efficiency of power supply circuits in electric devices are able to be expected using these nanocrystalline Fe-(P,B,Si,Nb,Cu) alloys.

Urata, A.; Matsumoto, H.; Sato, S.; Makino, A.

2009-04-01

370

Positron lifetime studies of decomposition in 2024 (Al-Cu-Mg) and 7010 (Al-Zn-Cu-Mg) alloys  

SciTech Connect

In the current paper, the decomposition behavior of the engineering alloys 2024 (Al-Cu-Mg) and 7010 (Al-Zn-Cu-Mg) is studied using positron lifetime measurements. Positrons probe open volume defects such as vacancies and dislocations. However, they may also be used to investigate coherent zones and incoherent precipitates. In order to understand the rather complicated precipitation sequences and the response of positrons to different type of precipitates occurring in 2024 and 7010 alloys, binary and ternary laboratory alloys were also investigated under the same experimental conditions as the engineering alloys. The interpretations of the results are based on experiences of the group from extensive positron studies of laboratory alloys such as Al-Zn, Al-Zn-Mg, Al-Cu, and further Al alloys (see also the review (4)). Their collected results are shown as lifetimes and curve-shape parameters S of the electron-positron momentum distribution curves characteristic for different precipitates in Al alloys.

Dlubek, G. [ITA Inst. fuer Innovative Technologien GmbH, Halle (Germany)]|[Martin-Luther-Univ. Halle-Wittenberg, Halle (Germany). Fachbereich Physik; Lademann, P.; Krause, H.; Krause, S.; Unger, R. [Martin-Luther-Univ. Halle-Wittenberg, Halle (Germany). Fachbereich Physik

1998-09-04

371

Corrosion of Zirconium and Zirconium Alloys.  

National Technical Information Service (NTIS)

Contents: The influence of alloying elements and heat treatment on the corrosion resistance of zirconium in water and steam; Theories on the mechanism of corrosion of zirconium and its alloys; Factors influencing hydrogen pick-up by zirconium alloys; The ...

B. G. Parfenov V. V. Gerasimov G. I. Venediktova

1969-01-01

372

Two phase titanium aluminide alloy  

DOEpatents

A two-phase titanic aluminide alloy having a lamellar microstructure with little intercolony structures. The alloy can include fine particles such as boride particles at colony boundaries and/or grain boundary equiaxed structures. The alloy can include alloying additions such as .ltoreq.10 at % W, Nb and/or Mo. The alloy can be free of Cr, V, Mn, Cu and/or Ni and can include, in atomic %, 45 to 55% Ti, 40 to 50% Al, 1 to 5% Nb, 0.3 to 2% W, up to 1% Mo and 0.1 to 0.3% B. In weight %, the alloy can include 57 to 60% Ti, 30 to 32% Al, 4 to 9% Nb, up to 2% Mo, 2 to 8% W and 0.02 to 0.08% B.

Deevi, Seetharama C. (Midlothian, VA); Liu, C. T. (Oak Ridge, TN)

2001-01-01

373

TERNARY ALLOY-CONTAINING PLUTONIUM  

DOEpatents

Ternary alloys of uranium and plutonium containing as the third element either molybdenum or zirconium are reported. Such alloys are particularly useful as reactor fuels in fast breeder reactors. The alloy contains from 2 to 25 at.% of molybdenum or zirconium, the balance being a combination of uranium and plutonium in the ratio of from 1 to 9 atoms of uranlum for each atom of plutonium. These alloys are prepared by melting the constituent elements, treating them at an elevated temperature for homogenization, and cooling them to room temperature, the rate of cooling varying with the oomposition and the desired phase structure. The preferred embodiment contains 12 to 25 at.% of molybdenum and is treated by quenching to obtain a body centered cubic crystal structure. The most important advantage of these alloys over prior binary alloys of both plutonium and uranium is the lack of cracking during casting and their ready machinability.

Waber, J.T.

1960-02-23

374

Diffusion welding of hard alloys  

Microsoft Academic Search

1.The hot pressing method, which is characterized by induction heating in graphite dies, can be used for the diffusion welding of tungsten-cobalt hard alloys and the “baking-on” of new hard-alloy layers consisting of hard-alloy powder mixtures.2.Mechanical tests have shown that the strength secured by means of diffusion welding at 1400° according to the proposed method approaches the strength of the

K. S. Gerasimenko; S. I. Spirina

1967-01-01

375

Shape memory alloy actuator  

DOEpatents

An actuator for cycling between first and second positions includes a first shaped memory alloy (SMA) leg, a second SMA leg. At least one heating/cooling device is thermally connected to at least one of the legs, each heating/cooling device capable of simultaneously heating one leg while cooling the other leg. The heating/cooling devices can include thermoelectric and/or thermoionic elements.

Varma, Venugopal K. (Knoxville, TN)

2001-01-01

376

Cobalt base alloy  

Microsoft Academic Search

A cobalt base alloy having a superior high-temperature strength and high-temperature ductility, containing, by weight, 0.15 to 2% carbon, less than 2% silicon, less than 2% manganese, 5 to 15% nickel, 18 to 35% chromium, 3 to 15% tungsten, 0.003 to 0.1% boron, 0.01 to 1% niobium, 0.01 to 1% zirconium, less than 10% iron, less than 1% tantalum, less

Y. Fukui; T. Kashimura

1984-01-01

377

Amorphous magnetic alloy  

SciTech Connect

An amorphous magnetic alloy is described having the formula Co /SUB x/ M /SUB y/ B /SUB z/ wherein M is zirconium, hafnium and/or titanium. When M is hafnium or zirconium 70x80, 8y15 and 10z16. When M is titanium, 70x72, 16y25 and 4z10. When M is hafnium together with titanium and/or zirconium, 70x80, 8y20 and 5z16.

Kanehira, J.

1984-04-03

378

Duct and cladding alloy  

DOEpatents

An austenitic alloy having good thermal stability and resistance to sodium corrosion at 700.degree. C. consists essentially of 35-45% nickel 7.5-14% chromium 0.8-3.2% molybdenum 0.3-1.0% silicon 0.2-1.0% manganese 0-0.1% zirconium 2.0-3.5% titanium 1.0-2.0% aluminum 0.02-0.1% carbon 0-0.01% boron and the balance iron.

Korenko, Michael K. (Rockville, MD)

1983-01-01

379

Corrosion behavior of cast and forged cobalt-based alloys for double-alloy joint endoprostheses.  

PubMed

An ideal combination of mechanical and corrosion properties of long-term implants such as joint endoprostheses has yet to be found. Besides being resistant to pitting and crevice attack, which can lead to corrosion fatigue and stress corrosion cracking failures, the implant material must be highly resistant to wear and abrasion. Two cobalt-based alloys, wrought CoNiMoTi and air-cast CoCrMo, were subjected to a number of selected in vitro electrochemically and chemically accelerated corrosion tests in chloride-containing solutions with wrought AISI-316L used as a reference alloy. A limited number of immersion tests in FeCl3 and acidified FeCl3 solutions were also conducted. It is found that the mechanical properties of wrought CoNiCrMoTi alloy qualify it as a substitute for cast CoCrMo alloy and wrought AISI-316L in anchorage shaft production for all types of joint endoprostheses. Wrought CoNiCrMoTi has a higher resistance to fatigue cracking compared with cast CoCrMo and is as resistant to selective corrosion phenomena such as stress corrosion cracking. PMID:701305

Süry, P; Semlitsch, M

1978-09-01

380

Magneto-clastic distortions in Heusler alloys  

NASA Astrophysics Data System (ADS)

Magnetic and neutron scattering experiments have been carried out on a new series of Heusler alloys based on the composition (Au1Pd2-x)MnIn. A magnetic moment of ~4 ?B is confined to the manganese atoms and for x < 1.4 the compounds order antiferromagnetically below ~ 150 K. Dependent upon composition, three distint structures are observed: antiferromagnetism of type I. II and IIIA. This represents the first observation of type I ordering in a Heusler system. The configurational symmetry associated with these structures has a well-defined anisotropy, producing a distinct lattice distortion in the case of types I and III order. There has been no observation of any lattice distortion associated with the onset of type II antiferromagnetism. The structural distortion, which depends upon the size of the Mn moment, has been investigated as a function of temperature.

Jassim, I. K.; Neumann, K.-U.; Visser, D.; Webster, P. J.; Ziebeck, K. R. A.

1992-02-01

381

Corrosion investigation of multilayered ceramics and experimental nickel alloys in SCWO process environments.  

National Technical Information Service (NTIS)

A corrosion investigation was done at MODAR, Inc., using a supercritical water oxidation (SCWO) vessel reactor. Several types of multilayered ceramic rings and experimental nickel alloy coupons were exposed to a chlorinated cutting oil TrimSol, in the SCW...

K. M. Garcia R. Mizia

1995-01-01

382

Copper and Copper Alloy Powders. Seminar Held on 18th December 1976.  

National Technical Information Service (NTIS)

This report contains the following papers: Types, Properties and Uses of Copper Powder; Production of Copper & Copper Alloy Powders for General Engineering Applications; Bronze Powders; Atomized Copper and Copper Based Powders; Process and Equipment for t...

1976-01-01

383

Determination of Feasibility of Applying Computer Analysis of Titanium Alloy Microstructures to Quality Control.  

National Technical Information Service (NTIS)

Two types of microstructure samples were examined for the Ti-6Al-2Sn-4Zr-6Mo titanium alloy under consideration. These included normal preparation of specimens and nondestructive preparation through electropolishing and replication. In total, 53 photomicr...

A. Dekaney L. E. Guthrie

1973-01-01

384

Glass formation in mechanically alloyed transition-metal-Zr alloys  

Microsoft Academic Search

A large number of TM-Zr alloys (where TM is a transition metal) have been produced by mechanical alloying from crystalline powders of the elements. The first milled products showed a layered microstructure of the powder particles, which became finer with increasing milling time. Longer milling led to amorphous powder. The formation of amorphous TM-Zr (TM ? Cu, Ni, Co, Fe,

E. Hellstern; L. Schultz

1987-01-01

385

Alloy Design for Nickel-Base Super Alloy Single Crystals.  

National Technical Information Service (NTIS)

The purpose of this study is to develop high creep strength Nickel-base superalloys suitable for single crystal. A computer-aided alloy design system previously developed in NRIM is applied for this purpose. Ten alloys designed contained 5 - 10 Cr, 8 - 19...

T. Yamagata

1984-01-01

386

Structure and properties of rapidly-solidified iron-platinum and iron-palladium alloys  

SciTech Connect

Fe-Pt and Fe-Pd alloys can develop an attractive combination of hard magnetic properties similar to the Co-Pt permanent magnet alloys. This family of alloys derives its properties from CuAuI (LI{sub 0})-type ordering and exhibits a polytwinned microstructure which is expected to have a strong influence on the domain structure and mechanism of coercivity. In this study rapid solidification techniques and systematic heat treatment have been employed to vary the microstruture of equiatomic Fe-Pt and Fe-Pd alloys to gain a better understanding of the fundamental processes controlling the magnetic properties of the genre of alloy. Preliminary results on the Fe-Pd alloy indicate that the magnetically hardened material is fully ordered and exhibits a well-developed polytwinned state. Melt-spinning was found to enhance the coercivity compared to a bulk alloy and it is suggested that this change in properties is related to microstructural refinement within the polytwinned state. The initial results on the Fe-Pt alloy indicate that the details of the mechanism of hardening in this alloy may be somewhat different than in the Fe-Pd system although both develop the polytwinned state after prolonged aging.

Zhang, B.; Soffa, W.A. (Pittsburgh Univ., PA (USA). Dept. of Materials Science and Engineering)

1990-09-01

387

Cellular response to metallic ions released from nickel-chromium dental alloys.  

PubMed

Concerns exist over the potential release of elevated levels of metal ions such as Ni and Be from Ni-Cr dental casting alloys, due to their susceptibility to accelerated corrosion. In this investigation, we evaluated the release of metal ions from four commercial Ni-Cr alloys, representing a range of compositions, in three-day cell culture tests. Metal ion release, as measured by atomic absorption spectroscopy, was correlated to changes in cellular morphology, viability, and proliferation. The results showed that the test alloys and their corrosion products did not affect cellular morphology or viabilities, but did decrease cellular proliferation. The types and amounts of metal ions released, which corresponded to the alloys' reported surface and corrosion properties, also correlated to observed decreases in cellular proliferation after 72 h. Neptune, which caused the smallest decrease in cellular proliferation as compared with control cells, released the lowest amount of corrosion products, due to its corrosion-resistant, high-Cr-Mo-containing, homogeneous surface oxide. The other test alloys, which were susceptible to accelerated corrosion processes, released higher levels of metal ions that correlated to larger decreases in thymidine incorporation. Metal ion levels increased with test time for all alloys but were not proportional to bulk alloy compositions. Ni ions were released at slightly higher than bulk alloy compositions, while Be was released at from four to six times that of bulk alloy compositions. The elevated release of Be ions was associated with reduced cellular proliferation.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7560409

Bumgardner, J D; Lucas, L C

1995-08-01

388

Fireside corrosion testing of candidate superheater tube alloys, coatings, and claddings  

SciTech Connect

Fireside corrosion, caused by liquid alkali-iron trisulfates, has been an obstacle to higher steam temperatures and to efficient utilization of high-sulfur coals. Tests simulating the environment in the superheater bank of a pulverized-coal-fired boiler were conducted on several promising new alloys and claddings. Alloys were exposed to a variety of synthetic ash and simulated flue gas compositions at 650 and 700{degrees}C for times ranging up to 800 hours. Included in the testing program were new high-chromium/high-nickel alloys, modified commercial alloys, lean stainless steels (modified Type 316) clad with high-chromium/high-nickel alloys, and intermetallic aluminides. Thickness loss measurements indicated that resistance to attach improved with increasing chromium level. Silicon and aluminum were also helpful in resisting attack, while molybdenum was detrimental to the resistance of the alloys to attack. Three different attack modes were observed on the alloys tested. Alloys with low resistance to attack exhibited uniform wastage, while pitting was observed in more resistant alloys. In addition to surface fluxing by molten alkali-iron trisulfates, subsurface sulfur penetration and intergranular attack also occurred.

Van Weele, S. (Foster Wheeler Development Corp., Livingston, NJ (United States))

1991-08-01

389

Fireside corrosion testing of candidate superheater tube alloys, coatings, and claddings. Final report  

SciTech Connect

Fireside corrosion, caused by liquid alkali-iron trisulfates, has been an obstacle to higher steam temperatures and to efficient utilization of high-sulfur coals. Tests simulating the environment in the superheater bank of a pulverized-coal-fired boiler were conducted on several promising new alloys and claddings. Alloys were exposed to a variety of synthetic ash and simulated flue gas compositions at 650 and 700{degrees}C for times ranging up to 800 hours. Included in the testing program were new high-chromium/high-nickel alloys, modified commercial alloys, lean stainless steels (modified Type 316) clad with high-chromium/high-nickel alloys, and intermetallic aluminides. Thickness loss measurements indicated that resistance to attach improved with increasing chromium level. Silicon and aluminum were also helpful in resisting attack, while molybdenum was detrimental to the resistance of the alloys to attack. Three different attack modes were observed on the alloys tested. Alloys with low resistance to attack exhibited uniform wastage, while pitting was observed in more resistant alloys. In addition to surface fluxing by molten alkali-iron trisulfates, subsurface sulfur penetration and intergranular attack also occurred.

Van Weele, S. [Foster Wheeler Development Corp., Livingston, NJ (United States)

1991-08-01

390

Modification of alloy surfaces using pulsed energy  

SciTech Connect

A method to improve the quality and bonding of surface coatings is explored. The method involves application of radio frequency (rf) induction heating to coated metallic surfaces. By tailoring the rf frequency, depth of induction heating penetration can be controlled. Total heat input is a function of the duration of rf power application. Induction heating using high frequencies and short pulses provides a mechanism for controlled penetration heating. The objective of this project was to demonstrate coating consolidation and metallurgical alloying of an inductively coupled coating into the substrate material, without affecting the bulk substrate material properties. A metallurgically alloyed coating to substrate interface improves coating adherence and can provide graded properties in the interface region. Coating consolidation serves to improve the coating integrity through the elimination of porosity and cracks. This report details experimental studies to place palladium, nickel and chromium coatings over substrates of Inconel alloys 182 and 600, and Type 316NG stainless steel. Continuously bonded coatings of palladium were produced. Preliminary thermal cycling studies indicate coating stability.

Clark, R.A. (Failure Analysis Associates, Inc., Redmond, WA (United States))

1991-10-01

391

Fatigue strength of welded joints in 6N01 aluminium alloy extrusions  

Microsoft Academic Search

In this paper, the fatigue strength of welded joints in 6N01 aluminium alloy extrusions is discussed. Low copper content (?0.02%) alloys were chosen, considering corrosion resistance in sea water. Two series of specimens were prepared. One had two longitudinal stiffeners welded on both sides of the main plate (L?TYPE), and the other a non?load carrying fillet welded cruciform joint (T?TYPE).

K. Matsuoka; S. Chiaki; T. Uemura; K. Kamata

1994-01-01

392

The effect of grain size on environmental embrittlement of Co[sub 3]Ti alloy  

SciTech Connect

The environmental embrittlement of L1[sub 2]-type Co[sub 3]Ti ordered alloy has been studied by the present authors from various points of view. In this study, the effect of grain size on the moisture-induced embrittlement of L1[sub 2]-type Co[sub 3]Ti ordered alloy is investigated at room temperature by tensile test and fractography. Embrittlement/ductility property is assessed as functions of grain size, strain rate and environmental media.

Takasugi, T.; Hanada, S. (Tohoku Univ., Sendai (Japan). Inst. for Materials Research)

1999-06-18

393

Robust control for shape memory alloy micro-actuators based flap positioning system  

Microsoft Academic Search

In this paper, the control approach for a flap positioning based shape memory alloy micro-actuator is addressed. The challenge here are to model the saturation-type hysteresis in the shape memory alloy actuator, and design the controller to mitigate the effect of hysteresis and ensure the system performance. In this paper, the saturation-type hysteresis nonlinearities are represented by the generalized Prandtl-Ishlinskii

Ying Feng; Camille Alain Rabbath; Henry Hong; Mohammad Al Janaideh; Chun-Yi Su

2010-01-01

394

Recent development in aluminium alloys for aerospace applications  

Microsoft Academic Search

Driven by the increasing requirements from aircraft producers, Hoogovens Aluminium Rolled Products GmbH, together with Hoogovens Research & Development, has enhanced the property combinations of their aircraft materials. For these types of material, optimised processing routes as well as new alloy chemistries have been investigated. Whilst retaining the strength levels required by the aerospace industry, new processing routes offer major

A Heinz; A Haszler; C Keidel; S Moldenhauer; R Benedictus; W. S Miller

2000-01-01

395

Wettability of carbon by aluminum and aluminum alloys  

Microsoft Academic Search

Wetting (both equilibrium contact angle and spreading kinetics) of aluminum and aluminum alloys with silicon and titanium on carbon substrates is investigated as a function of temperature and carbon microstructure. Experiments are carried out by the sessile drop technique under high vacuum, in the range from 1023 to 1250K. Three different types of carbon substrates are examined: vitreous carbon, pyrolytic

K. Landry; S. Kalogeropoulou; N. Eustathopoulos

1998-01-01

396

Effect of Sulfide Minerals on Ferrous Alloy Grinding Media Corrosion.  

National Technical Information Service (NTIS)

The U.S. Bureau of Mines determined the effect of common sulfide minerals on the corrosion rates of various types of ferrous alloy grinding media. Data obtained from the study will aid in determining the contribution of any electrochemical reactions betwe...

A. E. Isaacson

1989-01-01

397

Loss of Alloy in Cast Restorations Fabricated by Dental Students.  

ERIC Educational Resources Information Center

|A study investigated the quantity of alloy lost in the fabrication of three types of cast restoration by dental students, and identified the proportion of loss at each of the four principal stages of the fabrication process. Suggestions for reducing metal loss and related costs in dental schools are offered. (MSE)|

Soh, George

1991-01-01

398

Creep properties of phosphorus + boron-modified alloy 718  

SciTech Connect

Creep-rupture testing of modified alloy 718 has confirmed the beneficial effect of optimum additions of P and B. Activation energies and creep exponent analyses suggest some type of pinning mechanism is involved in this strengthening. However, the exact mechanism of this improvement is still unclear.

McKamey, C.G.; Carmichael, C.A. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.; Cao, W.D.; Kennedy, R.L. [Allvac, Monroe, NC (United States)

1998-01-06

399

Titanium aluminide formation in Ti implanted aluminium alloy  

Microsoft Academic Search

Ion implantation has been extensively used for modifying the surfaces of engineering materials. In the present report, the implantation of type 6061 aluminium alloy with Ti ions has been investigated as a function of dose and substrate temperature. Retained doses in the range 0.8?6 × 1017 ions cm?2 were studied in order to examine the effect of Ti concentration on

S. T. Knight; P. J. Evans; M. Samandi

1996-01-01

400

Titanium aluminide formation in Ti implanted aluminium alloy  

Microsoft Academic Search

Ion implantation has been extensively used for modifying the surfaces of engineering materials. In the present report, the implantation of type 6061 aluminium alloy with Ti ions has been investigated as a function of dose and substrate temperature. Retained doses in the range 0.8-6 × 1017 ions cm-2 were studied in order to examine the effect of Ti concentration on

P. J. Evans; S. T. Knight; M. Samandi

1996-01-01

401

Creep Properties of Phosphorus+Boron-Modified Alloy 718  

Microsoft Academic Search

Creep-rupture testing of modified alloy 718 has confirmed the beneficial effect of optimum additions of P and B. Activation energies and creep exponent analyses suggest some type of pinning mechanism is involved in this strengthening. However, the exact mechanism of this improvement is still unclear.

C. G. McKamey; C. A. Carmichael; W. D. Cao; R. L. Kennedy

1998-01-01

402

Effects of SOâ scrubber environments on alloy corrosion. Final report  

Microsoft Academic Search

A laboratory study was performed to evaluate the corrosion behavior of titanium grade 2, Type 317L stainless steel and Hastelloy Alloy G3 in complex simulated flue gas desulfurization (FGD) environments. The corrosion behavior was evaluated using potentiodynamic polarization techniques and the simulated FGD solutions were selected based upon a statistical experimental design. The results of the laboratory experiments indicated that

G. H. Koch; N. G. Thompson; J. M. Spangler

1986-01-01

403

Relation between physical properties and phase transformations in alloys of the Ti?W?Zr?Al system  

Microsoft Academic Search

Phase transformations in titanium alloys cannot always be determined by methods of diffraction analysis because the type of\\u000a structure depends considerably on the form of heat treatment and the alloying elements. It is more expedient to judge the\\u000a structural state and phase transformations in these alloys be the changes in their physical and mechanical properties in relation\\u000a to the composition

É. I. Illarionov

1997-01-01

404

Comparative study of forging parameters on microstructures and properties between Aluminum alloys Al6063 and Al7075  

Microsoft Academic Search

This research were designed and created hot forging moulds of Aluminum alloys to investigate the effect of heating influence on machine qualifications of Aluminum alloys and know the suitable conditions of hot forging. The experimental variable was forging temperature and analyzed the experiment results for determined the suitable condition in hot forging on two types Aluminum alloysAlSi1Mg:Al6063 and AlZn5.5MgCuAl7075. The

S. SOPHA; S. NANSAARNG

2007-01-01

405

Role of replacement of Sb with Al in the phase transformation of Ni-Mn-Sb alloys  

NASA Astrophysics Data System (ADS)

Ferromagnetic shape memory alloy with composition Ni50Mn34Sb8Al8 was prepared and its structural transformation temperatures were determined. The replacement of Sb with Al in this alloy led to increase in transition temperature but more interestingly, the low temperature magnetic behavior shows spin glass type nonergodic behavior, in contrast to simple ferromagnetic like other similar alloys. Resistivity measurements confirmed the structural transformation temperatures.

Agarwal, Sandeep; Mukhopadhyay, P. K.

2013-06-01

406

The optimal condition of acidic electroless copper plating method for Ti, Zr-based hydrogen storage alloys for electrode use  

Microsoft Academic Search

An acidic electroless copper plating using HF for titanium and zirconium-based hydrogen storage alloys shows a significant improvement in activation and discharge capacity of the alloy electrodes even though the plating process is simple. In this paper, the optimal conditions of this acidic electroless copper plating have been investigated for Ti, Zr-based AB2-type alloy powders for a negative electrode of

S. J. Choi; J. Choi; C. Y. Seo; C. N. Park

2003-01-01

407

Investigation into the metallurgical aspects of joining rapidly-solidified aluminum alloys. Final report, September 1984December 1987  

Microsoft Academic Search

Research performed during this program demonstrated that the metastable microstructures upon which rapidly-solidified, powder metallurgy (RS\\/PM) aluminum alloys depend for their unique mechanical properties can be both recreated using rapid-solidification fusion-welding processes and\\/or retained using solid-state welding processes. Alloys investigated included Al-Fe-X dispersoid-type compositions developed for superior elevated-temperature properties and Al-Li-X alloys developed for high strength and modulus and low

Baeslack

1988-01-01

408

Welding Metallurgy of Alloy HR-160  

SciTech Connect

The solidification behavior and resultant solidification cracking susceptibility of autogenous gas tungsten arc fusion welds in alloy HR-160 was investigated by Varestraint testing, differential thermal analysis, and various microstructural characterization techniques. The alloy exhibited a liquidus temperature of 1387 {deg}C and initiated solidification by a primary L - {gamma} reaction in which Ni, Si, and Ti segregated to the interdendritic liquid and Co segregated to the {gamma} dendrite cores. Chromium exhibited no preference for segregation to the solid or liquid phase during solidification. Solidification terminated at {approx} 1162 {deg}C by a eutectic-type L - [{gamma}+ (Ni,Co){sub 16}(Ti,Cr){sub 6}Si{sub 7}] reaction. The (Ni,Co){sub 16}(Ti,Cr){sub 6}Si{sub 7} phase is found to be analogous to the G phase which forms in the Ni-Ti-Si and Co-Ti-Si ternary systems, and similarities are found to exist between the solidification behavior of this commercial multicomponent alloy and the simple Ni-Si and Ni-Ti binary systems. Reasonable agreement is obtained between the calculated and measured volume percent of the [{gamma} +(Ni,Co){sub l6}(Ti,Cr){sub 6}Si{sub 7}] eutectic-typr constituent with the Scheil equation using experimentally determined k values for Si and Ti from electron microprobe data. The alloy exhibited a very high susceptibility to solidification cracking in the Varestraint test. This is attributed to a large solidification temperature range of 225 {deg}C and the presence of 2 to 5 vol% solute rich interdendritic liquid which preferentially wets the grain boundaries and interdendritic regions.

DuPont, J.N.; Michael, J.R.; Newbury, B.D.

1999-05-28

409

Atomic engineering of platinum alloy surfaces.  

PubMed

A major practical challenge in heterogeneous catalysis is to minimize the loading of expensive platinum group metals (PGMs) without degrading the overall catalytic efficiency. Gaining a thorough atomic-scale understanding of the chemical/structural changes occurring during catalyst manufacture/operation could potentially enable the design and production of "nano-engineered" catalysts, optimized for cost, stability and performance. In the present study, the oxidation behavior of a Pt-31 at% Pd alloy between 673-1073 K is investigated using atom probe tomography (APT). Over this range of temperatures, three markedly different chemical structures are observed near the surface of the alloy. At 673 K, the surface oxide formed is enriched with Pd, the concentration of which rises further following oxidation at 773 K. During oxidation at 873 K, a thick, stable oxide layer is formed on the surface with a stoichiometry of PdO, beneath which a Pd-depleted (Pt-rich) layer exists. Above 873 K, the surface composition switches to enrichment in Pt, with the Pt content increasing further with increasing oxidation temperature. This treatment suggests a route for tuning the surfaces of Pt-Pd nanoparticles to be either Pd-rich or Pt-rich, simply by adjusting the oxidation temperatures in order to form two different types of core-shell structures. In addition, comparison of the oxidation behavior of Pt-Pd with Pt-Rh and Pd-Rh alloys demonstrates markedly different trends under the same conditions for these three binary alloys. PMID:23276526

Li, Tong; Bagot, P A J; Marquis, E A; Edman Tsang, S C; Smith, G D W

2012-11-15

410

Welding of titanium alloy by Disk laser  

NASA Astrophysics Data System (ADS)

The following article describes results of investigations on influence of laser welding parameters on the weld shape, quality and mechanical properties of 2.0 mm thick butt joints of titanium alloy Ti6Al4V (Grade 5 according to ASTM B265) welded with a new generation disk laser TRUMPF TRUDISK 3302, emitting at 1030 nm, with maximum output power 3300 W at circular laser beam spot, characterized by laser beam divergence 8.0 mm•mrad. The test butt joints of Ti6Al4V titanium alloy sheets were prepared as single square groove (I-type joint) and one-side laser welded without an additional material, at a flat position, using a specially designed system for shielding gas (purity 99.999%). The investigations at the initial stage were focused on detailed analysis of influence of the basic laser welding parameters such as laser power and welding speed on the shape and quality of single bead produced during bead-on-plate welding. Then the optimal parameters were chosen for laser welding of 2.0 mm thick butt joints of the titanium alloy Ti6Al4V. Edges of the titanium alloy sheets were melted in argon atmosphere by the laser beam focused on the top surface of butt joints. The test welded joints were investigated by visual inspection, metallographic examinations, hardness and micro-hardness measurements and mechanical tests such as tensile tests and bending tests. It was found that the welding mode is a keyhole welding and providing high quality of joints requires a special techniques and conditions of laser welding, as well as special gas shielding nozzles is required.

Lisiecki, Aleksander

2013-01-01

411

Surface Segregation in Ternary Alloys.  

National Technical Information Service (NTIS)

Surface segregation profiles of binary (Cu-Ni, Au-Ni, Cu-Au) and ternary (Cu-Au-Ni) alloys are determined via Monte Carlo-Metropolis computer simulations using the BFS method for alloys for the calculation of the energetics. The behavior of Cu or Au in Ni...

B. Good G. H. Bozzolo P. B. Abel

2000-01-01

412

Precipitation hardening of aluminum alloys  

Microsoft Academic Search

The author's charge was to discuss recent trends in research and development on precipitation hardened aluminum alloys and to indicate where research is needed. This will be done for three areas: fatigue, properties of grain boundaries and interfaces, and stability of precipitates at elevated temperatures. Present strong precipitation hardened aluminum alloys do not have high endurance limits. One problem is

Morris E. Fine

1975-01-01

413

Multiphase solidification in multicomponent alloys  

Microsoft Academic Search

Multiphase solidification in multicomponent alloys is pertinent to many commercial materials and industrial processes, while also raising challenging questions from a fundamental point of view. Within the past few years, research activities dedicated to multiphase solidification of ternary and multicomponent alloys experienced considerable amplification. This paper gives an overview of our present understanding in this field and the experimental techniques

U. Hecht; L. Gránásy; T. Pusztai; B. Böttger; M. Apela; V. Witusiewicz; L. Ratke; J. De Wilde; L. Froyen; D. Camel; B. Drevet; G. Faivre; S. G. Fries; B. Legendre; S. Rex

2004-01-01

414

Chloride removal from plutonium alloy  

Microsoft Academic Search

SRP is evaluating a program to recover plutonium from a metallic alloy that will contain chloride salt impurities. Removal of chloride to sufficiently low levels to prevent damaging corrosion to canyon equipment is feasible as a head-end step following dissolution. Silver nitrate and mercurous nitrate were each successfully used in laboratory tests to remove chloride from simulated alloy dissolver solution

1983-01-01

415

Fracture Toughness in Titanium Alloys.  

National Technical Information Service (NTIS)

Over the past decade, a concentrated effort has been made by both producers and aerospace users of titanium alloys to develop alloys for future aircraft applications. This effort has been motivated to a large extent by the advent of new design criteria an...

G. R. Keller J. C. Chesnutt F. H. Froes C. G. Rhodes

1978-01-01

416

Derivative spectrophotometry of cobalt alloys  

Microsoft Academic Search

The method of derivative spectrophotometry is briefly described, and derivative absorption spectra are presented for samarium, cobalt, and commercial Sm-Co alloys. It is shown that the use of derivative spectrophotometry not only improves the accuracy and selectivity of element determinations but also simplifies the analysis of alloys. Results of a statistical evaluation of the metrological characteristics of the analytical procedure

Spitsyn

1985-01-01

417

Titanium-tantalum alloy development  

Microsoft Academic Search

Research has been underway at Los Alamos National Laboratory for several years to develop an alloy capable of containing toxic materials in the event of a fire involving a nuclear weapon. Due to their high melting point, good oxidation resistance, and low solubility in molten plutonium, alloys based on the Ti-Ta binary system have been developed for this purpose. The

J. D. Cotton; J. F. Bingert; P. S. Dunn; D. P. Butt; R. W. Margevicius

1996-01-01

418

GTD111 alloy material study  

Microsoft Academic Search

Very few property data on this common turbine blade alloy have been published. As longer hours of service are accumulated, maintenance considerations such as developing optimum component life strategies and repair processes become important. The lack of specific material data hampers the effort of users and repair facilities to achieve optimum service from this alloy. This study measured some of

J. A. Daleo; J. R. Wilson

1998-01-01

419

Mössbauer spectroscopy of zirconium alloys  

NASA Astrophysics Data System (ADS)

Mössbauer investigations of zirconium alloys were examined. Data about the chemical state of iron atoms in the zirconium alloys of different composition has been provided. Mössbauer spectroscopy revealed that small quantities of iron in binary zirconium alloy are in the solid solution ?-Zr (up to 0.02 wt.%). Different iron atoms concentration and thermo-mechanical treatments may lead to formation the intermetallic compounds Zr3Fe, Zr2Fe, ZrFe2. Adding tin atoms does not affect the formation and shape of Mössbauer spectra of these compounds. Adding Cr and Nb atoms makes significant changes in the shape of Mössbauer spectra and leads to the formation of complex intermetallic compounds. Adding Cu and W atoms, the shape of the binary alloys spectra (Zr-Fe) remains unchanged, but a change in the temperature dependence behavior of the spectral parameters occurs and also, changes to the properties of the alloys.

Filippov, V. P.; Bateev, A. B.; Lauer, Yu. A.; Kargin, N. I.

2013-04-01

420

Design of stable nanocrystalline alloys.  

PubMed

Nanostructured metals are generally unstable; their grains grow rapidly even at low temperatures, rendering them difficult to process and often unsuitable for usage. Alloying has been found to improve stability, but only in a few empirically discovered systems. We have developed a theoretical framework with which stable nanostructured alloys can be designed. A nanostructure stability map based on a thermodynamic model is applied to design stable nanostructured tungsten alloys. We identify a candidate alloy, W-Ti, and demonstrate substantially enhanced stability for the high-temperature, long-duration conditions amenable to powder-route production of bulk nanostructured tungsten. This nanostructured alloy adopts a heterogeneous chemical distribution that is anticipated by the present theoretical framework but unexpected on the basis of conventional bulk thermodynamics. PMID:22923577

Chookajorn, Tongjai; Murdoch, Heather A; Schuh, Christopher A

2012-08-24

421

Plate-shaped transformation products in zirconium-base alloys  

SciTech Connect

Plate-shaped products resulting from martensitic, diffusional, and mixed mode transformations in zirconium-base alloys are compared in the present study. These alloys are particularly suitable for the comparison in view of the fact that the lattice correspondence between the parent {beta} (bcc) and the product {alpha} (hcp) or {gamma}-hydride (fct) phases are remarkably similar for different types of transformations. Crystallographic features such as orientation relations, habit planes, and interface structures associated with these transformations have been compared, with a view toward examining whether the transformation mechanisms have characteristic imprints on these experimental observables.

Banerjee, S.; Dey, G.K.; Srivastava, D. [Bhabba Atomic Research Center, Mumbai (India). Materials Science Div.; Ranganathan, S. [Indian Inst. of Science, Bangalore (India)

1997-11-01

422

New magnetic alloys.  

PubMed

Three notable new developments in magnetic alloys are highlighted. These include rare earth-cobalt permanent magnets with maximum energy products up to 240 kilojoules per cubic meter; chromium-cobalt-iron permanent magnets that have magnetic properties similar to those of the Alnicos, but contain only about half as much cobalt and are sufficiently ductile to be cold-formable; and high-induction grain-oriented silicon steels that exhibit 20 percent less core loss as transformer core materials than conventional oriented grades. PMID:17772813

Chin, G Y

1980-05-23

423

Thermomechanical treatment of alloys  

SciTech Connect

An article of an alloy of AISI 316 stainless steel is reduced in size to predetermined dimensions by cold working in repeated steps. Before the last reduction step the article is annealed by heating within a temperature range, specifically between 1010/sup 0/ C. and 1038/sup 0/ C. for a time interval between 90 and 60 seconds depending on the actual temperature. By this treatment the swelling under neutron bombardment by epithermal neutrons is reduced while substantial recrystallization does not occur in actual use for a time interval of at least of the order of 5000 hours.

Bates, J.F.; Brager, R.; Paxton, M.

1983-12-20

424

New magnetic alloys  

NASA Astrophysics Data System (ADS)

Three notable new developments in magnetic alloys are highlighted. These include rare earth-cobalt permanent magnets with maximum energy products up to 240 kilojoules per cubic meter; chromium-cobalt-iron permanent magnets that have magnetic properties similar to those of the Alnicos, but contain only about half as much cobalt and are sufficiently ductile to be cold-formable; and high-induction grain-oriented silicon steels that exhibit 20 percent less core loss as transformer core materials than conventional oriented grades.

Chin, G. Y.

1980-05-01

425

Environmental fatigue in aluminum-lithium alloys  

Microsoft Academic Search

Aluminum-lithium alloys exhibit similar environmental fatigue crack growth characteristics compared to conventional 2000 series alloys and are more resistant to environmental fatigue compared to 7000 series alloys. The superior fatigue crack growth behavior of Al-Li alloys 2090, 2091, 8090, and 8091 is due to crack closure caused by tortuous crack path morphology and crack surface corrosion products. At high R

Robert S. Piascik

1992-01-01

426

CO2 laser welding of magnesium alloys  

Microsoft Academic Search

Metallic alloys with a low mass density can be considered to be basic materials in aeronautic and automotive industry. Magnesium alloys have better properties than aluminum alloys in respect of their low density and high resistance to traction. The main problems of magnesium alloy welding are the inflammability, the crack formation and the appearance of porosity during the solidification. The

Mohammed Dhahri; Jean Eric Masse; J. F. Mathieu; Gerard Barreau; Michel L. Autric

2000-01-01

427

Heat Treatment of New Cast Aluminum Alloys.  

National Technical Information Service (NTIS)

Contents: Brief outline of new thermally hardenable aluminum alloys included in GOST 2685-63; Heat treatment of alloys of the system Al-Mg; Heat treatment of new complex alloys based on the Al-Cu system; Heat treatment of alloys of the Al-Zn-Mg system; Ty...

N. N. Belousov E. N. Mikheeva M. N. Sarafanova

1968-01-01

428

Friction weldability of 7075 aluminium alloy  

Microsoft Academic Search

Friction welding is a solid state joining process and is widely being considered for aluminum alloys. 7075 is an aluminum alloy, with zinc as the primary alloying element. Due to its strength, high density, thermal properties, High strength precipitation hardening, 7075 aluminum alloys are extensively used in aerospace industry. It has good fatigue strength and average mach inability, but has

R. Sathish; D. Ananthapadmanaban; G. S. Nixon; V. Harish

2010-01-01

429

Microstructures and mechanical properties of Ti-Mo alloys cold-rolled and heat treated  

SciTech Connect

In this study, the microstructures and mechanical properties of Ti-10Mo and Ti-20Mo alloys (mass%) are investigated to assess the potential use in biomedical applications. The microstructures are examined by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The mechanical properties are determined from uniaxial tensile tests. The experimental results indicate that the microstructures and mechanical properties of Ti-Mo alloys are dependent upon the cold rolling, solution heat treatment, and Mo content. The Ti-10Mo alloy exhibits ({alpha}'' + {beta}) and ({beta} + {omega}) phases under the cold rolling (CR) and solution treatment (ST), respectively. By contrast, the Ti-20Mo alloy comprises only {beta} phase under such conditions. The quenched Ti-20Mo alloy has the lowest elastic modulus and CR Ti-20Mo alloy has the highest tensile strength. The quenched Ti-10Mo alloy exhibits the excellent ductility and two-stage yielding from stress-strain curves due to the stress-induced martensite transformation from {beta} to {alpha}'' during tensile deformation. These Ti-Mo alloys exhibit low yield strength and good ductility, and they are more suitable for biomedical applications than the conventional metallic biomaterials from the viewpoint of better mechanical compatibility. The quenched Ti-10Mo alloy has some advantages over the other {beta} binary Ti-Mo alloys for biomedical applications. {beta} type Ti-Mo-Sn alloys are expected to be promising candidates for novel metallic biomaterials. - Highlights: {yields} The microstructures and mechanical properties of Ti-Mo alloys are dependent upon the cold rolling, solution heat treatment, and Mo content. {yields} The quenched Ti-10Mo alloy exhibits the excellent ductility and two-stage yielding due to stress-induced martensite transformation from beta to alpha double prime during tensile deformation. {yields} The Ti-Mo alloys are more suitable for biomedical applications than the conventional metallic biomaterials from the viewpoint of better mechanical compatibility. {yields} The quenched Ti-10Mo alloy has more advantages over the other beta binary Ti-Mo alloys for biomedical applications.

Zhou Yinglong, E-mail: yinglongzhou@126.com [Department of Mechatronics Engineering, Foshan University, 18 Jiangwan Yi Rd, Foshan 528000, Guangdong Province (China); Luo Dongmei [Department of Civil Engineering, Foshan University, 18 Jiangwan Yi Rd, Foshan 528000, Guangdong Province (China)

2011-10-15

430

General and localized corrosion of magnesium alloys: A critical review  

NASA Astrophysics Data System (ADS)

Magnesium (Mg) alloys as well as experimental alloys are emerging as light structural materials for current, new, and innovative applications. This paper describes the influence of the alloying elements and the different casting processes on the microstructure and performance of these alloys and corrosion. It gives a comprehensible approach for the resistance of these alloys to general, localized and metallurgically influenced corrosion, which are the main challenges for their use. Exposure to humid air with ˜65% relative humidity during 4 days gives 100-150 nm thickness. The film is amorphous and has an oxidation rate less than 0.01 µm/y. The pH values between 8.5 and 11.5 correspond to a relatively protective oxide or hydroxide film; however above 11.5 a passive stable layer is observed. The poor corrosion resistance of many Mg alloys can be due to the internal galvanic corrosion caused by second phases or impurities. Agitation or any other means of destroying or preventing the formation of a protective film leads to increasing corrosion kinetics. The pH changes during pitting corrosion can come from two different reduction reactions: reduction of dissolved oxygen (O) and that of hydrogen (H) ions. Filiform corrosion was observed in the uncoated AZ31, while general corrosion mainly occurred in some deposition coated alloys. Crevice corrosion can probably be initiated due to the hydrolysis reaction. Exfoliation can be considered as a type of intergranular attack, and this is observed in unalloyed Mg above a critical chloride concentration.

Ghali, Edward; Dietzel, Wolfgang; Kainer, Karl-Ulrich

2004-02-01

431

Atmospheric Corrosion of Different Fe-based Alloys in Nanocrystalline State  

NASA Astrophysics Data System (ADS)

Nanocrystalline Fe-based alloys are interesting for their soft magnetic properties. Because these alloys are potentially applicable in outdoor-working components, their corrosion behaviour requires careful analysis. This work presents the results of the atmospheric corrosion tests in industrial and rural environments performed for up to 6 months. We compared the corrosion behaviour of two different compositions of NANOPERM-type alloys: Fe87.5Zr6.5B6 and Fe76Mo8Cu1B15 with classical FINEMET alloys of the nominal composition of Fe73.5Cu1Nb3Si13.5B9 type. The techniques of Mössbauer spectroscopy, conversion electron Mössbauer spectroscopy, X-ray diffraction and transmission electron microscopy have been employed to compare their corrosion rate, characterize corrosion products and inspect the structural changes of the nanocrystalline structure. It was found that the Si-containing FINEMET alloys are the most corrosion-resistant whereas worse corrosion properties were observed for molybdenum-containing Fe76Mo8Cu1B15 alloy. The corrosion product formed on the surface of NANOPERM-type alloys showed a needlelike morphology and a poor crystalline order and has been identified as lepidocrocite, ?-FeOOH.

Sitek, J.; Sedla?ková, K.; Seberíni, M.

2005-07-01

432

The role of grain boundary character in the environmentally-assisted intergranular cracking mechanism of nickel-base alloys: Progress report, August 1, 1987-July 31, 1988  

SciTech Connect

Grain boundary chemistry and structure of high-purity Inconel 690- type alloys (carbon doped) were studied. Heat treatments were carried out to assess the modified (for alloy 690) DEPLETE code. Chromium, depletion profiles were measured. Grain boundary orientation will be measured using electron channeling. Constant elongation note tests were conducted to evaluate the dependence of IGSCC susceptibility on grain boundary chemistry. Effects of hydrogen on grain boundary fracture was studied as a function of grain boundary structure, temperature and alloy composition (Ni, alloy 600, alloy 690). 16 refs., 6 figs., 9 tabs. (DLC)

Was, G.S.

1988-07-01

433

Physicochemical laws of the interaction of nickel aluminides with alloying elements: II. Interaction of nickel aluminides with alloying elements and\\/or interstitial phases  

Microsoft Academic Search

The Ni-Al-X (X is an interstitial element or phase) phase diagrams are analyzed to reveal systems that can be used as the basis for designing\\u000a promising alloys and natural composites based on nickel aluminides reinforced by interstitial phases (natural composites I).\\u000a The most thermally stable materials are shown to be heterophase alloys and composite materials (CMs) located in the eutectic-type

K. B. Povarova; N. K. Kazanskaya; A. A. Drozdov; A. E. Morozov

2007-01-01

434

Microstructural characterization of as-cast biocompatible Co-Cr-Mo alloys  

SciTech Connect

The microstructure of a cobalt-base alloy (Co-Cr-Mo) obtained by the investment casting process was studied. This alloy complies with the ASTM F75 standard and is widely used in the manufacturing of orthopedic implants because of its high strength, good corrosion resistance and excellent biocompatibility properties. This work focuses on the resulting microstructures arising from samples poured under industrial environment conditions, of three different Co-Cr-Mo alloys. For this purpose, we used: 1) an alloy built up from commercial purity constituents, 2) a remelted alloy and 3) a certified alloy for comparison. The characterization of the samples was achieved by using optical microscopy (OM) with a colorant etchant to identify the present phases and scanning electron microscopy (SE-SEM) and energy dispersion spectrometry (EDS) techniques for a better identification. In general the as-cast microstructure is a Co-fcc dendritic matrix with the presence of a secondary phase, such as the M{sub 23}C{sub 6} carbides precipitated at grain boundaries and interdendritic zones. These precipitates are the main strengthening mechanism in this type of alloys. Other minority phases were also reported and their presence could be linked to the cooling rate and the manufacturing process variables and environment. - Research Highlights: {yields}The solidification microstructure of an ASTM-F75 type alloy were studied. {yields}The alloys were poured under an industrial environment. {yields}Carbides and sigma phase identified by color metallography and scanning microscopy (SEM and EDS). {yields}Two carbide morphologies were detected 'blocky type' and 'pearlite type'. {yields}Minority phases were also detected.

Giacchi, J.V., E-mail: jgiacchi@exa.unicen.edu.ar [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Instituto de Fisica de Materiales Tandil (IFIMAT-FCE-CICPBA) Facultad de Ciencias Exactas, Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399 B7000GHG Tandil (Argentina); Morando, C.N.; Fornaro, O. [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Instituto de Fisica de Materiales Tandil (IFIMAT-FCE-CICPBA) Facultad de Ciencias Exactas, Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399 B7000GHG Tandil (Argentina); Palacio, H.A. [Comision de Investigaciones Cientificas de la Provincia de Buenos Aires (CICPBA), Calle 526 e/10 y 11 B1096APP La Plata (Argentina); Instituto de Fisica de Materiales Tandil (IFIMAT-FCE-CICPBA) Facultad de Ciencias Exactas, Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399 B7000GHG Tandil (Argentina)

2011-01-15

435

Using solidification parameters to predict porosity distributions in alloy castings  

SciTech Connect

Quality criteria used in the computer-aided design and analysis of casting processes typically relate geometric, thermal, or solidification parameters to structural features such as centerline shrinkage and microporosity. Quality criteria for the prediction of porosity in castings have been used successfully in steel, but the application of criteria functions to nonferrous alloys has been less successful. This paper reports that recent work suggests that the dominating mechanism that determines the amount and distribution of porosity in castings is strongly dependent on the solidification mode of the alloy and the solidification conditions. Accordingly, casting processes and alloy types are divided into four groups and a different set of criteria functions are obtained for each group.

Viswanathan, S.; Sikka, V.K. (Oak Ridge National Lab., Oak Ridge, TN (United States)); Brody, H.D. (Univ. of Connecticut, CT (United States))

1992-09-01

436

Heat treatment in high Cr white cast iron Nb alloy  

NASA Astrophysics Data System (ADS)

Wear resistance of high Cr white cast irons can be improved by means of heat treatment. This type of cast iron alloy may present a microstructure with retained austenite. The amount of retained austenite changes with the applied heat treatment, which will have an influence on wear properties. The purpose of this work was to study the influence of several parameters such as quenching and tempering temperatures and subzero treatment in the wear performance of the high Cr white cast iron Nb alloy. In this way, the performance was evaluated using pin-on-disc abrasion test. The worn surface was examined by scanning electron microscopy, and the main wear mechanisms were identified. The microstructural characterization was also performed with carbide identification. This Fe alloy has proven to be good for applications in mining and alcohol-sugar industries.

Farah, A. F.; Crnkovic, O. R.; Canale, L. C. F.

2001-02-01

437

Exchange bias in thin Heusler alloy films in contact with antiferromagnet  

NASA Astrophysics Data System (ADS)

Exchange bias is studied in thin film systems, in which three types of Heusler alloys (Ni2MnSn, Co2MnSn, and Co2FeSi) are in contact with an antiferromagnet. Magnetic exchange interactions between the constituting atoms (i.e., Ni-Mn, Mn-Mn, Co-Mn, and Co-Fe, or Co-Co) differ substantially in these Heusler alloys. We explain the influence of the exchange stiffness A within the Heusler alloys and of the exchange coupling between Heusler alloy and an antiferromagnet in a finite interface volume. Insertion of an ultrathin Co layer at interfaces brings about an enhancement of the exchange bias in Heusler alloy/antiferromagnet layer system.

Dubowik, J.; Go?cia?ska, I.; Za??ski, K.; G?owi?ski, H.; Kudryavtsev, Y.; Ehresmann, A.

2013-05-01

438

Principles of the alloying of steel in a beam of relativistic electrons  

NASA Astrophysics Data System (ADS)

It is shown that it is possible to significantly strengthen steel by alloying a surface layer melted by the energy from a beam of relativistic electrons. A study was made of the effect of different treatment parameters (accelerating voltage, beam current, specimen velocity and temperature, etc.) on the structure, depth, hardness, and wear resistance of the alloyed layer. Several types of alloying mixtures were developed based on carbides of tungsten, chromium, and boron, and including special additions and modifiers. The proportions of the components was optimized. The technology of alloying in a beam of relativistic electrons is compared with vacuum electron-beam alloying. Heat treatment is used to additionally improve the structure of the layers.

Poletika, I. M.; Borisov, M. D.; Kraev, G. V.; Vaisman, A. F.; Golkovskii, M. G.; Durakov, V. A.

1996-03-01

439

Inhibition of Corrosion of 3003 Aluminum Alloy in Ethylene Glycol-Water Solutions  

NASA Astrophysics Data System (ADS)

In this study, the inhibiting effects of four types of inhibitors, including gluconate, cinnamate, molybdate, and nitrate, on corrosion of a 3003 aluminum (Al) alloy were investigated in ethylene glycol-water solutions that simulate the automotive coolant by various electrochemical measurements. It was found that the tested inhibitors were effective to inhibit corrosion of 3003 Al alloy under both static and turbulent flow conditions. They all behave as anodic inhibitors, which inhibit the Al alloy corrosion by passivating Al alloy and decreasing its anodic current density. A turbulent flow of the solution decreases the corrosion resistance of Al alloy and the inhibiting effect of the inhibitors. The inhibiting effect of the inhibitors is ranked as: nitrate > cinnamate > gluconate > molybdate.

Liu, Y.; Cheng, Y. F.

2011-03-01

440

Industrial Experience on the Caustic Cracking of Stainless Steels and Nickel Alloys - A Review  

SciTech Connect

Caustic environments are present in several industries, from nuclear power generation to the fabrication of alkalis and alumina. The most common material of construction is carbon steel but its application is limited to a maximum temperature of approximately 80 C. The use of Nickel (Ni) alloys is recommended at higher temperatures. Commercially pure Ni is the most resistant material for caustic applications both from the general corrosion and the stress corrosion cracking (SCC) perspectives. Nickel rich alloys also offer a good performance. The most important alloying elements are Ni and chromium (Cr). Molybdenum (Mo) is not a beneficial alloying element and it dissolves preferentially from the alloy in presence of caustic environments. Austenitic stainless steels such as type 304 and 316 seem less resistant to caustic conditions than even plain carbon steel. Experimental evidence shows that the most likely mechanism for SCC is anodic dissolution.

Rebak, R B

2005-10-09

441

Microstructure Evolution and Mechanical Properties of As-Cast Pb-Mg-Al Alloys  

NASA Astrophysics Data System (ADS)

In this study, two new types of Pb-Mg-Al alloys with high tensile strength and hardness were prepared by casting under the molten salt. The microstructure and morphology of the Pb-Mg-Al alloys were investigated through x-ray diffraction and scanning electron microscope analysis. Mechanical properties of the alloys were compared with those of the pure Pb and its alloys, and the results indicate that the tensile strength and hardness increase, respectively, up to 300 MPa and 156 HB with the 10 wt.% addition of Al. The fractographic examinations indicate that the fracture model of Pb-Mg-Al alloys changes from mixed intergranular-transgranular to the intergranular quasi-cleavage with the increase in Al content.

Duan, Y. H.; Sun, Y.; Peng, M. J.; Guo, Zh. Zh.; Zhu, P. X.

2012-06-01

442

Effect of surface doping on the oxidation of chromia former alloys  

NASA Astrophysics Data System (ADS)

Y, Ce, La, Hf, Ca, and Zr were applied to the surfaces of type 304 and 310 stainless steels and In 738, a nickel base alloy. In order to determine the effect of the minor alloying elements in stainless steels on the surface doping effect, Y was applied to three alloy modifications of type 304SS. The presence or absence of Mn and Si in the alloy on the high temperature corrosion behavior was determined. Several different doping techniques were used to determine which technique was most beneficial to the behavior of the oxide barrier scale. The application of Y, Ce and La was found to enhance the oxidation resistance of the commercial stainless steels while no benefits were found for alloys doped with Hf, Ca and Zr. It was determined that Si had to be present in the type 304 SS for the doping process to enhance the oxidation resistance. There was no beneficial effect on modified 304SS containing Mn only or without Mn or Si. The yttrium doped and undoped modified type 304SS with Si only showed more resistance to scale spallation than any other type 304SS alloy tested, either commercial or modified.

Landkof, M.; Boone, D. H.; Gray, R.; Levy, A. V.; Yaniv, E.

1984-04-01

443

Effect of surface doping on the oxidation of chromia former alloys  

SciTech Connect

Y, Ce, La, Hf, Ca, and Zr were applied to the surfaces of type 304 and 310 stainless steels and IN 738, a nickel base alloy. In order to determine the effect of the minor alloying elements in stainless steels on the surface doping effect, Y was applied to three alloy modifications of type 304SS. The presence or absence of Mn and Si in the alloy on the high temperature corrosion behavior was determined. Several different doping techniques were used to determine which technique was most beneficial to the behavior of the oxide barrier scale. The application of Y, Ce and La was found to enhance the oxidation resistance of the commercial stainless steels while no benefits were found for alloys doped with Hf, Ca and Zr. It was determined that Si had to be present in the type 304 SS for the doping process to enhance the oxidation resistance. There was no beneficial effect on modified 304SS containing Mn only or without Mn or Si. The yttrium doped and undoped modified type 304SS with Si only showed more resistance to scale spallation than any other type 304SS alloy tested, either commercial or modified. 21 figures, 11 tables.

Landkof, M.; Boone, D.H.; Gray, R.; Levy, A.V.; Yaniv, E.

1984-04-01

444

The site occupancies of alloying elements in TiAl and Ti{sub 3}Al alloys  

SciTech Connect

The site occupancies of V, Cr, Mn, Fe, Ni, Zr, Nb, Mo, Ta, Ga and Sn (1--5 at.%) in TiAl alloys with different compositions, and in Ti{sub 3}Al with the compositions of Ti-26 at.%Al-(1--2 at.%)X, were measured by the atom location channeling enhanced microanalysis (ALCHEMI) method. For TiAl alloys, the results show that Zr, Nb and Ta atoms invariably occupy Ti sites, while Fe, Ni, Ga and Sn atoms occupy Al sites, the alloy composition having no significant influence on their site preference. By contrast, the site preference of V, Cr, and Mn changes considerably with alloy composition (the Ti/Al ratio in particular), the probability of these elements substituting for Ti decreasing in the above order. For quaternary Ti-Al-V-Cr alloys, the site occupancies of V and Cr do not show much mutual influence. In general, with increasing atomic number, elements in the same period show increasing tendency to substitute for Al, as is the tendency to substitute for Ti for elements in the same group of the periodic table. For Ti{sub 3}Al alloys, Ga and Sn atoms occupy Al sites, while V, Cr, Mn, Zr, Nb, Mo and Ta atoms occupy Ti sites, the site preference of V, Cr, Mn and Mo in TiAl alloys being different from that in Ti{sub 3}Al. The experimental results are interpreted in terms of a Bragg-Williams-type model and bond-order data obtained from electronic structure calculation. Qualitative agreement between the model and measurements is reached.

Hao, Y.L.; Xu, D.S.; Cui, Y.Y.; Yang, R.; Li, D. [Chinese Academy of Sciences, Shenyang (China). Inst. of Metal Research

1999-03-10

445

Shear bands in aluminum-lithium alloys  

Microsoft Academic Search

Lithium-alloyed aluminum alloys possess substantial advantages over other aluminum-base alloys and can be a promising material\\u000a for spacecraft engineering in the next century. At the present time the use of these alloys is limited by certain manufacturing\\u000a difficulties. For example, the shear bands that appear in rolling of Al?Li sheets exert a negative effect on the properties\\u000a of the alloys.

T. D. Rostova; V. V. Zakharov

1997-01-01

446

Simulation of an Amorphous Metalic Alloy: Ag-Cu  

NASA Astrophysics Data System (ADS)

The development of new metallic alloys which form bulk glasses at low cooling rates has led to significant advances in the study of undercooled liquid metals and the glass transition in metallic systems. These new materials exhibit a rich variety of phenomena, such as liquid-crystal phase separation and nanocrystalline phase formation, and have interesting potential as engineering materials. We have re-parametrized empirical analytical many body potentials of Sutton-Chen type for FCC metals in order to study the thermophysical properties of these metals and their alloys. The properties we studied are viscosity, diffusion, melting, and glass formation. In this talk, we will present molecular dynamics studies on Ag, Cu, and Ag-Cu binary alloy. Ag-Cu alloy is a perfect model system for a glass former, since the elements Ag and Cu have considerably different atomic radii. Using molecular dynamics method under constant pressure, constant temperature we studied the melting and glass tranformation for this alloy at the eutectic composition. We report glass transition temperature as a function of cooling rate; structural and thermodynamic properties of the model Ag-Cu glass.

Qi, Yue; Cagin, Tahir; Goddard, William A., III

1998-03-01

447

AES study of passive films formed on a type 316 austenitic stainless-steels in a stress field  

Microsoft Academic Search

The type AISI 316 stainless steel, in addition to the principal alloying elements chromium and nickel, contains 2.5–3.5% of molybdenum. This element is added to improve the mechanical properties and the pitting resistance of austenitic alloys. Concerning the Stress Corrosion Cracking (SCC) resistance of austenitic stainless steels, molybdenum additions to alloys have a variable effect: the effect is detrimental for

F. Navaï; O. Debbouz

1999-01-01

448

A short-term clinical follow-up study of superplastic titanium alloy for major connectors of removable partial dentures  

Microsoft Academic Search

Statement of problem . Superplastic forming of Ti-6Al-4V alloy has been used in the fabrication of a removable denture framework. The method provides the titanium alloy denture framework with excellent physical properties not seen in cast titanium prostheses.Purpose . This study describes the technical procedure for fabricating removable dentures with this type of framework and evaluates clinical applications of the

Noriyuki Wakabayashi; Minoru Ai

1997-01-01

449

A study of damage under tensile loading in a new Al-Si-Fe alloy processed by the Osprey route  

Microsoft Academic Search

The mode of damage in tension of a new Al-Si-Fe alloy made by spray deposition was studied. This alloy has a composite type structure composed of silicon and intermetallic particles in an aluminium matrix. In situ tensile tests in the SEM, with gold microgrids deposited on the surface of the specimen as an indicator of local plastic strains, provide us

A. Mocellin; R. Fougeres; P. F. Gobin

1993-01-01

450

A neutron diffraction and magnetization study of Heusler alloys containing Co and Zr, Hf, V or Nb  

Microsoft Academic Search

Neutron diffraction, x-ray diffraction, and saturation magnetization ; measurements have been made on a series of ferromagnetic alloys at the ; composition CoâYZ, where Y is a group IVA or VA element and Z is a group ; IIIB or IVB element. The alloys are mainly ordered in the Heusler L2⁠type ; chemical structure, but some show the presence

K. R. A. Ziebeck; P. J. Webster

1974-01-01

451

Silicon Solar Cells with Front Hetero-Contact and Aluminum Alloy Back Junction: Preprint  

SciTech Connect

We prototype an alternative n-type monocrystalline silicon (c-Si) solar cell structure that utilizes an n/i-type hydrogenated amorphous silicon (a-Si:H) front hetero-contact and a back p-n junction formed by alloying aluminum (Al) with the n-type Si wafer.

Yuan, H.-C.; Page, M. R.; Iwaniczko, E.; Xu, Y.; Roybal, L.; Wang, Q.; Branz, H. M.; Meier, D. L.

2008-05-01

452

Development of lead-free copper alloy graphite castings. Annual report, January--December 1995  

SciTech Connect

The distribution of graphite particles in graphite containing copper alloy was further improved very significantly using several procedures and technological modifications. The developed techniques attacked the graphite distribution problem in two ways. Realizing that clustering of very fine (5um) graphite particles is one of the two major problems, a pretreatment process has been developed using aluminum powders to deagglomerate graphite particles. Along with this, a two-stage stirring technique was used to first incorporate and then to distribute uniformly the deagglomerated particles in the melt. During this year, based on these developments, several components were cast to evaluate the castability of Cu alloy-graphite melts. In addition, machinability tests were done to clearly established that addition of graphite particles improve the machinability of copper MMC alloys over and above that of monolithic copper alloys. The results show that the machining chip sizes and cutting forces of Cu alloys containing graphite particles are smaller than these of the corresponding monolithic Cu alloys. This clearly establishes that the presence of graphite particles in copper alloy improves the machinability in a fashion similar to lead additions to copper alloys. Centrifugal casting of shapes of different sizes appear to be a very attractive method for casting graphite containing copper alloys, since all the graphite particles (regardless of their distribution in the melt) are forced to segregate to the inner periphery of the castings where they impart a very desirable solid lubrication property for bushing and bearing use. A very large number of cylindrical elements of lead bearing copper alloys are now used for similar bearing bushing applications and the manufacturers of these type of bearings are under safety and health hazard pressure to remove lead. This year several parameters for centrifugal casting of copper graphite alloys have been established.

Rohatgi, P.K.

1996-10-01

453

Structure and magnetic properties of nanostructured MnNi alloys fabricated by mechanical alloying and annealing treatments  

NASA Astrophysics Data System (ADS)

A nearly equiatomic MnNi alloy was fabricated from the elemental powders by means of mechanical alloying in a planetary ball milling apparatus. X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and measurements of magnetization were conducted to identify the structural states and properties of the prepared alloys. After ball milling for 20 h, a disordered face-centered cubic (f.c.c.) solid solution was formed which increased in lattice parameter by further milling up to 50 h. An exothermic reaction took place at around 300-400°C during continuous heating of the disordered f.c.c. solid solution. This reaction is attributed to a structural ordering leading to the formation of a face-centered tetragonal (f.c.t.) phase with L10 type ordering. Examination of the magnetic properties indicated that the structural ordering increases remnant magnetization and decreases coerecivity.

Jalal, T.; Hossein Nedjad, S.; Khalili Molan, S.

2013-05-01

454

Some thoughts on alloy design  

SciTech Connect

This paper discusses some of the problems associated with attempts to use first principles in alloy design. We briefly summarize the role of microstructure on the properties of high temperature alloys and illustrate some of the microstructural features of conventional superalloys. We also describe how theory and experiment are converging toward some predictive capabilities for relating microstructure and composition using Ni-Al-Mo-X alloys as an example. Finally, this paper suggests that progress is being made in combining the results of condensed matter theory and experimental research.

Martin, P.L.; Williams, J.C.

1984-01-01

455

Hot-Dip Galvanizing Alloys  

NASA Astrophysics Data System (ADS)

Activity in the development of hotdip galvanizing alloys has been quite successful in achieving two major goals. First, the use of a zinc-nickel bath provides a workable solution to the problem of batch galvanizing reactive steels, to achieve both an attractive surface appearance and a thin, durable and protective coating. Second, for continuously galvanized steel products, specific zinc-aluminum alloys have provided a means to greatly increase corrosion resistance, increase the maximum use temperature of zinc coatings, achieve the fabrication of severely formed products without damage to the zinc alloy coating, and allow such products to be formed from prepainted as well as unpointed coated steel.

Lynch, Richard F.

1987-08-01

456

A new approach to refining and modifying cast aluminum alloys with rare earth alloys  

Microsoft Academic Search

The effects of rare earth (RE) alloys on the refining and modifying of cast aluminum alloys were investigated. Compared to\\u000a other substances in common use, rare earth alloys maintain the refining and modifying effects of the aluminum alloys for a\\u000a longer time. RE alloys can also reduce environmental pollution in the melting process. These effects of RE alloys make them

Duo-guang Tang; Xie-min Mao

2000-01-01

457

Characteristics of ceramic particle reinforced Al composite powder manufactured by a stone mill type crusher using twin roll cast Al alloy flake: a model on the formation of composite powder  

Microsoft Academic Search

5083 and 6061 aluminium composite powders have been manufactured by a newly designed stone mill type crusher using twin rolled 5083 and 6061 flakes and ceramic powders such as Al2O3-TiC and Al2O3-B4C synthesized by self-propagating high-temperature synthesis (SHS) process. This research reports on the effect of such processing parameters as a gap clearance between the disks and the number of

J. H. Lee; T. S. Kim; D. Y. Maeng; H. T. Son; S. J. Hong; C. W. Won; S. S. Cho; B. S. Chun

2001-01-01

458

Relationship between composition, structure, properties, thermo mechanical processing, and ballistic performance of tungsten heavy alloys. Final report, Mar 86-Jul 91  

SciTech Connect

Traditional tungsten heavy alloys are tungsten--nickel--iron or tungsten--nickel--copper alloys containing 88 to 98% tungsten. Cobalt is also used in these alloys but to a lesser extent. These alloys are produced by blending the elemental powders, pressing billets from the blend and then liquid-phase sintering the billets. These alloys were first developed to provide high density materials that were easy to machine but were developed with little concern for mechanical properties. Initially W-Ni-Cu alloys were most common because the low melting point of copper made these alloys easier to sinter. As the demand for alloys with good mechanical properties increased, a shift occurred from the W-Ni-Cu alloys to the W-Ni-Fe alloys. Processing techniques to consistently produce high quality tungsten heavy alloys were developed. The purpose of this program was to do a thorough study of tungsten heavy alloys and the interrelationship between chemical composition, impurities, thermo-mechanical processing history, structure and ballistic properties. Ballistic testing was to include a wide range of types and sizes ranging from an in house 20mm range to full scale testing.

Spencer, J.R.; Mullendore, J.A.

1991-11-01

459

Effect of chromium content on structure and mechanical properties of Ti-7.5Mo-xCr alloys.  

PubMed

The present work is a study of a series of Ti-7.5Mo-xCr alloys with the focus on the effect of chromium content on the structure and mechanical properties of the alloys. Experimental results show that low hardness, strength and modulus binary Ti-7.5Mo alloy is comprised primarily of fine, acicular martensitic alpha' phase. When 1 wt % Cr is added, a small amount of beta phase is retained. With 2 wt % or more chromium added, the entire alloy becomes equi-axed beta phase with bcc crystal structure. The average beta grain size decreases with Cr content. When the alloy contains about 2-4 wt % Cr, a metastable omega phase is present. In Ti-7.5Mo-2Cr alloy appears the highest omega intensity accompanied with high microhardness, bending strength and modulus. The omega-induced embrittling effect is most profound in Ti-7.5Mo-2Cr alloy that exhibits a terrace type fracture surface covered with numerous micron-sized dimples. The alloys with higher Cr contents show normal ductile type fractography with much larger deformation dimples. The present results indicate that Ti-7.5Mo-(4-6)Cr alloys seem to be potential candidates for implant application. PMID:15348532

Lin, D J; Chern Lin, J H; Ju, C P

2003-01-01

460

Local density of unoccupied states in ion-beam-mixed Pd-Ag alloys  

SciTech Connect

X-ray absorption spectroscopy (XAS) measurements have been used to probe the electronic structure of ion-beam-mixed (IBM) Pd-Ag thin films with bulk alloys being studied for comparison. Pd {ital L}{sub 3} and Ag {ital L}{sub 3} absorption edges for pure Pd, Ag, and Pd{sub 1{minus}{ital x}}Ag{sub {ital x}} alloys are discussed. Structural information from both x-ray diffraction and the XAS fine structure oscillations are discussed. The observed decrease of the white-line feature strength, at the Pd {ital L}{sub 3} edge, indicates that the local density of unoccupied Pd 4{ital d} states declines upon alloying with Ag in a manner similar to that observed in previous bulk studies. However, while the Pd {ital d}-hole count decreases monotonically for bulk alloys, in the IBM alloys it saturates at higher levels in the Ag-rich materials. This disparity is interpreted on the basis of a modified charge transfer due to structural differences in the IBM alloys. The Ag {ital L}{sub 3} near-edge region is largely unchanged in these alloys, indicating that the charge transferred away from the Ag site is dominantly of {ital non}-{ital d} type. Our experimental results are discussed in the context of recent electronic structure calculations and of previous work on this alloy system. {copyright} {ital 1996 The American Physical Society.}

Chae, K.H.; Jung, S.M.; Lee, Y.S.; Whang, C.N. [Department of Physics, Yonsei University, Seoul 120-749 (Korea); Jeon, Y. [Department of Physics, Jeonju University, Jeonju 560-759 (Korea); Croft, M.; Sills, D. [Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08855-0849 (United States); Ansari, P.H.; Mack, K. [Department of Physics, Seton Hall University, South Orange, New Jersey 07079 (United States)

1996-04-01

461

Synthesis of Nanocrystalline and Amorphous Alloys from Elementary Powders by Intensive Plastic Deformation Under High Pressure  

NASA Astrophysics Data System (ADS)

Transmission electron microscopy is used to study the structure and phase composition of binary zirconium alloys with Group I-VIII metals produced from metal powders via severe plastic torsional deformation under pressure. The metal contents in the initial mixture, the type of reacting metals, and the degree of deformation are found to affect substantially the structure and phase composition of the alloys synthesized. It is found that the tendency of binary zirconium-based alloys to form an amorphous state depends on the position of an alloying metal in the periodic table. An amorphous state is formed in alloys with Group II (Zn), III (Al), VIII (Co, Ni), and I (Cu) metals; it is not formed in alloys with Group IV (Ti), V (V, Nb), and VI (Mo) metals of the periodic table. Compositions that are close to equiatomic alloys are more favorable for the formation of an amorphous state or the smallest nanograins. In the course of mechanical alloying, high-pressure phases and intermetallic compounds are found to form.

Dobromyslov, A. V.; Churbaev, R. V.

462

The effects of corrosion products from copper dental alloys on lymphocyte proliferation  

SciTech Connect

Copper dental alloys currently being used for dental applications possess mechanical properties similar to the traditional gold alloys. However, it is reported that these alloys have high corrosion rates, cause decreases in gingival fibroblast proliferation and release significant levels of Cu which have been associated with oral inflammatory responses in dogs. The authors investigated the effects of the commercial copper alloys, Goldent and Trindium, on human blood mononuclear cell proliferation. Fresh, human peripheral blood mononuclear cells, the CEM and HSB T-cell lines and the Raji B-cell line were exposed to the copper alloys for 24 hours. While the authors observed decreases in the proliferation of human blood mononuclear cells, as measured by {sup 3}H-thymidine uptake, these decreases were highly variable. The copper dental alloys caused 41-47% reductions in the proliferation of the CEM T-cell line while reducing proliferation in the Raji B-cell line and the HSB T-cell line by 20% or less. In conclusion, the effect of copper dental alloys is highly variable depending upon the cell type. These results indicate that further studies are warranted to adequately determine the biocompatibility of these alloys.

Bumgardner, J.D.; Lucas, L.C.; Tilden, A.B. (Veterans Administration, Birmingham, AL (United States))

1990-02-26

463

Synthesis of nanocrystalline copper–tungsten alloys by mechanical alloying  

Microsoft Academic Search

Copper–tungsten exhibits total absence of solubility in both solid and liquid state. Mechanical alloying (MA) as a solid state, non-equilibrium process can be beneficial to the processing of such an immiscible system with the added features of refinement of structure. A study was undertaken to synthesise various Cu–W alloys and develop an ultrafine microcomposite structure of tungsten in copper matrix

T. Raghu; R. Sundaresan; P. Ramakrishnan; T. R. Rama Mohan

2001-01-01

464

Current status of ductile tungsten alloy development by mechanical alloying  

Microsoft Academic Search

There were considerable differences in ductility and recrystallization temperatures among fine-grained, carbide-dispersed tungsten alloys developed so far by mechanical alloying, followed by sintering and hot working. The differences are attributable mainly to three microstructural factors giving detrimental effects on the ductility and recrystallization temperature; (1) precipitation of the brittle W2C phase, (2) heterogeneity in grain size and particle distributions and

Y. Ishijima; H. Kurishita; K. Yubuta; H. Arakawa; M. Hasegawa; Y. Hiraoka; T. Takida; K. Takebe

2004-01-01

465

New package cooling technology using low melting point alloys  

NASA Astrophysics Data System (ADS)

A novel package cooling technology concept using two kinds of inexpensive low-melting-point alloys is presented. One alloy is Bi-18.0Pb-11.6Sn-21.0In (in wt pct), with a melting point of 57 C; the other is Bi-17.3Sn-25.2In, with a melting point of 77 C. This type of package cooling techology may be extremely useful for high-power circuit packages which are only required to operate for a period of several minutes, such as in certain types of defense electronic equipment applications, and for circuit packages required to operate for several minutes at a time with intervals, such as some types of motor-drive circuits for robotic applications. Diagrams of experimental samples are presented.

Fukuoka, Yoshitake; Ishizuka, Masaru

1990-07-01

466

Shape memory alloy cables  

NASA Astrophysics Data System (ADS)

Conventional structural cables (or wire ropes) are composed of steel wires helically wound into strands, which, in turn, are wound around a core. Cables made from shape memory