The systems-based design of high-strength, high-conductivity alloys

A systems approach to the design of materials involves modeling the interactions of the processing-structure-property links. This approach leads to total optimization of properties both within and beyond the limits of any empirical approach. The design of precipitation-strengthened, high-strength, high-electrical-conductivity alloys provides a unique opportunity for demonstrating the efficiency of this approach. Using this computer-aided design, a new class of alloys with improved strength-conductivity combinations can be designed.     

Some properties of binary vanadium alloys

Conclusions Increasing the concentration of the alloying element in binary alloys of vanadium with titanium, chromium, tin, and aluminum at concentrations of 0–25 wt. % leads to an increase of hardness and electrical resistivity, particularly for alloys with tin and aluminum. The strength will be highest for alloys of vanadium with tin.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 62–63, July, 1971.     

Designing low-thermal-expansivity, high-conductivity alloys in the Cu-Fe-Ni ternary system

Alloys that combine the high electrical and thermal conductivity of copper with the low thermal expansivity and higher strength of Invar (Fe-36Ni), are of interest for a range of applications. In suitable Cu-Fe-Ni alloys, nearly pure copper equilibriates with an Invar-rich solid solution; casting such alloys invariably produces Invar-rich dendrites in a copper-rich solid solution. Two-phase alloys that combine the properties of copper and Invar can be produced by casting followed by suitable heat treatments. The overall composition controls the relative fractions of Invar and copper and the resulting trade-off between low thermal expansivity and high electrical conductivity. Analyses of phase equilibria and load transfer between ductile copper and Invar indicate that effective composites are only feasible for compositions between approximately 20 and 80 percent Invar. R.K. Jain will earn his B.S. in mechanical science at the University of Texas at Austin August. For more information, contact R.D. Cottle, Center for Materials Science and Engineering, University of Texas at Austin, ETC 9.104, Austin, Texas 78712; cottle@mail.utexas.edu.     

MoSi_2增强铜基复合材料的组织与性能

用热压烧结的方法制备了一种以金属间化合物MoSi_2作为增强相的Cu基复合材料,并对其组织、力学性能和导电性能进行了研究.结果表明,MoSi_2是一种合适的铜基复合材料的增强相,MoSi_2/Cu复合材料具有良好的稳定性;MoSi_2具有明显的细化晶粒强化基体的作用;随MoSi_2含量的增加,MoSi_2/Cu复合材料的密度和电导率下降,硬度和抗拉强度表现为先增加后降低;加入2%MoSi_2时,复合材料具有最佳的综合性能,其相对密度和电导率分别为97.44%和68%IACS,硬度和抗拉强度分别为142HV和355MPa,是相同制备条件下纯铜硬度和抗拉强度的2倍多.     

Structural transformations and strain effects in copper and copper-base alloys due to dynamic loading

The strain behavior and phase transformations in Cu-37 wt.% Zn brass, Cu-12.5 wt.% Al bronze, and copper (99.97%) are studied under two variants of pulse loading, i.e., converging shock waves and a flux of powder particles accelerated by explosion. The effects connected with uniform and localized strain caused by the action of shock waves are determined and the disperse structures formed in the materials under dynamic loading are analyzed. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 3, pp. 28–34, March, 2007.     

Mechanical properties of Cu-Al-Fe alloys

Conclusions The strength and ductile characteristics of Cu-Al-Fe alloys with 8–14% Al and 13–40% Fe are superior to those of bronze BrAZh9-4. The properties of these alloys can be varied within wide limits by means of heat treatment.State Scientific-Research and Design Institute of Alloys and Treatment of Nonferrous Metals. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 3, pp. 45–47, March, 1979.     

Fatigue properties of TiAl alloys

The fatigue properties of TiAl alloys, namely fatigue life, cyclic stress–strain behaviour and fatigue crack growth resistance are reviewed in the present paper. The influence of different parameters (microstructure, defects, temperature and environment) on these properties is examined. Finally, some considerations on the fatigue reliability of TiAl components are proposed.     

Thermoelectric properties of rare-earth alloys

The electrical resistivity, thermal conductivity, and thermopower have been measured for a large number of newly synthesized metallic compounds and alloys of simple, transition, and rare-earth elements. The maximum room-temperature values of the thermoelectric figure of merit ZT for the presented systems are about 7%. The temperature dependences of the resistivity and thermoelectric power have been discussed. Particular attention has been given to possible manifestations of the Kondo effect and intermediate valence including those in systems based on silicides and nickelides of cerium.