1992 Fiscal Year Final Research Report Summary

Development of Cu-Nb Alloy with High Strength and High Conductivity

Research Project

Project/Area Number	03650548
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	金属加工(含鋳造)
Research Institution	TOHOKU UNIVERSITY
Principal Investigator	IKEDA Keisuke TOHOKU UNIVERSITY, DEPT. OF ENG., PROF., 工学部, 教授 (40005921)
Co-Investigator(Kenkyū-buntansha)	NISHIMURA Keio TOHOKU UNIVERSITY, DEPT. OF ENG., RESEARCH ASIST., 工学部, 助手 (00218190)
Project Period (FY)	1991 – 1992
Keywords	Cu-Nb alloy / Mechanical properties / Electric conductivity / Residual resistivity ratio / 導電率 / 残留抵抗比
Research Abstract	Mechanical properties and electric conductivities were evaluated for heavily cold-drawn wires of copper-niobium alloys containing 10, 15 and 20 wt% Nb. The strength of these alloy wires at room temperature increased with both Nb content and overall reduction of area. The maximum strength of Cu-20 wt% NNb wire reduced by 2x10^4 in cross-sectional area was 1.7 GPa, which was drastically higher than the value predicted by the rule of mixture. The strength of the Cu-Nb wire was proportional to d^<-1/2> (d;diameter of Nb filament). The strength and specific resistivity dropped by annealing. The annealing temperature where the specific resistivity began to decrease varied depending on the Nb content. The Cu-10 wt% Nb alloy wire alone presented both conductivity above 70% of pure copper and strength of more than 1 GPa. The residual resistivity ratio, R.R.R. of Cu-Nb wires was about 10, which was a tenth of the value for pure copper. This results suggests that the electron scattering on the Cu-Nb interface is considerably high. It was tried to fabricate the Cu-Nb wire by extrusion and HIP of the mixture of Cu and Nb powders. However, no sound product obtained, because of bad weldability between Cu and Nb particles.