Texture and mechanical properties of tape substrates from binary and ternary copper alloys for second-generation high-temperature superconductors

Abstract

The process of texture formation in tapes made of a number of binary and ternary copper alloys upon cold rolling to degrees of deformation of 98.6–99% and subsequent recrystallization annealing has been studied. The possibility of designing multicomponent alloys based on the binary Cu-30% Ni alloy additionally alloyed with elements that strengthen the fcc matrix, such as iron or chromium, has been shown. The opportunity of obtaining a perfect cube texture in a thin tape made of binary and ternary copper alloys opens prospects for their use as substrates in the technology of second-generation HTSC cables. Optimum regimes of annealing have been determined, which make it possible to obtain in the Cu-M and Cu-(30–40)Ni-M (M = Fe, Cr, Mn) alloys a perfect biaxial texture with the fraction of cube grains {001}〈100〉 on the surface of the tape more than 94%. The estimation of the mechanical properties of the textured tapes of the investigated alloys demonstrates a yield strength that is 2.5–4.5 times greater than that in the textured tape of pure copper.