Epitaxial Tape Substrates of Perspective Ternary Alloys on Copper-Nickel Based for Superconducting Cables

摘要

The structure and process of the texture formation in tapes of ternary alloys Cu–Ni–Me (Me = Fe, Cr, V) in the course of cold deformation by rolling to ~99% and subsequent recrystallizing annealing has been studied. The transition metals with copper-nickel alloys form wider concentration areas than with pure copper. TEM-research of the structure of ternary alloys after texture-forming annealing didn’t detect any inclusions of any other type of crystal lattice. The sum of the components (S+C), those are propitious for the formation of cube texture in course of subsequent recrystallizing annealing, is higher than in pure copper. Optimum annealing conditions for the studied alloys have been determined, which have made it possible to produce the perfect biaxial structure, with a content of cube {001}100±10 grains on the surfaces of textured 99%. The possibility of achieving a perfect cube structure in thin tape made of ternary alloys on copper-nickel basis with 3d-metals (chrome, iron or vanadium) opens the prospect of using them as substrates in process of tapes of second generation high temperature superconductors manufacturing. The yield strength of the textured strips of the investigated ternary alloys is ~4 times higher than of the tape of pure copper, and ~20% higher than of the tape of the binary alloy of Cu–40% Ni. Adding of a third element to binary copper-nickel alloy, leading to additional strengthening of the tape, allows to diminish the thickness of the tape substrate and hence, the weight of the whole superconducting cable construction.