Superconducting properties of a copper-ternary alloy

The superconducting properties of a copper-ternary alloy of the type Cu93Nb5Sn2, subjected to a variety of mechanical and heat treatments, are discussed. The as-cast alloy does not turn superconducting down to 4.5K; but the cold-work and subsequent prescribed heat treatments are found to raise the transition temperature Tsub(c) to values as high as 18.1K and the critical current density Jsub(c) (of the Nb3Sn formed during annealing) to a value of 3.6x105Acm-2(at 4.2K and 30kOe). Various possibilities to improve Jsub(c) of this alloy to still higher values are discussed. The as-cast alloy is ductile, easy to draw, and economical from a technical point of view, and the annealed wires and strips are flexible enough for winding. (author)