Development of Nb₃Sn Superconducting Wire Using an In-Situ Processed Large Ingot

Abstract

The in-situ process for Cu-Nb has been developed on a laboratory scale, and recently several groups have produced multifilamentary wires with overall critical current density comparable to commercial continuous-fiber multifilamentary materials.[1] The mechanical properties of the in-situ wires are considerably better than those of the conventional multifilamentary superconducting wires.[2] For practical applications, it is necessary to demonstrate that the in-situ process can be adapted to industrial scale. Generally, small-diameter in-situ rods were chosen because good quality control of the Cu-Nb alloys fabrication could be achieved on the basis of prior experience with small chill casting.[3] To demonstrate the feasibility of scale-up Cu-Nb ingots were made by smelting and casting by the calucia process. In this paper we report our results on the development of this in-situ Nb₃Sn wires.