Current Status of the R & D on Jelly-roll Processed Nb₃Al Conductors

Abstract

Nb₃Al superconductors have a strain tolerance superior to Nb₃Sn superconductors. Nb₃Al superconductors have been expected to be useful for high-field applications, such as high-energy physics (particle accelerators) and fusion reactors. In this paper, Nb₃Al wire processing technologies are summarized, and the properties of Nb₃Al strands made by the jelly-roll process are described. The jelly-roll process was suitable to develop copper-stabilized multifilamentary composites. For the high-energy physics application, a Rutherford-type cable conductor was developed. For the fusion reactor application, a chrome-plated strand with a critical current density performance of at least 600A/mm² at 4.2K and 12T was developed, and 230km strands, the world's first mass-produced Nb₃Al wire, were fabricated for the Insert Coil of ITER/EDA.