Current densities of commercial NbTi-based alloys for high field applications

The critical current densities at high fields of 8 NbTi-based alloys are presented. Of those eight alloys, five contained tantalum in amounts varying from 0.5% up to 25%. The processing of the samples was optimized for high field reduced temperature operation. All of the alloys were shown to have useful current densities for fields up to 12 tesla at temperatures lower than 3 K. The alloys with large amounts of tantalum had significantly higher current densities than did the binary alloys at the high fields. As an example, the critical current density of 32%Nb-43%Ti- 25%Ta is up to 75% greater than that of the binary alloys at 12 tesla and 2 K. Moreover, the useful range of current densities can be extended to at least 13 tesla for some of the ternary alloys.