Nb3Sn(Ti) powder metallurgy processed high field superconductors

Powder metallurgy processed Nb3Sn(Ti) superconducting wires were fabricated with Sn x wt. % Ti cores for 0≤x≤3, 16 or 22 vol % cores, and a Cu 45 wt. % Nb composite. The processing used swaging, cold hydrostatic extrusions, wire drawing and heat treatments of 750 °C for two to four days. Nominal areal reductions of 104 were used. Hydride-dehydride Nb and rotating electrode processed Nb powders gave the same performance. Overall critical current densities Jc were measured between 4.2 and 1.8 K for applied fields up to 23 T. Jc increased with increased Ti and/or Sn content. The Nb3Sn(Ti) wires using a Sn 3 wt. % Ti, 22 vol % core gave Jc >104 A/cm2 at 20 T and 4.2 K and Jc =104 A/cm2 at 23 T at 1.8 K. Removal of the precompression of the matrix increased Jc by about a factor of 2 at 20 T and 4.2 K.