Structure and Performance of ${\hbox {Nb}}_{3}{{\hbox {Sn}}}$ Superconducting Wires Prepared From Sn-Based Alloy Sheets

Sn-based sheets with Ta, B or Nb particle dispersion have been prepared from consolidated alloys. A small amount of Ti addition strengthened the bonding between dispersed particles and the Sn matrix, which improved the workability of the sheet. The sheet was laminated with a Nb sheet, and wound into a Jelly Roll (JR) composite. The composite was easily fabricated to a wire without intermediate annealing. Thick and uniform Nb₃Sn layers with nearly stoichiometric Sn concentration were synthesized by the mutual diffusion between Nb and Sn-based alloy layers. An offset Tc of ~18.1 K and an offset Bc2 (4.2 K) of ~26.5 T have been obtained after the heat treatment. The non-Cu Jc of the wires increased with decreasing the wire diameter. A non-Cu Jc of ~150 A/mm² has been obtained at 4.2 K and 22 T. The Sn-Ta, Sn-B and Sn-Nb based sheet JR wires exhibited similar microstructures and superconducting performances.