Structure and High-Field Performance of New ${\hbox {Nb}}_{3}{\hbox {Sn}}$ Wires Fabricated From Sn-Based Alloys

Sn-Ta based quaternary alloys were prepared by the reaction of constituent metal powders. The alloys were fabricated into sheet or rod forms. In addition, Sn-Ti based ternary alloys prepared by melt and cast procedure were fabricated into sheets. Jelly Roll (JR) composites were prepared using Sn-based alloy sheet and Nb sheet, and then fabricated into wires. A Bc₂ (4.2 K) of 26.9 T (mid) has been obtained in the JR wire using Sn-Ta based alloy sheet. Thick Nb₃Sn layers were formed by the mutual diffusion between Sn-based alloy sheet and Nb sheet. Stoichiometric Sn concentration with no gradient was obtained throughout the Nb₃Sn layers, which may be the main origin of excellent high-field performance of the JR wires. Meanwhile, 19 and 37 filamentary Nb₃Sn wires have been fabricated using Sn-Ta based alloy rods. An equivalent high-field performance has been obtained in the multi-rod wires as that of JR wires.