Preparation of Nb3(Sn-In) wires by a ductile fabrication process

High critical field and high critical current Nb
3
(Sn-In) multifilamentary wires were fabricated using an improved Sn base alloy. Nb rods with one or nineteen holes were impregnated with a ductile Sn-Cu-In alloy and reduced to final size wire by swaging and cold drawing without intermediate annealing. Addition of In and Cu to the Sn substantially improved the high field critical current and upper critical field. At 4.2 K, the nineteen core wire reacted at 900°C for 9 hours has an overall critical current density of 10
⁴
A/cm
²
at 18 T and an extrapolated upper critical field of 25.5 T.