SUPERCONDUCTING PROPERTIES AND STRAIN EFFECTS IN HIGH FIELDS FOR BRONZE-PROCESSED MULTIFILAMENTARY (NB,TI)3SN WIRES AND COMPOSITE-PROCESSED ULTRAFINE FILAMENT NB3AL WIRES

Multifilamentary (Nb,Ti)3Sn wires supplied for Japan VAMAS standard samples showed non Cu Jc's over 350 A/mm2 at 15 T, after optimum heat treatments at temperatures from 650-degrees-C to 700-degrees-C. The upper critical field Hc2 is extrapolated to about 25 T, for these wires. The uniaxial strain dependence of Ic at 14 T for the (Nb,Ti)3Sn wire was observed to be greatly reduced, due to the enhancement of Hc2 resulting from the incorporation of Ti into the Nb3Sn layer. The Nb3Al wire shows substantially smaller strain sensitivity of Ic as compared to that for the (Nb,Ti)3Sn wire.