Strain effects of high strength Nb3Sn wire reinforced by jelly-rolled Nb/Cu composite and modification of the reinforcement

We are in the process of developing high strength Nb3Sn wires reinforced by unique Nb/Cu composites made in a jelly-rolling process to miniaturize hig h field magnets. A bronze-processed (Nb,Ti),Sn superconducting wire incorpo rating the composite with a high Nb volume fraction has been made. The wire has shown a high 0.2 % proof stress at 4.2 K of 350 MPa. The strain effect s such as uni-axial strain dependence and bending strain tolerance on the c ritical current were examined this time. The influence of the Nb volume fraction in the jelly-rolled composite reinf orcement was also investigated to improve the electrical conductivity of th e reinforcement.