Abstract
In order to develop a Nb3Sn coil using a react and wind method, it is important to clarify the influence of bending strain because the superconducting characteristics of Nb3Sn are very sensitive to stress and strain. We investigated the effect of prebending strain εpb, which means repeated bending loads, from 0% to 1.5% for superconducting wires. We found that Ic, Tc and Bc2 were enhanced by prebending strain. When the prebending strain was 0.8%, Ic values showed maximum enhancement at a whole magnetic field for CuNb/Nb3Sn wires. For instance, Ic was approximately twice at 19 T. Bc2 increased about 1.5 T at a whole temperature when εpb was 1.0%. Tc increased from 17.5 K to 17.9 K at a prebending strain of 1.2%.
