Influence of strain on Nb3Sn multifilament conductors

Abstract

In Nb₃Sn multifilament conductors, the superconducting component is subjected to compressive stress. This affects both the superconducting critical temperature and the critical current. After removal of the matrix by a chemical treatment, the degradation of the critical temperature is partly reversed and the critical current increases. With the aid of a model, which takes into account the plastic behavior of the components, the strains resulting from thermal shrinkage are calculated. The resulting degradation of T_c and the measured T_c values are in fairly good agreement. The strain‐dependent change of critical current is solely caused by a change of the upper critical field; the pinning force function remained almost unaltered.