Influence of cyclic loading at room temperature on the critical current at 4.2 K of Nb 3Sn superconducting composite wire

Abstract

The influence of cyclic loading at room temperature on the critical current at 4.2 K of bronze-processed multifilamentary Nb 3Sn superconducting composite wire was studied. After the first cycle, the critical current and upper critical magnetic field increased, reaching a maximum and then decreased with increasing applied stress. After the second and following cycles, the changes were small when the applied stress was not high enough to cause damage to the Nb 3Sn. These results can be described well quantitatively by substituting the strain values of Nb 3Sn calculated in this work into Ekin's scaling law for the strain effect. When the applied stress was high enough to cause damage to the Nb 3Sn in the first cycle, the critical current decreased with increasing numbers of cycles.