The influence of thermally induced matrix stresses on the superconducting properties of Nb3Sn wire conductors

The superconducting critical temperature, T
c
, critical current density, J
c
, and upper critical field H
c2
have been measured on bronze-processed Nb
3
Sn monofilament conductors prior to and after etching away the bronze matrix. Each superconducting parameter showed significant changes when the bronze matrix was removed. It is shown that the source of these changes are stress induced by thermal contraction of the bronze matrix.