Influence of Tensile Stresses on the Superconducting Temperature of Multifilamentary Nb₃Sn Composite Conductors

Abstract

The need for Nb₃Sn multifilament conductors in large magnet systems has generated interest in the mechanical and associated electrical properties of these composites. The superconducting compound Nb₃Sn in bronze-processed conductors is subjected to a compressive strain originating from the thermal contraction of the outer bronze matrix. Such compressive strains lower the compound’s superconducting temperature, T _c , and removal of the compressive strains by etching off the bronze matrix restores the original T _c Recent investigations have suggested that tensile loading of these composite superconductors can increase T _c [³] This report presents a study of T _c and its relationship to both internal prestrains and applied tensile loads at 4.2 K in Nb₃Sn composite superconductors.

Work performed under the auspices of the U. S. Energy Research and Development Administration.