Stress/strain dependence of critical current in Nb3Sn superconducting wires stabilized with Cu–Nb microcomposites – effect of Nb content Original Research Article

The effects of niobium content in the Cu–Nb microcomposite on the mechanical property and the axial tensile or transverse compressive stress/strain characteristics of the critical current Ic in a bronze processed Nb3Sn multifilament superconducting wire with the Cu–Nb microcomposite were evaluated at a temperature of 4.2 K in a magnetic field of 14 T. An increase in niobium content increases the 0.2% proof stress as well as both tensile and transverse compressive stress tolerance of Ic of the wire. High yield stress value of the Cu–Nb microcomposite increases the strain at peak Ic, εm, as well as the reversible strain limit of Ic, εirr in the wire as compared to those in the Cu stabilized wire. An increase in niobium content in Cu–Nb microcomposite, however, decreases them due to decrease in the coefficient of thermal expansion.