Stress/strain dependence of critical current in Nb_3Sn superconducting wires stabilized with Cu-Nb microcomposites - effect of Nb content

摘要

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 I_c in a bronze processed Nb_3Sn 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 percent proof stress as well as both tensile and transverse compressive stress tolerance of I_c of the wire. High yield stress value of the Cu-Nb microcomposite increases the strain at peak I_c, #epsilon#_m, as well as the reversible strain limit of I_c, #epsilon#_(irr) 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.