Stress/strain dependence of critical current in Nb3Sn superconducting wires stabilized with Cu-Nb microcomposites - effect of Nb content

The effects of niobium content in the Cu-Nb microcomposite on the mechanica l property and the axial tensile or transverse compressive stress/strain ch aracteristics of the critical current I-c in a bronze processed Nb3Sn multi filament superconducting wire with the Cu-Nb microcomposite were evaluated at a temperature of 4.2 K in a magnetic held of 14 T. An increase in niobiu m content increases the 0.2% proof stress as well as both tensile and trans verse compressive stress tolerance of I-c of the wire. High yield stress va lue 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 wi re as compared to those in the Cu stabilized wire. An increase in niobium c ontent in Cu-Nb microcomposite, however, decreases them due to decrease in the coefficient of thermal expansion. (C) 2001 Elsevier Science Ltd. Al rig hts reserved.