Strain effects on superconducting properties in Nb3Al multifilamentary wires

Critical temperatures T/sub c/ and critical currents I/sub c/ under uniaxial tensile loading have been studied on multifilamentary Nb3Al wires fabricated by a newly developed composite diffusion process. Both T/sub c/ and I/sub c/ are monotonically decreased with applied strain, showing reversible behavior up to fracture strains of the wires at about 1.3%. These characteristics may be attributed to the composite wire structure, namely to the small difference in thermal contraction between the niobium matrix and the Nb3Al filaments, as well as to the extremely small sizes of the Nb3Al filaments