Investigation on mechanical properties of Nb3Sn multifilamentary wires

The mechanical properties of multifilamentary Nb3Sn wires have an important role in their application in large scale magnetic systems. The influence of heat treatment schedules and design factors on the mechanical properties of rectangular and round section bronze route wires was investigated. Ultimate tensile strength, yield strength and elongation of stabilized and nonstabilized wires 0.4 mm x 4 mm in section and 0.8--1.5 mm in dia containing 4000--14,000 Nb filaments before and after heat treatment were studied. It was shown that a change of the wire design, volume fraction of copper, heat treatment regimes influence strongly on strength and plasticity of wires. The level of the mechanical properties of stabilized wires depends on the volume fraction and location of stabilizer in the section of Nb3Sn wire