Mechanical Properties of (Bi,Pb)-2223 Multifilament Tapes with Ag-Alloy Sheath

Ag-Mg-V alloy is prepared and investigated to develop a new sheath alloy used for BSCCO tapes. Bi-2223 Ag/AgMgV and Bi-2223 AgMgV/AgMgV tapes are studied with the help of stress-strain measurement, optical microstructure and critical current I_c. The value of I_c at 77K and at magnetic field B=0 is obtained to be 90A/cm² for the samples of Bi-2223 Ag/AgMgV tapes, which is higher than that of Bi-2223 AgMgV/AgMgV tapes (72A/cm²). The resistance of AgMgV alloy, up to 0.37μΩ.cm at 77K, is higher than that of pure Ag (0.28μOmega.cm) after annealed at 840°C for 40h, which is studied for reducing the ac loss. The values of the fracture strength and the maximum strain are 86MPa and 0.50% for Bi-2223 Ag/AgMgV tapes and 108MPa and 0.33% for Bi-2223 AgMgV/AgMgV tapes, respectively.