Investigation of the magnetization and the twist pitch effect on critical current density in Nb/sub 3/Sn wires of different designs

The effect of the twist pitch on the current carrying capacity in magnetic fields of 1-12T on multifilamentary superconductors of different designs based on Nb/sub 3/Sn, that had been made by means of the bronze technique and have different parameters: volume fraction of Nb in bronze matrix (VFNb), number of filaments, wire and filaments diameters, presence of stabilization, has been studied. It has been stated that after twist pitch reaching 6d-9d mm, where d is the wire diameter, a considerable decrease of current carrying capacity in conductors of all the types (except for wires with low VFNb, less than 0.1) is observed. The application of twisting modes with the intermediate heat treatment that restores the twisted conductors plasticity, made it possible to eliminate the current carrying capacity degradation. Also, we present magnetization data and hysteresis losses in conductors of different designs.<
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