INVESTIGATION OF THE MAGNETIZATION AND THE TWIST PITCH EFFECT ON CRITICAL-CURRENT DENSITY IN NB3SN WIRES OF DIFFERENT DESIGNS

The effect of the twist pitch on the current carrying capacity in magn etic fields of 1-12T on multifilamentary superconductors of different designs basing on Nb3Sn, that had been made by means of bronze techniq ue and have different parameters: volume fraction of Nb in bronze matr ix (VFNb), number of filaments, wire and filaments diameters, presence of stabilization, has been studied. It has been stated that after twi st pitch reaching 6d-9d mm, where d - wire diameter, a considerable de crease of current carrying capacity in conductors of all the types (ex cept for wires with low VFNb, less than 0.1) observed. The application of twisting nodes with the use of intermediate heat treatment that re stores the twisted conductors plasticity, made it possible to eliminat e the current carrying capacity degradation. Also, we present magnetiz ation data and hysteresis losses in conductors of different designs.