The prebending strain effect on Nb3Sn superconducting cabling conductors

The prebending strain effect is that the repeated bending load at room temperature enhances superconducting properties of practical Nb3Sn wires. The authors are now investigating the application of the effect to practical superconducting cabling conductors for high field superconducting magnets. Large current capacity and high strength are required for superconducting cabling conductors to make large scale and high field magnets. The superconducting cabling conductor with high strength Nb3Sn wires will be useful for making high field magnets. The prebending strain effect was applied to a cabling technique with Nb3Sn wires. High strength Nb3Sn wires reinforced with CuNb composite and conventional Nb3Sn wires without reinforcement were prepared, which were heat-treated at 943 K for 345.6 ks. Both wires were bent by 10 pulleys to give 0.8% prebending strain. After the prebending treatment the wires were assembled and fabricated 3-strand cables and 7-strand cables. The cables with high strength Nb3Sn wires showed the enhancement of critical currents even after the cabling process. The results imply that the prebending treatment is applicable to the fabrication of cabling conductors for making a high field superconducting magnet.