Fabrication and superconducting properties of a simple-structured jelly-roll Nb3Al wire with low-temperature heat-treatment

With extremely high critical current density (Jc) and excellent strain tolerance, Nb3Al superconductor is considered as an alternative to Nb3Sn for application of high-field magnets. However, owing to their complex structure, Nb3Al superconducting wires can hardly meet the requirement of engineering application at present. In this work, a novel simple-structured Nb3Al superconducting wires with Cu-matrix and different filament numbers were prepared by the conventional jelly-roll method, as well as a heat-treatment of 800-850 °C for 20-50 h. The results show that a 18-filament superconducting wire with length longer than 100 m can be successfully prepared by this method, and also this Nb3Al long wire has the Tc of 13.4 K and Jc of 4.7 × 104 A/cm2 at 4.2 K and 12 T. These suggest that with further optimization, the simple-structured Nb3Al superconducting wires are very promising to fabricate the km-grade long wires to meet the requirement of engineering application.