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

Abstract With extremely high critical current density ( J c ) and excellent strain tolerance, Nb 3 Al superconductor is considered as an alternative to Nb 3 Sn for application of high-field magnets. However, owing to their complex structure, Nb 3 Al superconducting wires can hardly meet the requirement of engineering application at present. In this work, a novel simple-structured Nb 3 Al 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 Nb 3 Al long wire has the T c of 13.4 K and J c of 4.7 × 10 4  A/cm 2 at 4.2 K and 12 T. These suggest that with further optimization, the simple-structured Nb 3 Al superconducting wires are very promising to fabricate the km-grade long wires to meet the requirement of engineering application.