Fabrication and Superconducting Properties of Rod‐In‐Tube Multifilamentary Nb3Al Wire With Rapid Heating and Quenching Heat‐Treatment

In this paper, we reported the recent progress in developing practical kilometer-length rod-in-tube (RIT) multifilamentary Nb₃Al superconducting wires at WST, which included the preparation of Cu/Nb-Al precursor wires, design and manufacture of rapid heating and quenching (RHQ) equipment, and RHQ heat-treatment process of Nb₃Al wires. Superconducting properties and microstructure of the RIT Nb₃Al wires have been discussed. By measuring magnetization and transport critical current properties of Nb₃Al wires, it is found that, for all the samples, the onset superconducting transition temperature T_c reaches 16.8-17.3 K, and at 4.2 K and 15 T, the critical current density J_c of 830 A/mm² at the Nb₃Al wires have been achieved. This paper suggests that it is possible to develop the practical Nb₃Al superconducting wires by using the RIT Nb₃Al precursor wires, in combination with RHQ heat-treatment process.