Microstructure and superconductivity of V-based Laves-phase superconductor tape synthesized by a rapidly-heating/quenching process

Abstract The vanadium (V)-based Laves-phase compound is suitable for use as a high field superconductor for advanced fusion reactors because it shows radiation resistance and lower induced radioactivity in the fusion neutron irradiation condition compared with Nb-based A15 superconducting wires. We investigated the fabrication of V2(Hf,Zr) tapes by applying the rapidly-heating/quenching (RHQ) process. Pure Hf, Zr, and V powders were mixed and ball-milled, and then packed into pure Ta tubes. This powder-filled tube was cold-drawn and then flat-rolled into tapes of 0.2 mm in thickness. Precursor tape was set in the RHQ apparatus, then was continuously heated for 0.25 s and subsequently quenched into a liquid Ga bath. The highest temperature during the RHQ treatment was varied up to 2200 °C. Some specimens were additionally annealed in vacuum after the RHQ. We found a Tc value of about 8.88 K was obtained after the annealing.