Microstructure and Superconducting Properties of V-Based Laves Phase Compound Multifilamentary Wires Synthesized by a Rapidly Heating and Quenching Process to Hf-Zr/V Composite

We have tried to study low activation superconducting materials of the many V‐based compound superconductors, and selected the V based Laves phase (V2(Hf,Zr)) compound because of its high upper critical field (Hc2) exceeding 20 T, its neutron irradiation resistance, and its low activation in the fusion reactor compared with those of Nb‐based A15 wires.The fabrication, microstructure and superconductivity of V2(Hf,Zr) multifilamentary wire synthesized by applying a rapidly‐heating/quenching (RHQ) and annealing process to the simple precursor using pure Hf and Zr mixture powder and pure V tube matrix were investigated. We found that a thick reaction layer was formed between the powder mixture filament and V matrix after the RHQ treatment and then it was increased with an increment of heating energy. Offset Tc values of samples were raised by increasing heating energy, and maximum Tc values occurred at 8.3 K. The maximum Jc value was obtained for a sample of post‐annealing at 600°C for 10 h. Jc dependence on...