Research and development of low activation V-based superconducting materials based on the requirement for an advanced fusion reactor application

Based on a study low activation superconducting materials, we have selected the V-based Laves phase (V2(Hf, Zr)) compound superconductor from many V-based compound superconductors because of its high upper critical field (Hc2) exceeding 20 T. The fabrication, microstructure and superconductivity of V2(Hf, Zr) multifilamentary wire made through rapidly heating/quenching (RHQ) process were investigated. Based on the SEM observations, it was confirmed that the thick reaction layer within about 10 μm was formed on the boundary of powder mixture filament and V matrix after the RHQ. The Tc values were increased by additional annealing and showed about 8 K which value agreed well with that of arc-melted V2(Hf, Zr).