Effect of Cu Addition Into $\hbox{TiGa}_{3}$ Compound on Superconducting Properties and Microstructure of $ \hbox{V}_{3}\hbox{Ga}$ Multifilamentary Wires Synthesized Through High Ga Content Diffusion Process

The decay time of induced radioactivity in V 3 Ga is remarkably shorter than in Nb-based compounds, making the V 3 Ga compound as one of the candidate and suitable superconducting magnet materials for the future nuclear fusion system. In order to improve the superconducting properties of V 3 Ga multifilamentary wires, we investigated high Ga content TiGa 3 compound with various Cu addition as the Ga source material. The Cu additions into TiGa 3 compounds were 10, 30, and 50 wt.%, respectively. The volume fraction of V 3 Ga phase was increased with increasing of Cu addition. We confirmed that Cu addition into TiGa 3 compound promoted the formation of the V 3 Ga phase. The optimum Cu addition into TiGa 3 compound on superconducting properties was obtained to be 30 wt. %, and H c2 value of the 30 wt.%Cu sample was estimated to be above 24 T. This value was 3 T higher than conventional “Bronzed route” processed V 3 Ga wires.