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.