V 3 Ga compound has a shorter radioactive decay time compared with Nb-based compounds and it will be one of the candidate superconducting magnet materials for advanced low activation fusion reactor systems. !Recently, we succeeded in developing new V 3 Ga wires, fabricated via the PIT process using high Ga content Cu-Ga compounds above Cu-Ga solid solution composition. Jc and H c2 enhancements of V 3 Ga wire due to increasing three times of the V 3 Ga volume fraction were also confirmed. For the further microstructure control, in-situ observation of diffusion reaction with increase of temperature using High-Temperature X-ray diffraction (HT-XRD) was measured. Various high Ga content Cu-Ga compounds were composed with Cu 3 Ga (β phase: 30at%Ga), Cu 9 Ga 4 (γphase: 40at%Ga) and CuGa2 (δ phase: 64at%Ga) compounds. Especially, CuGa 2 compound has much lower melting point (254 °C) compared with various Cu-Ga compounds. In the case of diffusion reaction including CuGa 2 phase, V 3 Ga phase was formed by the second step diffusion reactions; the first one is solid-liquid diffusion between the dissociated Ga liquid phase and metal V, the second one is soild-solid diffusion reaction between solid phase formed by the first step reaction and metal V.
Hishinuma, Y., Kikuchi, A., Murakami, S., Matsuda, K., Taniguchi, H., & Takeuchi, T. (2012). The formation mechanism of the higher performanceV 3 Ga phase on the high Ga content Cu-Ga compound/V diffusion reaction through the high-temperature XRD analysis. In Physics Procedia (Vol. 36, pp. 1492–1497). Elsevier B.V. https://doi.org/10.1016/j.phpro.2012.06.120