V3Ga micro-composites conductors: Preparation and superconducting properties

The powder metallurgical preparation of Nb3Sn microcomposite wires is considered to represent an attractive alternative to the conventional processing of Nb3Sn multicore conductors. In this contribution the analogous preparation of V3Ga microcomposites is described in detail. The method is based on the hot extrusion of Cu-V powder mixtures and a subsequent cold deformation without intermediate anneals, whereby the V particles are drawn into 100 - 500 nm thick fibres. After Ga charging, the V3Ga phase forms during a reaction treatment at temperatures between 550 and 600°C. For Cu-30 wt.% V + Ga overall critical current densities Jc(at 4.2 K) reach values of 4 × 10⁸A/m²at 16 T, with an (extrapolated) upper critical field of 23 T. They lie well above those obtained for Nb3Sn micro-composites, in particular in the high field region.