Properties of Nb3Sn discrete filamentary wires by a new reliable process

We have developed a new process to improve drawbacks of In Situ technique and powder metallurgical processing. Chopped composite wires were employed instead of Nb dispersed Cu matrix ingots or Nb and Cu powders, and then the tin source for internal diffusion was prepared in the matrix. The wire by the new process had very well workability through the process, because Nb filaments were very ductile compared with filaments from powders. And the filament size control which was required for large scale production, was possible. By the critical current measurement, a 0.29 mm wire had critical current density of 4 × 10⁴A/cm²at 9 T, and the critical current density was increased about three times by the reduction of the wire size from 0.5 to 0.29 mm. Although the present value of the critical current density are not optimized, the higher critical current density will be promised by increasing tin content and reduction ratio.