Hot extrusion and fabrication of powder metallurgy processed superconductors

In order to demonstrate the potential of powder metallurgy (P/M) process for fabrication of high field superconductors, intermediate scale (5 cm o.d. 15 cm long) billets were fabricated and processed industrially by hot extrusion. Precompacted powder composites of Cu-45wt%Nb and Cu-45wt%(Nb-1.2wt%Ti), each weighing more than 2kg, were extruded as solid or tubular bars. Sections of the extruded Cu-Nb and Cu-Nb(Ti) bars were successfully processed to 0.25 mm o.d. wires. Internal Sn sources were used to produce multifilamentary Nb3Sn and Nb3Sn(Ti). The high field critical current density was comparable to that obtained from small scale cold hydrostatic extrusion processing. The results suggest that large scale extrusion processing should produce high performance P/M processed superconductors.