Incorporation of stabilizer to rapid-quenched and transformed Nb/sub 3/Al multifilamentary superconductors

A Nb/sub 3/Al superconducting conductor based on Jelly-Rolled (JR) Nb/Al composites is fabricated by the rapid-heating and quenching of a wire of such composites with subsequent transformation-annealing to form Nb/sub 3/Al phase. Since the conductor is heated up to 1900/spl deg/C, far above the melting point of Cu, during fabrication, Cu stabilizer cannot directly be included as a basic composite constituent. In the present study, attempts have been made to incorporate the stabilizer to the Nb/sub 3/Al conductor. In a mechanical-cladding method, the as-quenched composite is wrapped longitudinally with a Cu tape, and groove-rolled for mechanical bonding. For internal stabilization, Jelly-Rolled Nb/Al filaments are isolated from the stabilizers by a Nb-filaments barrier and the formation of unwanted Nb-Al-Cu (Ag) compounds are prevented. Ag-stabilizer, little reactive with Nb, can dramatically decrease the Nb-barrier thickness required and allows the increase in the volume fraction of the stabilizer instead.