Fabrication of flexible superconducting Nb3Al tape

Flexible tapes of Nb3Al were prepared by cold welding sheets of niobium and aluminum in a rolling mill followed by a brief high-temperature heat treatment. They were also prepared by a vapor deposition process followed by heat treatment under a high aluminum vapor pressure. Superconducting layers were typically 1 mil thick and had T/subc/'s in the range 16--18 K. J/subc/(H) measurements indicate that properly prepared Nb3Al tapes can carry large current densities (8times104 A/cm2 at 70 kOe). Present research shows that considerable metallurgical difficulties, associated with the high reaction temperatures and brittleness of the Nb3Al phase, need to be overcome before these processes can become commercial