Direct solid-state precipitation-processed A15 (Nb3A1) superconducting material

A ’’solid-state precipitation’’ process was used to prepare superconducting tapes containing Nb3Al in a niobium matrix. Small ingots of Nb–(17–19 at . %)Al were prepared by arc melting, homogenizing, quenching, warm rolling into tape, and aging at 750–900°C to precipitate the A15 phase. Transmission electron microscopy studies revealed Nb3Al precipitation in fine particles which formed a semicontinuous network over subgrain boundaries fromed by the recovery of deformation-induced dislocations. Promising high-field critical currents were obtained (Jc∼104 A/cm2 in a field of 14 T at 4.2 K).