Development of Long-length Rapid-Heating, Quenching and Transformation (RHQT) Processed Nb3Al Conductors

A rapid-heating, quenching and transformation annealing (RHQT) processed Nb3Al conductor has been developed as a promising candidate for a high-resolution NMR superconducting magnet, because of its large critical current densities and n -values. Establishment of a large-billet extrusion, uniform RHQ operation, transformation heat treatment and subsequent Cu-clad stabilizing that are key issues of the long-length processing allows a fabrication of a four hundred meter long RHQT Nb3Al conductor, and thereby its coil application comes in sight with reality. In the present review article, current status of long-length RHQT processed Nb3Al conductors is described.