External and Internal Stabilization Methods of RHQT Nb_3Al Superconductors

摘要

Recent progress of the externally and internally stabilized RHQT (rapid-heating, quenching and transformation) processed Nb_3Al superconductors are described and compared. The internal stabilization method has been improved by demonstrating that the Ag can be included in the strand in various places, increasing the Ag volume ratio, decreasing an overall residual resistivity of conductor, and enhancing the RRR. An attempt was made to fabricate a coil using such an internally stabilized conductor, and its result has been compared to that of Cu clad conductors.