Study on the stability of superconducting materials

In the fiscal year of 1996, a basic investigation was made on a wire composed of supersaturated solid solution filament with an aim to produce Compacted Strand Cable, a superconducting magnet cable for nuclear fusion reactor. The formability of flattened Nb3Al wire produced via rapid quenched and transformed process was examined. The critical current density of the Nb3Al wire was not decreased by flattening molding and any field orientation anisotropy did not appeared. When it was flattened to the overall aspect ratio of 15, the distribution of bundle area became broad, resulting in a lowering of n-value. However, the n-value near to 15 may be kept by optimizing the flattening process. Any marked troubles in flattening formability were not observed for the filament level and thus, Compacted Strand Cable was suggested to be available as a large-current carrying cable. (M.N.)