基礎講座
金属系超電導線材 [2]
合金系線材
2010 年 45 巻 1 号 p. 2-14
詳細
2010 年 45 巻 1 号 p. 2-14
The procedure for mass producing Nb-Ti alloy has been established, where the development of high-homogeneity ingots improves the reliability of the alloy. The manufacturing process of fine filamentary wires of long length has also been optimized. The Nb-Ti wires can be used up to 9 T at 4.2 K. The non-Cu Jc of the wires at 6 T and 4.2 K reaches 2,500 A/mm2 through the combination of cold drawing and heat treatment. The microstructure of resulting Nb-Ti wires is very complicated, containing dislocation sub-bands and α-Ti precipitations. The structure and flux pinning in fine filamentary wires have been studied in detail. The introduction of artificial pinning centers, for example Nb, yields an appreciable increase in Jc. Ultra-thin filamentary Nb-Ti wires with low AC loss have also been successfully fabricated. Nb-Ti based ternary alloys, for example Nb-Ti-Ta and Nb-Ti-Hf, have been studied, aiming for the enhancement of Bc2. The microstructure and performance of alloys other than Nb-Ti, for example Nb-Zr, V-Ti and Mo-Re, are also described in this article.
