金属材料研究所における小型冷凍機冷却超伝導マグネットの強磁場化 強磁場マグネット用高強度Ｎｂ３Ｓｎ超電導線材の開発―Ｃｕ‐ＮｂＴｉ系化合物強化型Ｎｂ３Ｓｎ超電導線―

Abstract

Nb3Sn superconducting wires reinforced with a CuNi-NbTi compound have been developed. The critical current density of the CuNi-NbTi reinforced Nb3Sn superconducting wire with a is the same as conventional Nb3Sn wire without reinforcement, but 0.2% proof stress is twofold higher that of the conventional wire. To investigate distribution of Cu, Ni, Nb and Ti in the CuNi-NbTi wire, observation using EPMA (Electron Probe Micro Analyzer) was performed. Based on these developments, an industrial-scale CuNi-NbTi/Nb3Sn wire was successfully. The critical current density and 0.2% proof stress at room temperature of the industrial-scale wire were greater than 600 A/mm2 at 12 T and 350 MPa, respectively. The high-strength Nb3Sn wires were applied in the manufacture of a cryocooled hybrid magnet and 18 T cryocooled superconducting magnet at Tohoku University.