Effects of Zr, Hf and Ta Additions on Properties of in situ Cu-20%Nb–Sn Superconductors

• Published in: Transactions of the Japan Institute of Metals 1985, Vol.26(9), pp.663-671
• Main Authors: Nagata, Akihiko, Hayashi, Kazuhiko, Hanano, Toru, Izumi, Osamu
• Format: Article
• Language: English
• Subjects: Analysing. Testing. Standards; Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; copper-niobium alloy; critical current density; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; hafnium; in situ Nb3Sn superconductor; in situ superconducting composite; Materials science; Metals, semimetals and alloys; Metals. Metallurgy; Nb3Sn superconductor; Physics; Specific materials; Superconductivity; tantalum; zirconium
• ISSN: 0021-4434; 2432-4701
• DOI: 10.2320/matertrans1960.26.663

Improvements of high-field properties of in situ Nb3Sn superconductors were studied by additions of 2%Zr, 2%Hf and 2%Ta to Cu-20 mass%Nb melts. The eutectic structures around Nb dendrites were observed in all as-cast materials, and some difficulties arose from the structures in drawing the ingots with Zr and Hf into wires. The critical current densities were measured up to 15 T after various heat treatments. Additions of Zr and Hf affected a little Jc in the high magnetic field region and HC2* of in situ Cu-20%Nb–Sn superconductors. On the contrary, additions of Ta improved appreciably the high-field performance of in situ Cu-20%Nb–Sn superconductors in spite of the fact that Ta was not soluble in the Nb dendrites in the as-cast state. The highest Jc of (1–2)×108 A/m2 at 12 T and HC2* of 17.5 T were obtained on the in situ Cu-20%Nb–2Ta–Sn superconductors.