Development of high performance Nb3Sn superconducting wire by using Ti-based compound dispersive bronze alloys

2014 Fiscal Year Final Research Report

• Project/Area Number: 23560854
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Structural/Functional materials
• Research Institution: National Institute for Materials Science
• Principal Investigator: KIKUCHI Akihiro 独立行政法人物質・材料研究機構, 超伝導線材ユニット, 主席研究員 (50343877)
• Project Period (FY): 2011-04-28 – 2015-03-31
• Keywords: Nb3Sn / ブロンズ / 高Sn濃度 / Ti添加 / 多芯線材 / 熱間押出 / 塑性加工性 / 組織制御

Outline of Final Research Achievements

The bronze-processed Nb3Sn wires are being used for the high field magnet applications. A tin content in bronze alloys is probably the most effective approach for increasing the critical current density and it affects the mechanical property and workability of bronze billets. The maximum solubility of tin in the ductile copper (alpha phase) is 15.8 mass% around 550 oC. An increasing of tin content over solubility limit creates the coarse delta phase, which is quite hard and brittle intermetallic compound. In this study, the new high tin bronze alloys having 18.5 mass%Sn have been developted. It shows a good elongation of nearly 10 % at room temperature. The coarse delta phase disappeared perfectly with appropriate Ti addition, and they replaced finer Cu-Sn-Ti ternary precipitates. In addition, multifilamentary wires were successfully fabricated. Nb3Sn layer Jc (4.2K, 12T) was 2800-3000 A/mm2, which was 1.5 times higher than that for the wire used 16 mass%Sn bronze.

Free Research Field

超伝導材料