Fabrication of Nb3Al superconducting wire through gas jet quenching method

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K05088
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26050:Material processing and microstructure control-related
• Research Institution: National Institute for Materials Science
• Principal Investigator: KIKUCHI Akihiro 国立研究開発法人物質・材料研究機構, 機能性材料研究拠点, グループリーダー (50343877)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 超伝導線材 / Nb3Al / 通電加熱 / ガス噴射急冷 / 冷却速度 / 極細線

Outline of Final Research Achievements

High-temperature heat treatment at about 2,000℃ is required to produce high-performance Nb3Al. On the other hand, the high-temperature heat treatment supports the crystal grain growth and reduces the critical current density. In order to simplify the process of energization heating and liquid metal quenching so far, we considered the use of gas injection quenching. In order to obtain high cooling efficiency, we have made ultra-fine processed wires and succeeded in prototyping a long ultra-fine Nb/Al precursor wire with 50 microns in OD and over 1,000 meters in length. It was found that additional study of advanced tension control is required to energize and heat this ultra-fine wire. But since the diffusion distance between Nb and Al is significantly shortened in the ultra-fine wire, a reduction of both heat treatment temperature and time could be expected. It could be found the possibility of the new mass-production process for Nb3Al wires without special heat treatment.

Free Research Field

超伝導線材

Academic Significance and Societal Importance of the Research Achievements

脱炭素社会の実現に向けて将来のベース電源として期待される核融合炉や、素粒子物理のみならず重粒子線照射や核変換技術などの産業応用も期待される加速器などでは、高磁場下でも高い臨界電流密度が得られる高性能超伝導線材が必要とされている。特に電磁力に対して強いNb3Al線材はその実用化が長年待望されているが、線材化プロセスが複雑で実用化が難航している。本研究で得られた成果は、Nb3Al線材の製造法を簡素化させるだけでなく、極細径であることから可とう性の向上も図ることができる。線材のハンドリングを大幅に改善して巻き線加工が容易になり、高性能超伝導マグネットの製造コストの低減に貢献することも期待できる。