Performance of Thin Cu-Nb/Nb3 Sn Round Wires and Tapes Pre-Bent for R&W Process

Masahiro Sugimoto, Daisuke Asami, Hiroyuki Fukushima, Kiyoshige Hirose, Tomoya Kato, Hirokazu Tsubouchi, Satoshi Awaji

Research output: Contribution to journalArticlepeer-review


Cu-Nb/Nb3Sn wires have high mechanical strength and large compressive residual strain. In this study, we successfully developed thin Cu-Nb/Nb3Sn round wires and tapes to avoid the critical current (Ic) degradation caused by damage of brittle Nb3Sn filaments in React-and-Wind (R&W) process with small bending diameters. Both the Cu-Nb/Nb3Sn round wires of 0.45 mm diameter and the tapes of 0.40 mm thickness had Ic increase by pre-bending treatments up to bending strains of ±0.6% in the Nb3Sn filamentary area including the tin-diffusion barrier. The pre-bent tapes of thicknesses 0.9-0.25 mm (aspect ratio 1.5-10.2) showed higher Ic characteristics than as-reacted tapes independently of magnetic field directions. The R&W spiral coils of 39 mm diameter, which were wound with the pre-bent round wire of 0.45 mm diameter and the pre-bent tape of 0.48 mm thickness, retained higher Ic-B characteristics than those of the W&R spiral ones.

Original languageEnglish
JournalIEEE Transactions on Applied Superconductivity
Issue number4
Publication statusPublished - 2022 Jun 1


  • Cu-Nb/NbSn wire
  • Nb-rod-method Cu-Nb
  • pre-bending effect
  • react-and-wind

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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