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2008/04/07(Mon) 21:57

Application of the Prebending Strain Effect in CuNb/Nb3Sn Superconducting Wires to the React-and-Wind Technique

We have successfully demonstrated that the application of the prebending strain effect on the react-and-wind (R&W) method. The CuNb/Nb3Sn superconducting wire of 1.0-mm diameter, which was heat treated at 670 ℃ for 96 hours, was repeatedly bent by using 10 fixed pulleys before the winding process. The prebending strain (epb) value was controlled by changing the pulley's diameters, which were 1.0, 0.8, 0.5 and 0%. Ic at 4.2 K and 10 T was 353 A for the coil with epb=0.8%, which was larger than that for the coil with epb=0% (331 A). In addition, those values were much larger than the critical current of the as-heat-treated wire. The results indicate that the prebending strain effect is applicable to the react-and-wind coil fabricating method.

IMR, Tohoku University: G. Nishijima, H. Oguro, S. Awaji, K. Watanabe
The Furukawa Electric Co., Ltd.: K. Miyoshi, S. Meguro

Reference: G. Nishijima, H. Oguro, S. Awaji, K. Katagiri, K. Miyoshi, S. Meguro and K. Watanabe, "Application of the prebending strain effect on CuNb/Nb3Sn super-conducting coils fabricated by a react-and-wind method," presented at the 3rd Workshop on Mechano-Electromagnetic Property of Composite Superconductors.

事前曲げ歪効果のリアクト・アンド・ワインド(R&W)法への適用に成功した.熱処理(670 ℃×96 h)済みのCuNb/Nb3Sn超伝導線(Φ1.0 mm)に10個の固定プーリを用いて繰り返し曲げ歪を与え,事前曲げ歪epb=1.0, 0.8, 0.5, 0%の単層ソレノイドを作った.4.2 K, 10 TにおけるIcはepb=0.8%のコイルが353 Aで最も高く,epb=0のコイルは331 Aであった.さらに,全てのコイルのIcは短尺試料のそれよりも大きかった.このことにより,事前曲げ歪効果がR&W法に適用可能であることを実証できた.

東北大学金属材料研究所:西島 元,小黒英俊,淡路 智,渡辺和雄