Stabilization and coil performance of RHQT-processed Nb/sub 3/Al conductors
Stabilization and coil performance of RHQT-processed Nb/sub 3/Al conductors
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DOI：
10.1109/77.919952
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发表时间：
2001-03
影响因子：
1.8
通讯作者：
T. Takeuchi;N. Banno;T. Fukuzaki;T. Kiyoshi;S. Matsumoto;H. Wada;K. Aihara;Y. Wadayama;M. Okada;K. Tagawa;K. Nakagawa
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文献类型：
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作者：
T. Takeuchi;N. Banno;T. Fukuzaki;T. Kiyoshi;S. Matsumoto;H. Wada;K. Aihara;Y. Wadayama;M. Okada;K. Tagawa;K. Nakagawa
采用凝胶轧(JR)Nb/Al复合材料的线材经快速加热、淬火、相变-退火形成Nb/Sub3/Al相(RHQT工艺)，可制备出高性能的Nb/Sub3/Al超导体。因此，由于导体被加热到2000/spl deg/C，远远高于铜的熔点，铜稳定剂需要在淬火和退火之间通过机械包覆的方法在外部结合。这种适当的形变促进了无序体心立方相的转变，从而提高了临界电流密度J/subc/。采用风反应法制备了螺线管线圈：将铝包覆铝芯绝缘导线(1.61/sup w//spl次/0.71/sup t/mm/sup 2/)缠绕成一个线圈(19.7/40.8/sup/spl phi/spl次/49.7/sup H/mm)，在800/spl deg/C下变形，浸渍蜂蜡。合成的线圈在2.1K时的电流为179A，超导后备磁场为21.2T，产生了额外的1.3T。22.5T的总磁场是金属超导线圈有史以来最高的记录。
A Nb/sub 3/Al superconductor based on jelly-rolled (JR) Nb/Al composites of high performance can be fabricated by rapid-heating and quenching of a wire of such composites with subsequent transformation-annealing to form the Nb/sub 3/Al phase (RHQT process). Since the conductor thereby is heated up to 2000/spl deg/C, far above the melting point of Cu, the Cu stabilizer needs to be externally incorporated by a mechanical-cladding method between quenching and annealing. Such an appropriate deformation promotes the transformation from a disordered bcc phase, and thereby enhances the critical current density J/sub c/. A solenoid coil was fabricated by a wind-and-react method: the Cu-clad conductor (1.61/sup w//spl times/0.71/sup t/ mm/sup 2/) with Al/sub 2/O/sub 3/ yarn insulation was wound into a coil (19.7/40.8/sup /spl phi///spl times/49.7/sup H/ mm), transformed at 800/spl deg/C, and impregnated with beeswax. The resultant coil, while carrying a current of 179 A at 2.1 K in a superconducting back-up field of 21.2 T, generated an additional 1.3 T. The total magnetic field of 22.5 T is the highest record ever for a metallic superconducting coil.