Effect of rapid heating, quenching and transformation conditions on the superconducting properties and microstructure of Jelly-Roll processed Nb3Al superconductors
Effect of rapid heating, quenching and transformation conditions on the superconducting properties and microstructure of Jelly-Roll processed Nb3Al superconductors
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DOI：
10.1088/0953-2048/15/10/307
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发表时间：
2002-10
影响因子：
3.6
通讯作者：
T. Fukuzaki;T. Takeuchi;N. Banno;K. Tagawa;N. Tatsumi;H. Ogiwara;H. Wada
中科院分区：
文献类型：
--
作者：
T. Fukuzaki;T. Takeuchi;N. Banno;K. Tagawa;N. Tatsumi;H. Ogiwara;H. Wada
采用快速加热、淬火和转变(RHQT)工艺制备了具有优良超导性能的凝胶辊法制备的Nb3Al超导体。为了制备出具有均匀超导性能的长丝，RHQT条件的优化尤为重要，因为RHQT条件决定了最终的微观结构和超导性能。本文研究了RHQ和相变退火条件对样品微观结构和超导性能的影响，确定了最佳工艺条件。在对RHQ处理的研究中，我们发现RHQ条件根据焦耳加热电流(IRHQ)被划分为四个区域。在最佳区，线材从体心立方固溶体扩展到25at%Al以上的温度淬火，相变退火后的临界电流密度(JC)的分散几乎可以忽略不计。在形变和相变热处理的研究中，我们发现过饱和固溶体的形变改善了所得到的超导性能，并防止了在升温速率较慢时发生的超导性能退化。
A Jelly-Roll processed Nb3Al superconductor with excellent superconducting properties has been fabricated by the process of rapid heating, quenching and transformation (RHQT). In order to fabricate a long length of wire with homogeneous superconducting properties, the optimization of the RHQT conditions is particularly important because RHQT conditions determine the final microstructure and superconducting properties. In this paper, we have studied the variation of microstructure and superconducting properties with RHQ and transformation annealing conditions, to determine the optimum processing condition. In the study of the RHQ treatment, we found that the RHQ conditions are divided into four regions according to the joule heating current (IRHQ). In the optimum region, the wire is quenched from the temperature in which a bcc solid solution extends to more than 25 at%Al, and the scatter of critical current density (Jc) after transformation annealing is almost negligible. In the study of the deformation and transformation heat treatment, we have found that the deformation of the supersaturated solid solution improves the resultant superconducting properties, and prevents degradation of superconducting properties that occurs when the temperature ramp-up rate is slow.