Reversible strain limit of critical currents and universality of intrinsic strain effect for REBCO-coated conductors
Reversible strain limit of critical currents and universality of intrinsic strain effect for REBCO-coated conductors
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DOI：
10.1088/0953-2048/22/2/025015
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发表时间：
2009-02
影响因子：
3.6
通讯作者：
K. Osamura;M. Sugano;K. Nakao;Y. Shiohara;A. Ibi;Y. Yamada;N. Nakashima;S. Nagaya;T. Saitoh;Y. Iijima;Y. Aoki;T. Hasegawa;T. Kato
中科院分区：
文献类型：
--
作者：
K. Osamura;M. Sugano;K. Nakao;Y. Shiohara;A. Ibi;Y. Yamada;N. Nakashima;S. Nagaya;T. Saitoh;Y. Iijima;Y. Aoki;T. Hasegawa;T. Kato
在日本的NEDO项目下，为了开发工业上可用的高温超导REBCO涂层导体，已经进行了深入的研究工作。最近，该项目的几个小组成功地开发了高性能涂层导体。他们的特点已被评估的机械性能和它们对临界电流的影响。根据混合规则分析了室温和77 K下的力学性能。推导了超导层的无力应变（Aff），它表示施加在超导层上的残余应力变为零时的应变。拉伸应变对临界电流的依赖性可分为弹性区和脆性区。可逆应变极限（Arev）被定义为临界电流弹性恢复到99%Ico水平的应变。在弹性区域内，临界电流表现出凸应变依赖性，这被解释为Ekin的本征应变效应。超过可逆应变极限的退化归因于超导层的断裂。本研究定量地揭示了临界电流的拉伸应变行为，并提出了可逆应变极限的合理定义。
Intensive research work has been carried out in order to develop industrially available HTS REBCO-coated conductors under the NEDO project in Japan. Recently, several groups in the project succeeded in the development of high performance coated conductors. Their characteristic features have been evaluated in terms of mechanical properties and their influence on critical currents. The mechanical properties at RT and 77 K were analyzed on the basis of the rule of mixtures. The force-free strain (Aff) was analytically deduced, which indicates the strain at which the residual stress exerted on the superconducting layer becomes zero. Tensile strain dependence on critical currents could be divided into elastic and brittle regions. The reversible strain limit (Arev) was defined as a strain at which the critical current recovers elastically to the level of 99% Ico. Within the elastic region, the critical current showed a convex strain dependence, which is explained as Ekin’s intrinsic strain effect. The degradation beyond the reversible strain limit was attributed to a fracture of the superconducting layer. As a whole, the present study made clear quantitatively the tensile strain behavior of critical currents and proposed a reasonable definition for the reversible strain limit.