Relation of the strength distribution of Nb3Sn to the critical current of a pre-stressed multifilamentary composite superconductor
Relation of the strength distribution of Nb3Sn to the critical current of a pre-stressed multifilamentary composite superconductor
复制标题
Nb3Sn强度分布与预应力多丝复合超导体临界电流的关系
DOI：
10.1088/0953-2048/8/12/002
复制
发表时间：
1995
影响因子：
3.6
通讯作者：
K. Watanabe
中科院分区：
文献类型：
--
作者：
Shojiro Ochiai;S. Nishino;M. Hojo;K. Watanabe
通过分析室温预应力处理引起的4.2K超导临界电流的变化，用双参数威布尔分布函数估算了973 K热处理8.6（样品A）、43（样品B）和260 ks（样品C）的Nb_3Sn复合线材的抗拉强度分布。Weibull分布的形状参数分别为7.2、12和14，对于目前长度为25 mm的样品A、B和C，Nb 3Sn的平均强度分别为1.3、1.0和0.79 GPa。这意味着，长度为25 mm的样品的强度的分散性以及平均强度随着热处理时间的增加而减小。尝试预测的预应力短试样的临界电流的数据的长度依赖性。当试样从25 mm延长到300 m时，Nb_3Sn（对于所有Nb_3Sn输运电流）不断裂的允许预应力降低了20-30%，而Nb_3Sn的平均强度降低了50- 70%。
From an analysis of the change in the superconducting critical current at 4.2 K caused by pre-stressing treatment at room temperature, the distribution of tensile strength of Nb3Sn in multifilamentary bronze-processed composite wires heat-treated at 973 K for 8.6 (sample A), 43 (B) and 260 ks (C) is estimated using the two-parameter Weibull distribution function. The shape parameters of the Weibull distribution are 7.2, 12 and 14, and the average strengths of the Nb3Sn are 1.3, 1.0 and 0.79 GPa for samples A, B and C respectively for the present specimen length of 25 mm. This means that the scatter of strengths and also the average strength for specimens of length 25 mm decrease with increasing heat-treatment time. An attempt to predict the length dependence of the critical current of pre-stressed specimens from the data for short specimens is presented. It seems that the permissible pre-stress below which there is no breakage of Nb3Sn (for all Nb3Sn transport currents) is reduced by 20-30% when the specimen is lengthened from 25 mm to 300 m, while the average strength of Nb3Sn is reduced by 50-70%.