Development of in-situ measurement method of internal strain and critical current of composite superconductors and their quantitative evaluation

本文旨在建立一种基于X射线衍射法的应变测量方法，并在实验结果的基础上建立模型，以定量评估热应变和外加应变对超导复合带材超导性能的影响。研究了残余应变的累积过程、临界电流与n值的拉/弯应变关系、外加应变下因损伤程度不同而各不相同的临界电流分布及其统计特征。临界电流和n-定量地阐明了高模量材料与复合带材的叠层对Bi 2223复合带材临界电流应变容限的影响。

The present work aimed to construct a quantitative estimation method of correlation of thermal- and externally applied strains to superconducting property of superconducting composite tape by developing in-situ strain measurement method with X ray diffraction method and modeling based on the experimental results. The residual strain accumulation process, tensile/bending strain dependence of critical current and n-value, distribution of critical current under applied strain, which is different from specimen to specimen due to the difference in extent of damage, and its statistical feature, sample length-dependence of critical current and n-value under applied strain and effect of lamination of high modulus material to composite tape on strain tolerance of critical current in Bi2223 composite tapes were quantitatively elucidated.