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

本工作旨在通过发展X射线衍射法的现场应变测量方法和基于实验结果的建模，建立一种热应变和外加应变与超导复合带材超导性能相关性的定量估计方法。定量地阐述了Bi2223复合带材的残余应变积累过程、临界电流和n值的拉伸/弯曲应变关系、由于损伤程度的不同而不同试件在不同应变下的临界电流分布及其统计特征、临界电流和n值的样品长度依赖关系以及高模材料在复合带材上的层叠对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.