Mechanical and critical current characteristics of high-strength BiSrCaCuO multi-filamentary tapes reinforced with thicker Ni-alloy laminations with various pre-tensions

Abstract

We investigated the stress–strain relation and the applied strain dependence of the critical current of high-strength Bi2Sr2Ca2Cu3O (Bi2223) R&D tapes reinforced by thick Ni-based alloy sheets with various pre-tensions applied during the lamination process. We confirmed that the thickening of Ni-alloy laminations is useful for enhancing Young’s modulus compared with commercial tapes ( thick laminations). decreases gradually and reversibly with applied strains and then degrades irreversibly with larger tensile and compressive strains. The reversible strain regime tends to shift toward the tensile side with larger , indicating that application of large is effective in improving the reversible tensile strain limit. The observed can be reproduced well by model considering -linear critical current density, cross-sectional strain distribution, and Weibull-type distribution of filament damage. We clarified that different irreversible degradations with large tensile and compressive strains can be understood by differences in the dimensions and number of cracks and ruptures (tensile strains) and bucklings (compressive strains).