Stress/strain dependence of critical current in Cu-Ag externally reinforced Ag-Zr/Bi-2212 superconducting tapes

The effects of external reinforcement on the mechanical property and the ax ial tensile stress/strain dependence of the critical current I-c in Bi(2212 ) superconducting tapes were evaluated at a temperature of 4.2 K and a magn etic field of 14 T. The monocore and 19-core superconducting tapes with thr ee kinds of sheath-Ag, Ag-Zr and Ag-Zr/Ag double layer-were incorporated wi th a reinforcing Cu-Ag tape. As a result of this reinforcement, the 0.2% pr oof stress of superconducting tapes increased markedly without significant degradation of the I-c. The tolerance limit in strain for I-c degradation i n the tapes was slightly improved and those of stress were markedly improve d. The improvement in the tolerance limit in strain or stress for the degra dation was more evident in the tapes with the Ag-Zr sheath, compared with t hose with a pure Ag sheath. (C) 1999 Cryogenic Association of Japan. Publis hed by Elsevier Science Ltd. All rights reserved.