FeSe0.5Te0.5 coated conductor as a kind of 11-type iron-based superconductor is currently attracting much attention. Recently, the bare FeSe0.5Te0.5 coated conductor tapes were developed by Shanghai Jiao Tong university and verified their superconductivity. For the future application, the FeSe0.5Te0.5 tapes should be subjected to the high electromagnetic forces and stress-strain. In this study, the authors encapsulated the bare FeSe0.5Te0.5 coated conductor tapes with copper layers to enhance the mechanical performance. The reversible critical current performance of the bare and the copper encapsulated FeSe0.5Te0.5 tapes under uniaxial tensile strain was tested. The critical currents of two kinds of tapes were measured over a wide range of applied uniaxial tensile strain by the U-shaped bending spring, respectively. The results show the critical performance of the bare FeSe0.5Te0.5 tapes decreases linearly with respect to tensile strain. The copper encapsulated FeSe0.5Te0.5 tapes have better performance than the bare tapes, with an irreversible tensile strain limit of 0.15%. In addition, the actual irreversible tensile strain limit of the copper encapsulated FeSe0.5Te0.5 tapes reaches 0.29% after considering the influence of the cooling process.

122-type iron-based superconductors (IBS) have attracted extensive attention due to their excellent performance. The 100-m class Ba1-xKxFe2As2 (Ba-122) 7-filamentary IBS tapes were successfully fabricated in Institute of Electrical Engineering, Chinese Academy of Sciences. This study has performed the tests of the 7-filamentary Ba-122 short tape samples (Bas samples) and the 100-m class 7-filamentary Ba-122 tape samples (Ba100 samples) under various kinds of strain by the U-shaped bending spring devices. Both types of samples were still reversible even when the applied compressive strain reached -0.65%. In addition, the reversible tensile strain limit of the Bas and Ba100 samples were 0.25% and 0.28%, which increased to 0.38% and 0.41% after considering the effect of the cooling process.

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