Critical Current of Various REBCO Tapes Under Uniaxial Strain

For high-current REBCO superconductors in high magnet fields with currents on the order of 50 kA, single coated conductors must be assembled in a cable. Under operating conditions, such cables are subjected to combined torsion, axial, and transverse loads in the tapes and tape joints. As such, the single tape performance under applied axial strain is crucial to understand cable limitations, and important for choosing an appropriate tape geometry and tape supplier. The critical current (I-c) versus applied uniaxial strain and the relative strain irreversibility limit were measured on HTS tapes produced by five manufacturers. The Ic measurements were performed at 77 K in self-field with the sample tapes soldered to the U-shaped bending spring (U-spring). It has been observed that most of the tapes perform well under applied compressive strain. The dependence of Ic on applied strain and the irreversibility limits were found to be unique for each tape. The n-values of the tapes, unlike the Ic, are less sensitive to applied strain in the reversible regime. The results of different tapes are presented and compared.