Tensile stress effects on critical current densities of coated conductors

Tensile stress dependent critical current densities (J(c)) of two types of coated conductors, which were fabricated on a pure Ni tape and a NiCr (13 a tomic %) tape respectively, were measured at 77 K, Until the stress reached certain values (K-c), the J(c) of each sample was constant, it then began to decrease as the stress was increased further. The K-c for tapes of Ni an d NiCr were similar to 100 MPa and similar to 270 MPa respectively, which m eans K-c was enhanced almost three times for the sample fabricated on the N iCr. According to the detailed changes of voltage signals for applied curre nts under various stresses, the degradation process of each sample could be divided into four different regimes.