Stress-strain characteristics and fracture surface morphology of (Sm,Gd)-Ba-Cu-O bulk superconductor

The tensile strength in a- or b-direction of melt-processed (Sm,Gd)-Ba-Cu-O single grain bulk superconductor without Ag addition have been investigated by using specimens cut from the bulk sample. The maximum value of tensile strength of the specimens annealed in pure O₂ atmosphere was higher than that of the Y- and Sm-Ba-Cu-O bulk superconductor without Ag addition previously reported. The tensile strength was relatively higher in the central region of the bulk. Fracture surface of the specimens with relatively high tensile strength included the large region with the steps perpendicular to the c-direction. Flow markings showing crack propagation were found on the region without steps on the fracture surfaces.