Fractographic observations on Sm-Ba-Cu-O bulk superconductors fractured by tensile tests

The fracture surface morphology of top-seeded melt-grown SmBa₂Cu₃O_x bulk superconductors after tensile tests in 〈100〉 direction at room temperature was observed using SEM. There were voids with and without Ag particles of diameters ranging from 80 to <10 μm on the fracture surface of high density sample, while the size was 300 μm at the largest on the low density sample. Ag particles of 10 to 20 μm had the matching mate on the other side of the fracture surface. In the high density samples, the propagation of the crack was easily traced through the flow markings with steps on the fracture surface, while it was difficult to trace in low density samples.