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

The fracture surface morphology of top-seeded melt-grown SmBa2Cu3Ox bulk su perconductors after tensile tests in < 100 > direction at room temperature was observed using SEM. There were voids with and without Ag particles of d iameters ranging from 80 to < 10 mum on the fracture surface of high densit y sample, while the size was 300 mum at the largest on the low density samp le. Ag particles of 10 to 20 mum 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 fractur e surface, while it was difficult to trace in low density samples. (C) 2001 Elsevier Science B.V. All rights reserved.