Mechanical characterization of top-seeded melt-textured YBa2Cu3O7-delta single crystal

The development of high J(c) superconductors for high magnetic field applications has identified the limiting problem of mechanical stability of the superconductor under high applied magnetic field. The flaw, crack and pore distribution in unannealed, annealed and avalanched, top-seeded, melt-textured YBCO disks were characterized. Flexural strength and fracture toughness of these three conditions provided sufficient data for an estimation of critical flaw size. The fracture surface and crack path were also observed by SEM methods to identify the growth character of cracks.