LAUSR

ABSTRACT The inherent brittleness and low sustainability of YBa2Cu3O7–x (YBCO) bulk superconductor seriously impede its wide applications. It is a great challenge to achieve toughening of this material and maintain its invariable superconductivity at the same time. Here, we fabricate bulk YBCO composite superconductor with a density of 2.15 g cm−3, which consists of interlocking dual network construction and shows high toughness and durability. The results show that its unit normalized fracture energy at 77 K reaches 638.6 kN m−2, which is ∼14.8 times that of YBCO bulk prepared by the top-seeded melt textured growth (TSMTG) method. Its critical current shows no degradation during the toughening process. Moreover, after 10 000 cycles, the sample does not fracture with the decay of critical current at 4 K of 14.6% whereas the TSMTG sample fractures only after 25 cycles.