On the role of dislocations in heavily strained YBa2Cu3O7-δ

Dense pellets of polycrystalline YBa2Cu3O7-δ have been made by shock compaction. While YBa2Cu3O7-δ is brittle at ambient conditions, the high pressure generated during the shock deformation is known to enhance its plasticity. Plastic deformation as well as fracture occurs when the shock wave passes through the initially loose powder, and multiple defects are expected to be generated. The paper reports on the interaction of dislocations with twin boundaries, and their role in the cleavage behaviour. The observations are performed on shock-loaded samples, compacted at E/M ratios ranging from 0.8 to 2.3. The microstructure of shock-compacted samples is compared to that of the initial, non-compacted powders. Apart from the well established <100>{100} glide system, the role of the novel [110](11¯0) and [010](100) glide systems is studied. All glide systems are found to interact with the ferroelastic domains of the material, each in a different way.