Plasticity of TlBa₂Ca₂Cu₃Ox

Constant-strain-rate compression tests have been performed on polycrystalline TlBa 2 Ca 2 Cu 3 O x superconductors (73-86% of theoretical density) for the first time. The tests were performed in air at temperatures of 750-850 degrees C. Apparent steady-state stresses between 1 and 300 MPa were achieved for initial strain rates of 2*10 -6 to 4*10 -5 s -1 . Deformation was probably controlled by viscous flow at the highest temperatures, but was dominated by dislocations at lower temperatures.