HIGH-TEMPERATURE DEFORMATION OF POLYCRYSTALLINE TL2BA2CACU2OX

High-temperature deformation of approximate to 75-80% dense polycrysta lline Tl2Ba2CaCu2Ox (Tl-2212) was studied at approximate to 90% of its melting temperature. For strain rates t of 5 x 10(-6)-2 x 10(-5) s(-1 ), deformation occurred by diffusional flow. The creep rate could be d escribed by an Arrhenius relationship: (epsilon) over dot = A sigma(1. 3+/-0.2)pO(2)(-1/(2.2+/-0.5)) exp(-(566+/-150 kJ/mole)/RT). where A is a constant, a is stress, pO(2) is oxygen partial pressure, R is the g as constant, and Tis absolute temperature. The activation energy was a scribed to diffusion of one of the cations along short-circuiting path s such as grain boundaries, stacking faults, or dislocation cores. The pO(2) dependence of (epsilon) over dot was similar to that obtained p reviously for YBa2Cu3Ox. Published by Elsevier Science Ltd.