High‐Temperature Creep Behavior of Polycrystalline SrZrO ₃

Abstract

The high‐temperature creep behavior of sintered polycrystalline SrZrO 3 containing 1.35 wt% Fe 2 O 3 was investigated as a function of temperature, stress, grain size, and strain level over the ranges 1160° to 1275°C, 780 to 3110 psi, 0.45 to 2.04 μm, and 0.0014 to 0.014, respectively. A constant‐load 4‐point (pure bending) method was used to load the specimens. The creep rate is time‐dependent, decreasing exponentially with strain, i.e. , where the decay constant (β=118, measured at the 1560 psi stress level over the strain range 0.0014 to 0.014) is independent of temperature and grain size. No significant grain growth occurred during creep. The activation energy of 169±10 kcal/mol obtained for creep is relatively independent of temperature, stress, grain size, and strain level over the ranges investigated. The creep rate is directly proportional to the cube of the stress and the reciprocal of the grain size; this result is consistent with nonviscous creep theories based on dislocation generation and climb as the rate‐controlling deformation mechanism.