Creep Mechanism of Polycrystalline Yttrium Aluminum Garnet

Abstract

The high‐temperature deformation behavior of a fine‐grained polycrystalline yttrium aluminum garnet (YAG) was studied in the temperature range of 1400° to 1610°C using constant strain rate compression tests under strain rates ranging from 10 −5 /s to 10 −3 /s. The stress exponent of the creep rate, the activation energy in comparison with that for single‐crystal YAG, and the grain size dependence suggest that Nabarro–Herring creep rate limited by the bulk diffusion of one of the cations (Y or Al) is the operative mechanism.