Compressive Creep of a Fine‐Grained Poly crystal line Yttria

Compressive creep of a high-purity fine-grained polycrystalline yttria ceramic processed by hot isostatic pressing has been investigated in the 1,130--1,210 C temperature range for stresses between 6 and 92 MPa. The main creep mechanism is grain boundary diffusion controlled by an interface reaction. The most striking feature is the strong dynamic grain growth whereas static grain growth is negligible in the studied temperature domain.