High temperature plastic deformation related to grain boundary chemistry in cation-doped alumina

High temperature plastic deformation in fine-grained, polycrystalline alumina often takes place by diffusional creep or grain boundary sliding in a fairly wide stress and temperature range. Under such conditions, the high temperature creep or plastic flow behavior in alumina is sensitively affected by small amount of cation-doping, even in the dopant level of 0.1 mol% or less. The dopant effect on the plastic deformation in alumina results from a change in chemical bonding state at the grain boundaries due to the dopant cations’ segregation along the grain boundaries. Grain boundary chemistry dominantly affects matter transport phenomena in the grain boundaries and the high temperature mechanical property in alumina.