Grain boundary structures and sliding of alumina bicrystals

Abstract

Atomic structures and high-temperature mechanical properties of [0001] symmetric tilt grain boundaries in alumina (Al2O3) bicrystals were studied by high-resolution electron microscopy (HRTEM) and compressive creep tests. Al2O3 bicrystals were obtained by a diffusion-bonding technique, and it was found from HRTEM observations that their grain boundaries showed characteristic core structures, depending on their misorientations and grain-boundary planes. From creep tests for Al2O3 bicrystals, grain-boundary sliding rates were also found to depend on grain boundary characters, which is likely related to the core structures at grain boundaries.