IMPACT OF GRAIN BOUNDARY CHARACTER ON FACETING AND MIGRATION OF LOW ANGLE BOUNDARIES AND GRAIN ROTATION: EXPERIMENTS AND SIMULATIONS

摘要

The migration and faceting behavior of low angle <100> tilt and mixed grain boundaries was investigated. For measurements on high purity aluminum bicrystals an in-situ technique based on orientation contrast imaging was applied. In contrast to the pure tilt boundaries, the mixed boundaries readily assumed a curved shape and steadily moved under the capillary force. Computational analysis revealed that this behavior is due to the inclinational anisotropy of grain boundary energy, which in turn depends on boundary geometry. The shape evolution and shrinkage kinetics of cylindrical grains with different tilt and mixed boundaries were studied by molecular dynamics simulations.