Molecular dynamics simulation of the grain boundary sliding behaviour for Al Σ5 (210)

In this study the grain boundary sliding (GBS) behaviour driven by a constant shear rate or shear force was investigated for the Al Sigma 5 (210) grain boundary at 500-750 K. It is found that regardless of the type of driving force, the bi-crystal system tended to resist the force applied by GB rotation which resulted from the surface strain, GB migration, or GB coupled motion. The GB generally rotated to the (100) plane of the left grain by 26.57 degrees and in particular cases to the (010) plane of the right grain by 63.43 degrees. Under a constant shear force the GBS only experienced a certain GB rotation and slid away when a threshold stress was reached. This threshold stress decreased with the increase of temperature, but under a constant shear rate, the GBS was strongly related to the temperatures. At 500 K, the GBS experienced a relatively complicated process involving GB migration, coupled motion, grain rotation, released defects and the beginning of cracks, while at 750 K, GB rotation dominated GBS behaviour. (C) 2013 Elsevier B.V. All rights reserved.