Distortion of a polycrystalline Al bar in a vice fixture: molecular dynamics analysis of grain movement and rotation

Abstract

The deformation of a nano-sized polycrystalline Al bar under the action of vice plates is studied using molecular dynamics simulation. Two grain sizes are considered, fine-grained and coarse-grained. Deformation in the fine-grained sample is mainly caused by grain-boundary processes which induce grain displacement and rotation. Deformation in the coarse-grained sample is caused by grain-boundary processes and dislocation plasticity. The sample distortion manifests itself by the center-of-mass motion of the grains. Grain rotation is responsible for surface roughening after the loading process. While the plastic deformation is caused by the loading process, grain rearrangements under load release also contribute considerably to the final sample distortion.