Atomistic simulation of dislocation interactions in a model crystal subjected to shear

• Published in: Molecular simulation 2005-12, Vol.31 (14-15), p.1043-1049
• Main Authors: Popova, M., Shen, Y.-L., Khraishi, T.A.
• Format: Article
• Language: English
• Subjects: Atomistic simulation; Crystal; Dislocation; Nano-scale plasticity
• ISSN: 0892-7022; 1029-0435
• DOI: 10.1080/08927020500349999

The interaction of edge dislocations in a two-dimensional (2D) model crystal subjected to "simple shear" is studied using molecular statics simulations. An initial point defect is introduced in the model to trigger the dislocation activities in a controlled manner. We consider dislocations gliding towards one another on parallel slip planes separated by various distances. The overall load-displacement response of the crystal is obtained from the simulations, which can be correlated with the nano-scale atomistic mechanisms. Although the crystal is inherently anisotropic, the incipient dislocation plasticity is such that slip is parallel to the primary shear direction as clearly demonstrated in this work. It is also illustrated that dislocation annihilation, as well as dislocation encounter which leaves behind a point defect, can be unambiguously modeled. Throughout the deformation history, more dislocations capable of gliding in the crystal tend to generate a weaker mechanical response and more pronounced plasticity. The present study also offers mechanistic insight into experimentally observed small-scale crystal plasticity.