Atomistic Simulations of Dislocation-Void Interactions using Green's Function Boundary Relaxation

摘要

A Green's function technique is developed for the relaxation of simulation cell boundaries in the modelling of dislocation interactions using molecular dynamics. This method allows the replacement of fixed or periodical boundary conditions with flexible boundary conditions, thus minimizing the artificial effects due to images forces introduced by the fixed boundary condition, or the periodic repetition of simulation cells. The effectiveness of the Green's function in the removal of the fixed boundary image forces is first checked in the atomistic simulation involving the glide of the a/2< 110> dislocation in bcc tungsten. This method is then applied to study the reaction of an edge dislocation with voids in tungsten. The simulation results are compared with predictions from the continuum model.