Molecular dynamics studies for the generation and the movement of dislocation

Abstract

In this study, molecular dynamics (MD) simulations were performed to observe the generation and gliding behaviors of a dislocation in an α-Fe plate under 2-dimensional loading. In MD simulations, the acceleration of each molecule is achieved from the potential energy and the force interacting between molecules. The integration of the motion equation by the Verlet method gives the displacement of the molecules. Initially, an α-Fe material having a regular lattice structure was modeled to consist of 800 molecules, and from among these the 10 molecules lying on one inclined line were removed from the plate. By the interaction of forces between each molecule, the plate goes to an another equilibrium state with an irregular lattice structure having an internal dislocation inside. When the plate with a dislocation is subjected to tensile or compressive loading under several temperatures and loading speeds, the dislocation glides and escapes upward or downward. As the temperature and the loading speed increase, the dislocation forms at an early stage of deformation and glides more easily.