MD Simulation on Evolution of Micro Structure and Failure Mechanism around Interactional Voids in Pure Al

Abstract

Experiments have shown that initial voids may exist in the manufacturing processes of pure aluminum, which adversely affect its mechanical properties. In this study, the process of plastic deformation around voids in pure aluminum was examined at atomic scale through molecular dynamics (MD) simulation. The Modified Embedded Atom Method (MEAM) was employed to characterize the atomic interactions in the pure aluminum with two voids. The calculation results revealed that the interaction of two voids endures three phases when the interval of the voids is increased: void coalescence, void coactions followed by the formation of a stress shield zone, and interaction vanishing. The critical parameters of the interval for the three phases were defined as well in this work. It was observed that crack initiated and further propagated near the voids along the slip systems of FCC crystal, which eventually caused structural failure. Meanwhile, the evolution of micro structure in the crack propagation process was investigated by means of Common Neighbor Analysis (CNA). The results showed that the phase transformation occurred near the voids during loading process.