Atomistic modeling of the crack–void interaction in α-Fe

Abstract

The analysis of the crack–void interaction at the nanoscale in α-Fe using molecular statics (MS) and molecular dynamics (MD) in the framework of the embedded atom method (EAM) potential is presented. To this end, following three crack–void specimens are considered: (i) void positioned at a varying distance normal to the crack tip, (ii) void inserted at a varying distance along the initial crack direction in front of the crack tip, and (iii) void placed at a varying distance in the emission direction of the dislocations after the dislocation nucleation. A parametric study involving the crack–void specimen, the strain rate, and the temperature is performed and presented. Depending on different specimens, elastic shielding or anti-shielding on the crack growth is observed as a function of the temperature and strain rate. The increase of the temperature results in the decrease of the dislocation nucleation stress. At a temperature of 0K, the simulation results reveal that the crack growth rate is independent to the void location with respect to the crack tip. At a temperature of 300K, when the crack–void distance is d=5a (a being the lattice parameter), the initiation of the crack growth occurs earlier than that of the same specimen at 0K and the crack growth is blunted after the deflection. When increasing the crack–void distance, the crack growth rate is independent of the temperature.