Molecular dynamics simulations of crack growth behavior in Al in the presence of vacancies

Abstract Fracture properties of a material are strongly influenced by the presence of defects. In view of this, molecular dynamics simulations were performed within the framework of embedded atom method to investigate the crack tip behavior under mode I loading in FCC Al with and without defects. Defects consisting of a random distribution of vacancies were introduced in the precracked matrix. The results reveal a significant change in the fracture behavior of Al with defects. The interactions between the crack tip and vacancies were found to modify the stress concentrations at the crack tip. Increase in vacancy content lead to increased crack tip blunting and reduced crack propagation speeds as compared to the vacancy-free material, thereby toughening the material to fracture. The significance of such studies towards gaining deeper insights into the fracture behavior at higher scales is highlighted.