Influence of orientation on crack propagation of aluminum by molecular dynamics

The crack growth behavior of single crystal aluminum is investigated under tensile test at room temperature by molecular dynamics simulations. Three crack models are selected, which are [001](010) crack, ((1) over bar 10)[110] crack and [11(2) over bar](111) crack. The results present that the mechanical properties and deformation mechanisms are significantly influenced by the orientation of initial crack. The [(1) over bar 10] (110) crack has the maximum yield strength, the [11(2) over bar] (111) crack has the maximum elastic modulus. The [001](010) crack propagates in the form of micro-cracks and shows ductility fracture, and the main deformation mechanisms are blunting and slip bands at crack tip. The ((1) over bar 10)[110] crack evolves into a void with the loading increasing, presents ductile extension, and the slip bands divide the crystal structure into mesh region. For (111) [11(2) over bar] crack, it has very good toughness and ductility and can effectively reduce structural damage caused by crack propagation.