Investigation of mechanical properties of aluminum: molecular dynamics approach

Abstract

In the present study, the mechanical properties of a single crystal and nanocrystalline aluminum were investigated. The systems were deformed under uniaxial loading at atomistic level. First, the investigation was performed to predict the accuracy of various many-body interatomic potentials available on estimating the mechanical properties of single crystal aluminum. As such, results from the current simulations were compared with available experimental data from references. From the study, it was demonstrated that potentials which were parameterized for the elastic constants at room temperature showed high accuracy with the experimental data. Out of fourteen potentials tested in the current research, the Mishin et al. EAM potential predicted the most accurate mechanical properties for single crystal aluminum. Next, this potential was used to simulate uniaxial deformation for nanocrystalline aluminum. Results showed good agreement with available experimental data for nanocrystalline aluminum. The effects of various grain sizes, strain rates, and temperatures were investigated. It was observed that the stacking faults, sliding of the grain boundaries, and nucleation of atoms near grain boundaries during deformation hardened the nanocrystalline material as the grain diameter increased, which is reverse Hall-Petch relationship.