Generalized-stacking-fault energy surface and dislocation properties of aluminum

We have employed the semidiscrete variational generalized Peierls-Nabarro m odel to study the dislocation properties of aluminum. The generalized-stack ing-fault (GSF) energy surface entering the model is calculated by using fi rst-principles density functional theory (DFT) and the embedded-atom method (EAM). Various core properties, including the core width, dissociation beh avior, energetics, and Peierls stress for different dislocations have been investigated. The correlation between the core energetics and the Peierls s tress with the dislocation character has been explored. Our results reveal a simple relationship between the Peierls stress and the ratio between the core width and the atomic spacing. The dependence of the core properties on the two methods for calculating the GSF energy (DFT vs EAM) has been exami ned. Although the EAM gives the general trend for various dislocation prope rties, it fails to predict the correct finer core structure, which in turn can affect the Peierls stress significantly (about one order of magnitude).