Core structure and Peierls stress of the 90° dislocation and the 60° dislocation in aluminum investigated by the fully discrete Peierls model

Abstract

The core structure, Peierls stress and core energy, etc. are comprehensively investigated for the 90° dislocation and the 60° dislocation in metal aluminum using the fully discrete Peierls model, and in particular thermal effects are included for temperature range 0 ≤ T ≤ 900 K. For the 90° dislocation, the core clearly dissociates into two partial dislocations with the separating distance D ∼ 12 Å, and the Peierls stress is very small σ p < 1 kPa. The nearly vanishing Peierls stress results from the large characteristic width and a small step length of the 90° dislocation. The 60° dislocation dissociates into 30° and 90° partial dislocations with the separating distance D ∼ 11 Å. The Peierls stress of the 60° dislocation grows up from 1 MPa to 2 MPa as the temperature increases from 0 K to 900 K. Temperature influence on the core structures is weak for both the 90° dislocation and the 60° dislocation. The core structures theoretically predicted at T = 0 K are also confirmed by the first principle simulations.