The temperature-dependent dislocation properties of aluminum from the improved Peierls–Nabarro model and first-principles

Abstract

Based on the improved Peierls–Nabarro model in which the discreteness effects of lattice are taken into account, we propose a theoretical study on the temperature-dependent dislocation properties of dissociated edge dislocation in aluminium. In order to construct a dislocation equation involving the effects of temperature, we employ a first-principles quasi-static approach in which the lattice geometry, elastic modulus and generalized stacking fault energy (SFE) at finite temperature are calculated from the density functional theory and density functional perturbation theory in combination with the quasiharmonic approximation. A semi-analytical and semi-numerical method is introduced to solve the dislocation equations. The disregistry profile of dislocation core, dissociation behaviour and the dislocation energy including the elastic stain energy and misfit energy as a function of temperature have been investigated. At  K, our calculated results agree well with the previous theoretical and experimental values. The separation distance between two Shockley partials slightly decreases with temperature, and the results have a good agreement with the ratio between the unstable and intrinsic SFE. Moreover, the dislocation energy increases with increasing temperature, indicating that the dislocation become unstable with increasing temperature.

Keywords:

• Aluminium
• dislocation
• finite temperature
• Peierls–Nabarro model
• first-principles

Notes

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work is supported by the National Science Foundation of China [grant number 11304403] and Project no. 106112015CDJXY300006 supported by the Fundamental Research Funds for the Central Universities of China.