Dislocation modelling in Ti₂AlN MAX phase based on the Peierls–Nabarro model

Abstract

In this study, we determined the core structure and the Peierls stress of dislocations in Ti₂AlN MAX phase. We use a generalized Peierls–Nabarro model, called Peierls–Nabarro–Galerkin (PNG), coupled with first principles calculations of generalized stacking fault (GSF). The GSF calculations show that dislocation glide in the basal plane will occur preferentially between M (here Ti) and A (here Al) planes. Additionally, the results of PNG calculations demonstrate that whatever the dislocation character, dislocations are dissociated in the basal plane, with a dissociation distance below the experimental resolution of transmission electron microscopy observations. Finally, the Peierls stress calculations show that the edge and screw characters are the easiest characters to glide in the basal plane.

Keywords:

• MAX phase
• dislocations
• Peierls–Nabarro model

Acknowledgements

The authors thank Christophe Denoual for helpful discussions and support in the PNG calculations. Computational resources have been provided by the CRI-Université de Lille 1.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the European Research Council under the Seventh Framework Programme (FP7), ERC [grant number 290424] – Rheoman.