Effect of periodic image interactions on kink pair activation of screw dislocation

• DOI: 10.1016/j.commatsci.2023.112369
• Publication Date: 2023-07-15T16:30:26Z
• Authors: Fei Shuang; Rigelesaiyin Ji; Liming Xiong; Wei Gao
• Keywords: Peierls stress; Periodic boundary conditions; Line (geometry)

Periodic boundary condition along a dislocation line is commonly used in computing activation barriers or formation energies of kink pair of screw dislocation in BCC metals. Although the effect of periodic image interactions on the computation results is obvious, there had been no comprehensive analysis on such effect. In this work, we quantify it through combined nudged elastic band (NEB) simulations and theoretical analysis based on dislocation mechanics. The NEB calculation result demonstrates a non-negligible size dependence on the activation barrier at zero and low stresses. The theoretical analysis offers a practical approach to quantify such size effect without the need of time-consuming NEB simulations. Notably, a simple relationship between kink activation barrier and dislocation line length is derived at zero stress, offering a new approach to compute kink pair formation energy based on NEB simulation results.<br/>Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.<br/>Team Poulumi Dey<br/>