A multiscale approach based on molecular dynamics (MD) and kinetic Monte Carlo (kMC) methods is developed to simulate the dynamics of an ⟨a⟩ screw dislocation in α-Ti. The free energy barriers for the core dissociation transitions and Peierls barriers for dislocation glide as a function of temperature are extracted from the MD simulations (based on Machine Learning interatomic potentials and optimization); these form the input to kMC simulations. Random walk dislocation trajectories from kMC agree well with those predicted by MD. On some planes, dislocations move via a locking-unlocking mechanism. Surprisingly, some dislocations glide in directions that are not parallel with the core dissociation direction. The MD/kMC multiscale method proposed is applicable to dislocation motion in simple and complex materials (not only screw dislocations in Ti) as a function of temperature and stress state.
@article{arxiv.2306.10836,
title = {Finite-temperature screw dislocation core structures and dynamics in $\alpha$-titanium},
author = {Anwen Liu and Tongqi Wen and Jian Han and David J. Srolovitz},
journal= {arXiv preprint arXiv:2306.10836},
year = {2023}
}