Place: International Conference on Computational Physics, Singapore
Modelling the dynamical evolution of systems during phase transformations on the atomistic level is a particular challenging task. If the dynamics are governed by so-called rare events then the time scale of interest will go far beyond what can be reached with regular molecular dynamics simulations. The atomistic mechanisms during solid-solid phase transformations in bulk systems might involve massive structural rearrangements including concerted multi-atom processes. The properties of the interface between two structurally very different phases leads to a complex energy landscape that describes the dynamical evolution of the interfaces. Here, we employ an adaptive kinetic Monte Carlo approach to explore the energy landscape and to investigate the corresponding processes at the interface between cubic and topologically close-packed phases in transition metals.
To describe solidification processes solid-liquid interface properties are key and nowadays detailed information about these properties can be extracted from atomistic simulations. To follow the full transformation from the solid to the liquid phase or vice versa usually a high nucleation barrier needs to be overcome which again turns this into a rare event problem. Here, the dynamical trajectories connecting the solid and liquid state are investigated using transition path sampling. A proper reweighting of the path ensemble allows not only for the extraction of free energy barriers but also for the analysis of dynamical properties and transformation mechanisms.