Time: 01:40 p.m.
Place: Materials Day 2013, Ruhr-Universität Bochum, Bochum, Germany
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 ofinterest will go far beyond what can be reached with regular moleculardynamics simulations.
In this talk I will discuss two examples from the class of solid-solid and solid-liquid phase transformations. The atomistic mechanisms during solid-solid phase transformations in bulk systems might involve massive structural rearrangements including concerted multi-atom processes. Here, we employ an adaptive kinetic Monte Carlo approach to investigate such processes at the interface between cubic and topologically close-packed phases in transition metals.
The second example focusses on how solid-liquid interface properties can be extracted from atomistic simulations. Here, the interface mobility is rather high, but to follow the full transformation from the solid to the liquid phase or vice versa a high nucleation barrier has to be overcome. 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.