Place: DPG Spring Meeting 2013, Regensburg, Germany
The grain boundary free energy and mobility are important quantities in describing grain growth and thus the evolution of the microstructure in polycrystalline materials. In this study we use transition path sampling (TPS) to investigate the transformation of one particular grain orientation into another via the migration of a grain boundary within a Lennard-Jones system. The trajectories describe the entire transition including the initial formation of the grain boundary. By reweighting the path ensemble it is then possible to extract the free energy as a function of any arbitrary order parameter and thus determine the grain boundary free energy at various temperatures. Since all trajectories in the path ensemble are true dynamical trajectories of the system the path ensemble also contains information about the mobility as well as the migration mechanism of the grain boundary.