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MM: Fachverband Metall- und Materialphysik

MM 11: Growth

MM 11.2: Vortrag

Montag, 23. März 2009, 15:00–15:15, IFW D

Potts model simulation of triple junction limited grain growth — •Dana Zöllner and Peter Streitenberger — Institut für Experimentelle Physik, Abteilung Materialphysik, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, D-39106 Magdeburg

The size effect observed for nanocrystalline grain growth can be attributed to a limited grain boundary junction mobility yielding a junction drag.

Two different approaches are considered in the Monte Carlo Potts model: for one an effective mobility can be introduced, which is reduced by the triple junction distance and secondly each grain feature (grain boundary, triple line and quadruple points) can be assigned an own mobility. These changes in the mobility can be implemented in the Potts model through the transition probability, which calculates the attempted orientation change.

Some results of these modified Potts model simulations will be presented especially regarding the temporal development of the mean grain size and the grain size distribution. It will be shown that for the 2D case for initially very small grains a linear grain growth kinetics is observed followed by a transient state, which in later stages becomes parabolic. Furthermore, in the linear growth regime a coarsening state is reached, where the grain size distributions are shifted to smaller relative grain sizes. The coincidence of the scaled distributions implies the existence of a temporarily universal grain size distribution, which is in agreement with theoretical results based on a grain size dependent boundary mobility.