Regensburg 2010 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 41: Topical Session Growth Kinetics II

MM 41.3: Vortrag

Mittwoch, 24. März 2010, 17:45–18:00, H4

Grain growth under limited junction mobility — •Dana Zöllner and Peter Streitenberger — Otto-von-Guericke-Universität Magdeburg, Institut für Experimentelle Physik, Postfach 4120, 39016 Magdeburg, Germany

Recently it has been demonstrated by experimental, theoretical and molecular dynamics simulation studies that triple lines and quadruple points of a three dimensional grain network may have finite mobilities different from the adjoining grain boundaries. Hence the kinetics of grain growth at very small grain sizes can depend also on the mobility of these boundary junctions.

We model nanocrystalline grain growth in polycrystals under the assumption that the mobility of grain boundaries is limited at small grain sizes. The standard Monte Carlo Potts model is modified by assigning each grain feature - grain boundary interface, triple line and quadruple point - its own specific mobility. For initially very small grains it can be observed that a reduction of the triple junction and quadruple point mobility leads to a change of the growth kinetics of a 3D grain network from parabolic to linear and exponential growth. These changes in the growth behaviour of the mean grain size are associated with changes in the grain size distribution. Due to the larger number of small grains the size distribution is shifted to smaller relative grain sizes. Additionally, new analytic grain size distribution functions have been calculated for the junction limited growth regimes, which are in excellent agreement with the simulation results.