Regensburg 2002 – wissenschaftliches Programm

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M: Metallphysik

M VII: HV VII

M VII.1: Hauptvortrag

Freitag, 15. März 2002, 10:45–11:15, H16

Probing the mysteries of grain growth by means of phase-field simulation — •Carl Krill — FR 7.3 Technische Physik, Universität des Saarlandes, Postfach 151150, Geb. 43B, D-66041 Saarbrücken

At first glance, the phenomenon of grain growth in a polycrystalline material appears to be quite simple: at elevated temperature, bigger grains grow at the expense of their smaller neighbors in order to reduce the total grain-boundary area, because this lowers the overall free energy. Upon closer inspection, the true complexity of this transformation becomes apparent, for it involves constant competition between the establishment of local equilibrium in the grain-boundary network and the topological requirement that the ensemble of grains fill space. Many of the mysteries uncovered in more than 50 years of experimental and theoretical investigation into this phenomenon remain unsolved, perhaps explaining why grain growth has long been a popular topic in computational materials science. Nevertheless, only recently has it become feasible to extend simulations of two-dimensional grain growth—which has no direct experimental counterpart—to 3D, where computational results can be compared to a wealth of data. We have performed the first large-scale simulations of 3-D grain growth using the phase-field model, which is arguably one of the most versatile and mature methods for simulating coarsening phenomena. In a novel application of the phase-field algorithm, we employ it to extract quantitative topological parameters from tomographic scans of the microstructure of a polycrystalline solid. This information can be used to check the validity of the simulations and improve analytic models for grain growth.