Dresden 2011 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 23: Phase Transformations I

MM 23.1: Vortrag

Mittwoch, 16. März 2011, 11:00–11:15, IFW D

Junction controlled grain growth: evolution equations and grain size distributions — •Peter Streitenberger and Dana Zöllner — Institut für Experimentelle Physik, Abteilung Materialphysik, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, D-39106 Magdeburg

Normal grain growth is essentially controlled by the grain boundaries. However, the other structural elements of a 3D grain network (triple lines and quadruple points) may have likewise a strong effect on the growth kinetics but at very small grain sizes. For a systematic estimation of the influence of the energetic and kinematic properties of boundary junctions on grain growth each type of junction is assigned an own specific energy and mobility. By application of a thermodynamic variation principle a general grain evolution equation is derived.

Apart from the already known size parameters associated with finite boundary junction mobilities two further size parameters associated with non-vanishing specific energies of triple lines and quadruple points enter the calculation. Consequently, apart from linear and exponential kinetics already considered by Gottstein, Shvindlerman and others, six further types of growth kinetics can be identified at very small grain sizes. Each type of growth kinetics is characterised by a separable scaling form of the grain evolution equation from which analytical expressions of the corresponding self-similar size distribution function are derived. The obtained size distributions of triple and quadruple junction limited grain growth are clearly shifted to smaller relative sizes indicating a strong population enhancement in this range.