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Hier finden Sie wissenschaftliche Publikationen aus den FraunhoferInstituten. Predictive theory for the grain boundary character distribution
 Palmiere, E.J.: Recrystallization and grain growth IV. Selected, peer reviewed papers from the Fourth International Conference on Recrystallization and Grain Growth, ReX & GG 2010 : July 4  9, 2010, Sheffield, UK DurntenZurich: TTP, 2012 (Materials Science Forum 715/716) ISBN: 9783037853900 pp.279285 
 International Conference on Recrystallization and Grain Growth (ReX & GG) <4, 2010, Sheffield> 

 English 
 Conference Paper 
 Fraunhofer IGD () Fraunhofer Austria () 
 simulation; materials research; prediction 
Abstract
Mesoscale experiment and simulation permit harvesting information about both geometric features and texture in material microstructures. The grain boundary character distribution (GBCD) is an empirical distribution of the relative length (in 2D) or area (in 3D) of interface with a given lattice misorientation and grain boundary normal. During the growth process, an initially random texture distribution reaches a steady state that is strongly correlated to the interfacial energy density. In simulation, it is found that if the given energy depends only on lattice misorientation, then the steady state GBCD and the energy are related by a Boltzmann distribution. This is among the simplest nonrandom distributions, corresponding to independent trials with respect to the energy. Why does such a simple distribution arise from such a complex system?
We derive an entropy based theory which suggests that the evolution of the GBCD satisfies a FokkerPlanck Equation. Cellular structures coarsen according to a local evolution law, curvature driven growth, and are limited by space filling constraints. The interaction between the evolution law and the constraints is governed primarily by the force balance at triple junctions, the natural boundary condition associated to curvature driven growth, and determines a dissipation relation. A simplified coarsening model is introduced which is driven by the boundary conditions and reflects the network level dissipation relation of the grain growth system. It resembles an ensemble of inertiafree springmassdashpots. Critical application is made of the recent characterization of FokkerPlanck kinetics as a gradient flow for a free energy in deriving the theory. The theory predicts the results of large scale 2D simulations and is consistent with experiment.