The elimination of grains and grain boundaries in grain growth

The topological changes that occur during coarsening of 2D and 3D cellular structures, such as polycrystals, are investigated. Particular attention is given to the elimination of grain boundaries and grains with more than the minimum number of topological elements. A thermodynamic criterion is introduced to find out which topological transformations are favoured, based on the evaluation of the Gibbs free energy of the initial and final configurations. In general, elimination of grains is possible only if the number of their neighbours is below a critical value, which may be affected by geometry.