STABILITY, MICROSTRUCTURAL EVOLUTION, GRAIN-GROWTH, AND COARSENING IN A 2-DIMENSIONAL 2-PHASE MICROSTRUCTURE

The stability of certain microstructural features and how this affects grain growth and coarsening in a two-dimensional polycrystalline two-phase material with isotropic energies for the two grain boundaries and the interphase interface is examined using classical concepts. A catalog of stable microstructural features depends on surface-energy ratios; it is shown to include a four-grain junction that is stable for a range of surface-energy ratios, and, for a given set of ratios, is stable over a range of angles. Three-grain junctions and grain boundaries had been known to have a limited range of stability with respect to being "wet" by the other phase. Inferences about grain growth, coarsening, and evolving morphology are obtained from the integrated curvature of the bounding surface of a grain, which depends on the number and phase of neighboring grains, as well as the order of their arrangement. Under some conditions, a dispersion of second phase grains grain boundaries will tend to a uniform size; this second phase resists coarsening.