Microstructural evolution in two-phase solids: morphological stability of near-periodic particle arrangements

Microstructural evolution in binary alloys is studied numerically using a sharp interface model and boundary integral techniques together with a time stepping scheme. Two-dimensional matrix-inclusion type microstructures are considered with an isotropic interfacial energy density and cubically orthotropic elasticity, being distinct in the two phases. An assumption of local equilibrium is applied which provides the coupling of the diffusion and the elasticity problems via an interfacial jump condition. Special attention is paid to the verification of a phenomenon observed in an earlier work: energy considerations suggested the possibility of sustained inverse coarsening leading to equilibrium microstructures with large numbers of small particles. It is found that, while such stationary states exist, their domain of attraction is rather small; reduction of surface area is the dominant driving force in the process.