Computer modeling of micromorphological change by phase field models: applications to metals and ceramics

This paper presents computer simulations of micromorphological changes in various solids and a comparison between the numerical results and the corresponding experiments. More specifically three different solids and the micromorphological phenomena observed therein will be investigated: first, the precipitation and coarsening of tetragonal in cubic phase in Partially Stabilized Zirconia (PSZ), second, the coarsening and rafting phenomenon of Ni-base superalloys and, third, the phase separation and coarsening in eutectic tin/lead (SnPb) solders. Discrete Fourier transforms are used for the numerical treatment of the thermo-elastic, diffusion and order parameter problems encountered during the modeling of these phenomena. More specifically, the analysis will be based exclusively on continuum theory and starts with a numerical computation of the local stresses and strains in a representative volume element (RVE) of the solid. This information is then used in partial differential equations to study the evolution of local concentrations of the constituents as well as their state of order. Such 'extended' phase field equations allow to quantitatively determine the influence and the interaction between classical diffusion of the Fickean type, surface energies according to Cahn and Hilliard, as well as the mechanical stresses and strains that accompany or arise during coarsening and phase separation. Copyright (2000) The Australian Ceramic Society