A unified model is developed to analyze the continuous evolution of heterogeneous precipitation in aluminum alloys, spanning from nucleation to coarsening. The model explicitly accounts for nucleation at various potential sites such as grain boundaries (faces, edges, and corners), dislocations, and sub-grains. By considering the competition among embryos for solute during early growth, the total number of surviving nuclei is determined during the nucleation stage. Precipitate evolution is then evaluated through a continuous formulation of the master equation that incorporates both interfacial mobility and interfacial energy. This approach offers a comprehensive cluster dynamic framework for understanding and simulating the kinetic processes governing heterogeneous precipitation behavior. Application of the model to heterogeneous θ′-Al₂Cu precipitation in a binary Al–Cu system demonstrates the critical role of nucleation mechanisms and the origin of nuclei in achieving accurate predictions of precipitate evolution. The results further demonstrate that interfacial mobility strongly governs precipitation kinetics, significantly influencing precipitate size distributions and their temporal evolution during aging.
Jamali et al. (Wed,) studied this question.