Phase-field modeling of nucleation in solid-state phase transformations

Nucleation is a critically important process as the rate of nucleation determines the number density of new phase particles and thus microstructures of a material during phase transformations. Predicting and controlling nucleation rates in solids is one of the grand challenges in materials science because the spatial scale involved in nucleation is at the atomic/nanoscale, the rate of nucleation process is extremely temperature sensitive, and the morphology of a critical nucleus can be highly nonspherical and complex. In this article, we briefly review the recent advances in modeling and predicting nucleation during solid-phase transformations based on the diffuse-interface or nonclassical description of critical nucleus profiles. The focus is on predicting the critical nucleus morphology and nucleation free energy barrier under the influence of anisotropic interfacial energy and elastic interactions. Incorporation of nucleation events in phase-field modeling of solid-to-solid phase transformations and microstructure evolution is also discussed.