2 research outputs found
Phase-field modeling of eutectic structures on the nanoscale: the effect of anisotropy
A simple phase-field model is used to address anisotropic eutectic freezing on the nanoscale in two (2D) and three dimensions (3D). Comparing parameter-free simulations with experiments, it is demonstrated that the employed model can be made quantitative for Ag-Cu. Next, we explore the effect of material properties, and the conditions of freezing on the eutectic pattern. We find that the anisotropies of kinetic coefficient and the interfacial free energies (solid-liquid and solid-solid), the crystal misorientation relative to pulling, the lateral temperature gradient, play essential roles in determining the eutectic pattern. Finally, we explore eutectic morphologies, which form when one of the solid phases are faceted, and investigate cases, in which the kinetic anisotropy for the two solid phases are drastically different
Phase-field modeling of polycrystalline solidification, from needle crystals to spherulites: a review
Advances in the orientation-field-based phase-field (PF) models made in the past are reviewed.
The models applied incorporate homogeneous and heterogeneous nucleation of growth centers
and several mechanisms to form new grains at the perimeter of growing crystals, a phenomenon
termed growth front nucleation. Examples for PF modeling of such complex polycrystalline
structures are shown as impinging symmetric dendrites, polycrystalline growth forms (ranging
from disordered dendrites to spherulitic patterns), and various eutectic structures, including
spiraling two-phase dendrites. Simulations exploring possible control of solidification patterns
in thin films via external fields, confined geometry, particle additives, scratching/piercing the
films, etc. are also displayed. Advantages, problems, and possible solutions associated with
quantitative PF simulations are discussed briefly