Numerical simulation of the effects of temperature perturbation on dendritic growth

ABSTRACT Dendrite morphology and size significantly affect the microstructural uniformity of castings and ingots. Various approaches can be used to restrict dendritic growth; however, the effects of local and global temperature perturbations on dendritic growth and their underlying mechanisms remain unclear. In this study, a coupled cellular automaton–lattice Boltzmann model (CA–LBM) is employed to investigate dendritic growth in a Cu–10 wt.% Sn alloy. Strategies for controlling dendritic growth through global temperature perturbation and local temperature perturbation at the solidification front are proposed, and the effects of these two perturbation modes are systematically compared. The results indicate that, during the initial stage of local temperature perturbation, thermal undercooling is dominant and briefly accelerates dendrite tip growth. Subsequently, solute enrichment caused by accelerated solidification gradually offsets the thermal driving force, reducing the effective undercooling to negative values and ultimately arresting the growth of secondary dendrite arms. In the case of multi-point local temperature perturbation, the overlap of solute-enriched regions further extends the spatial range of dendritic growth suppression. Increasing either the magnitude or the radius of the perturbation enhances this effect. In contrast, global temperature perturbation primarily increases the overall solidification driving force, thereby promoting overall dendritic growth. This study elucidates the competition between thermal and solute effects under temperature perturbations applied over different spatial ranges and provides a theoretical basis for the control of solidification microstructures.