Effect of concurrent thermal grooving and grain growth on morphological and topological evolution of a polycrystalline thin film: Insights from a 3D phase-field study

Experiments and computer simulations of bicrystals have been extensively used to study the role of thermal grooving on grain boundary motion. Although these studies provide a fundamental understanding of the factors that affect boundary motion, they do not capture interactions between the grain boundary network and (solid-vapor) surface on the overall grain growth kinetics. To understand the complex interactions between the thermal groove and the grain boundary, we developed a three-dimensional phase-field model to simulate concurrent capillary-driven grain growth and surface diffusion-controlled thermal grooving. We systematically studied the role of film thickness and surface diffusivity on the interactions between thermal grooving and grain growth in polycrystalline films. To make outcomes statistically significant, we implement an efficient active parameter tracking algorithm that can simulate a large number of grain orientations. Our results show an increase in the degree of stagnation with the reduction in film thickness due to the modification of boundary curvature normal to the surface of the film. Large-scale simulations of polycrystalline films show the development of nonuniform groove surface profiles with varying degrees of asymmetry that correspond to steady state, decelerating, and stationary boundaries. The stagnation of grain boundaries shows dependence on groove depth and topological distribution of grains. The critical grain size for grain boundary stagnation and grain size distribution varies with film thickness. We also demonstrate, using various tailored configurations, how concomitant thermal grooving can lead to the complete arrest of grain growth.