Finite element analysis for surface diffusion-controlled shape instabilities of plate-like grains

Abstract

Based on classical theory of surface diffusion and evaporation- condensation, a finite element program is developed to simulate the unstable shape evolution of plate-like grains. The program is used to analyze thermal grooving on a polycrystalline surface and compared with a non-linear solution and finite difference analysis. It shows that the finite element method used is robust, accurate and efficient. Then, the shape evolution kinetics of the plate-like grains are simulated as a function of the thermal grooving angle θ at the grain boundary-surface junctions and the initial aspect ratio of the plate β (plate width to thickness). When θ = 0 (without internal boundary), the plate-like grain will evolve into cylinders directly. When an internal boundary exists, there is a critical thermal grooving angle θmin for given β. If θ 10, its effect can be neglected. © 2001 Elsevier Science B.V.