PHASE-FIELD SIMULATION OF TWO-PHASE GRAIN GROWTH WITH HARD PARTICLES

Grain growth, due to its importance in controlling the physical properties of a wide variety of materials, has been extensively investigated. Second-phase particles have the capacity to "pin" grain boundaries and therefore affect the grain growth behavior of polycrystalline materials profoundly. They reduce the mobility of grain boundaries and eventually, when a critical grain size is reached, arrest grain growth. Based on a diffuse-interface description, a computer simulation model for studying the microstructural evolution in two-phase solid has been developed. For a grain system with hard particles, the kinetics of two-phase grain growth with the third hard particles was investigated by phase field model with a continuum diffuse-interface field. A polycrystalline microstructure of temporal and spatial evolution of the three-phase-solid system was obtained by solving three kinetics equations. It is found that the pinning effect is enhanced with the increase of the size and the volume fraction of third-phase particles. The greater the volume fraction and size of third-phase particles are, the smaller the limited sizes of grain growth are. If the volume fraction of third-phase particle maintains a constant and the size of third-phase particles is smaller, then the pinning effect of third-phase particles is stronger. When third particles with two different sizes under the same volume fraction are introduced in the system of grain growth, the pinning effect of the particles is the best. The power growth law, grain morphology, critical grain size, grain growth dynamics and topology structure of two-phase polycrystalline materials simulated by phase-field model are in well accordance with the experimental results and theoretical results of other simulations.