Effect of grain boundary energy anisotropy on grain growth in ZK60 alloy using a 3D phase-field modeling

【摘要】 A three-dimensional(3D) multiple phase field model, which takes into account the grain boundary(GB) energy anisotropy caused by texture, is established based on real grain orientations and Read–Shockley model. The model is applied to the grain growth process of polycrystalline Mg(ZK60) alloy to investigate the evolution characteristics in different systems with varying proportions of low-angle grain boundary(LAGB) caused by different texture levels. It is found that the GB energy anisotropy can cause the grain growth kinetics to change, namely, higher texture levels(also means higher LAGB proportion) result in lower kinetics, and vice versa. The simulation results also show that the topological characteristics, such as LAGB proportion and distribution of grain size, undergo different evolution characteristics in different systems, and a more serious grain size fluctuation can be caused by a higher texture level. The mechanism is mainly the slower evolution of textured grains in their accumulation area and the faster coarsening rate of non-textured grains. Therefore, weakening the texture level is an effective way for implementing a desired homogenized microstructure in ZK60 Mg alloy. The rules revealed by the simulation results should be of great significance for revealing how the GB anisotropy affects the evolution of polycrystalline during the grain growth after recrystallization and offer the ideas for processing the alloy and optimizing the microstructure.更多还原

【Abstract】 A three-dimensional(3D) multiple phase field model, which takes into account the grain boundary(GB) energy anisotropy caused by texture, is established based on real grain orientations and Read–Shockley model. The model is applied to the grain growth process of polycrystalline Mg(ZK60) alloy to investigate the evolution characteristics in different systems with varying proportions of low-angle grain boundary(LAGB) caused by different texture levels. It is found that the GB energy anisotropy can cause the grain growth kinetics to change, namely, higher texture levels(also means higher LAGB proportion) result in lower kinetics, and vice versa. The simulation results also show that the topological characteristics, such as LAGB proportion and distribution of grain size, undergo different evolution characteristics in different systems, and a more serious grain size fluctuation can be caused by a higher texture level. The mechanism is mainly the slower evolution of textured grains in their accumulation area and the faster coarsening rate of non-textured grains. Therefore, weakening the texture level is an effective way for implementing a desired homogenized microstructure in ZK60 Mg alloy. The rules revealed by the simulation results should be of great significance for revealing how the GB anisotropy affects the evolution of polycrystalline during the grain growth after recrystallization and offer the ideas for processing the alloy and optimizing the microstructure.更多还原