合金凝固过程元胞自动机模型及模拟方法的发展

DEVELOPMENT OF CELLULAR AUTOMATON MODELS AND SIMULATION METHODS FOR SOLIDIFICATION OF ALLOYS

元胞自动机(CA)是一种高效且物理意义明确的模拟方法,能够较准确地模拟合金的凝固组织演变过程.本文简述了合金凝固过程CA模拟方法的基本原理,综述了合金凝固组织演变CA模型的发展历程,分析了现存的CA模型的特点,展望了合金凝固CA模型的未来发展方向.

Dendritic structure is the most frequently observed solidification microstructure of alloys. It has a dominant effect on the mechanical properties of alloys. The formation of the dendritic microstructure has attracted extensive attentions. It has been demonstrated that numerical simulation is a powerful tool for studying the microstructure formation during the solidification of alloys. Various models, such as the front-tracking（FT） model, the phase-field（PF） model and the cellular automaton（CA） model have been proposed to simulate the formation process of dendrite. Compared with other methods, CA is an effective numerical simulation method with high calculation efficiency and clear physical meaning. It is more suitable to be applied to simulate the formation kinetics of the dendritic microstructure of alloys. It has been widely applied in the investigation of the solidification of alloys.This paper makes a detailed introduction to the common process of CA modeling and simulation, the constructing method of CA model and the calculation method for some key parameters such as nucleation rate of nuclei, growth velocity of dendrite, etc. A review of the development of the CA models for the solidification of alloys is carried out. The features and applications of the existing CA models are critically assessed. The applications of the CA models in the investigations of the practical solidification process are summarized. The problems to be solved and the future development of CA models are also pointed out.