一种改进的三维元胞自动机模拟铝合金凝固
Simulation on Solidification of Aluminum Alloy Based on Modified 3-D Model
许 林1， 郭洪民2
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作者单位：1. 江西蓝天学院 新能源与材料工程系, 江西 南昌 330098； 2. 南昌大学 材料科学与工程学院, 江西 南昌 330031
中文关键字：元胞自动机； 数值模拟； 凝固过程
英文关键字：cellular automaton; numerical simulation; solidification
中文摘要：以元胞自动机模型为基础，基于晶粒形核和生长的物理过程，建立了铝合金凝固过程演化的三维元胞自动机模型。枝晶尖端生长速度与局部过冷度的关系采用KGT模型，温度场和浓度场的计算采用有限差分法。模型中采用大小两套网格分别进行宏观温度场和微观组织演变的计算，提高了计算效率，使用该模型模拟了铝合金单晶生长以及铝合金在金属模具中的凝固情况，得到了在不同浇注温度下典型的柱状晶向等轴晶转变的三维图形。
英文摘要：Based on Cellular Automaton(CA) model and physical process of nucleation and growth of grains, a three-dimensional CA model for three dimensional simulation of aluminium alloy was developed. The relationship between the growth velocity of a dendrite tip and the local undercooling was calculated according to KGT model. The finite difference method was used to calculate the temperature and solute fields in the calculation domain. In Macro-micro model ,two kinds of grids were used to calculate the temperature field and the evolution of dendrite microstructure, which gear up the speed of compute. The model was applied to predict the growth of single crystal, the solidification of Al in cubic steel mold and three-dimensional image of columnar-to-equiaxed transition (CET) were gotten at three different pouring temperatures.