Abstract:A 3D stochastic modeling was presented to simulate the dendritic grains during solidification process of aluminum alloy. Shape functions were proposed in 2D and 3D to describe equiaxed dendritic shape. A growth model was presented to describe the growth of a nucleated grain and the capturing of the neighboring cells. On growing, each grain continues to capture the nearest neighboring cells to form the final grain shape. If a neighboring cell has been captured by other grains, the growth along this direction stops, which can reflect the grains impingement phenomenon occurring in solidification process. 2D and 3D calculations were performed to simulate the evolution of equiaxed dendritic grains. In order to verify the modeling results, step-shaped sample castings were cast in sand mold. The microstructure in various positions of the sample was observed. In addition the quantitative metallographic analysis also has been done to evaluate the grain size. Experimental and numerical results agree well.

Key words: Al alloy; stochastic modeling; microstructure simulation; equiaxed dendritic grain