Abstract:A three-dimensional (3-D) modified cellular automaton (MCA) method was developed for simulating the dendrite morphology of cubic system alloys. Two-dimensional (2-D) equations of growth velocities of the dendrite tip, interface curvature and anisotropy of the surface energy were extended to 3-D system in the model. Therefore, the model was able to describe the morphology evolution of 3-D dendrites. Then, the model was applied to simulate the mechanism of spacing adjustment for 3-D columnar dendrite growth, and the competitive growth of columnar dendrites with different preferred growth orientations under constant temperature gradient and pulling velocity. Directional solidification experiments of NH₄Cl-H₂O transparent alloy were performed. It was found that the simulated results compared well with the experimental results. Therefore, the model was reliable for simulating the 3-D dendrite growth of cubic system alloys.

Key words: modified cellular automation; 3-D dendrite morphology; dendrite growth; directional solidification; NH₄Cl-H₂O transparent alloy