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采用基于溶质扩散控制模型CA方法对Ti-45at.%Al合金定向凝固过程中显微组织演化过程进行了数值模拟.模拟结果表明,在温度梯度较高时,初生晶核间距无论大小,均可通过分枝或竞争生长而使一次胞晶/枝晶间距得到调整.在抽拉速度一定情况下,随着温度梯度增加,胞晶/枝晶间距减小,在温度梯度一定情况下,随着抽拉速度增大,观察到胞晶/枝晶混合结构,混合结构区随温度梯增大而增大,模拟结果与实验观察相符合.
The evolution of microstructure during the directional solidification of Ti-45at.% Al alloy was numerically simulated by the solute-diffusion controlled model CA. The simulation results show that the primary nuclei spacing can be large or small at high temperature gradient Through the branch or competitive growth and a cell / dendrite spacing is adjusted at a certain draw speed, as the temperature gradient increases, the cell / dendrite spacing decreases, under certain temperature gradient, with the The pull-out velocity increased, and the mixed structure of cell / dendrite was observed. The mixed structure area increased with the increase of temperature gradient, and the simulation result was consistent with the experimental observation.