中文摘要：

采用伪二元相图法对DZ125多元合金进行了简化,并用二维Cellular Automaton（CA）法模拟了合金定向凝固微观组织.通过采用不均匀连续形核模型,在考虑到枝晶生长动力学的基础上,模拟了不同抽拉速度下合金定向凝固组织形貌、枝晶界面形态以及一次枝晶间距的变化,说明树枝晶竞争生长中存在“分枝”与“淹没”的机制;并且随凝固速率的增加,合金凝固组织从分枝较少的胞状树枝晶向分枝发达的树枝晶转变.模拟的一次枝晶间距从凝固速率为50μm/s时的132μm减少到凝固速率为500μm/s时的69μm.模拟结果与实验结果吻合较好.

英文摘要：

Directionally solidified microstructures of DZ125 superalloy have been simulated by 2D Cellular Automation method, in which the DZ125 multicomponent superalloy is simplified as a pseudobinary alloy. Taking account of continuous nucleation model and dendritic growth kinetics, an array of dendritic microstructures, interface morphology and the variation of primary dendritic arm spacing with the growth rate are obtained and investigated. The simulation results show that the dendritic competitive growth has the characteristic of tip-splitting and annihilation during directional solidification. With the increase of the growth rate, the interface morphologies of DZ125 superalloy change from cellular to dendritic pattern. The primary dendritic arm spacing decreases gradually from 132 μm to 55 μm as the growth rate increases from 50 μm/s to 500 μm/s. These simulation results match well with the observations.