基于3D CA的AZ31镁合金动态再结晶行为研究

Dynamic Recrystallization Behavior of AZ31 Magnesium Alloy Based on 3D CA

摘要:

本文建立了三维元胞自动机(3D-CA)模型，通过热压缩试验和电子背散射衍表征技术(EBSD)，对AZ31镁合金在热变形过程中的微观组织演化规律进行可视化和定量预测。根据试验得出的真应力-应变曲线，确定了3D-CA模型参数在试验条件下的取值，建立了模型参数与变形条件(应变、变形温度和应变速率)之间的关系。利用所建立的3D-CA模型，对AZ31镁合金在热变形过程中的流动行为和微观组织演化进行模拟和讨论。结果表明:再结晶体积分数随着应变的增大而增加，随着变形温度的增大或应变速率降低而增大，提高应变速率或降低温度可以细化再结晶晶粒。模拟结果与实验结果吻合较好，相对误差值在4.5%-16.2%之间，所建立的3D-CA模型能够较准确地预测镁合金AZ31的微观组织演化。

Abstract:

A three-dimensional cellular automata (3D-CA) model was established to visualize and quantitatively predict the microstructural evolution of AZ31 magnesium alloy during hot deformation by thermal compression test and electronic backscatter characterization (EBSD). According to the true stress-strain curve obtained from the test, the values of the parameters of the 3D-CA model under the test conditions are determined, and the relationship between the parameters of the model and the deformation conditions (strain, deformation temperature and strain rate) is established. The flow behavior and microstructure evolution of AZ31 magnesium alloy during hot deformation were simulated and discussed by using the established 3D-CA model. The results show that the recrystallization integral increases with the increase of strain, and increases with the increase of deformation temperature or the decrease of strain rate. Raising strain rate or decreasing temperature can refine recrystallized grains. The simulation results are in good agreement with the experimental results. The relative error is between 4.5% and 16.2%. The 3D-CA model can accurately predict the microstructure evolution of magnesium alloy AZ31.