动态再结晶过程的定量化可视化元胞自动机模拟

Quantitative and Visual Simulation of Dynamic Recrystallization Using Cellular Automation Method

以热加工过程的金属学理论为基础,将金属的宏观热塑变形参数和内部能量状态引入以正六边形为基元的元胞自动机仿真方法,建立定量化、可视化的动态再结晶二维元胞自动机模型。模型中充分考虑了形核率、临界形核位错密度、位错密度增长以及再结晶晶粒长大驱动力和内部能量状态等多方面因素,可模拟加工硬化、动态回复、形核以及再结晶晶粒长大等一系列过程。利用该模型以纯铜为例对不同温度、不同应变速度下的动态再结晶过程进行模拟,再现动态再结晶形核、晶粒长大的微观组织演变过程,定量分析动态再结晶的动力学特征,并在该模型的基础上分析应变速率对动态再结晶过程以及再结晶晶粒尺寸的影响。模拟结果与相同热变形条件下的纯铜试验结果基本吻合。

Based on the metallurgical principles of hot working process,the parameters of plastic deformation and energy state are introduced into the cellular automaton algorithm in the form of hexagon-motif cell.With the two-dimensional hybrid model,the quantitative and visual simulation of dynamic recrystallization is carried out.In this model,the nucleation rate,critical dislocation density of nucleation,increase of dislocation density and driving force for grain growth,especially energy state,are taken into account thoroughly.A series of processes such as the work hardening,dynamic recovery,nucleation and growth of recrystallization grains can be simulated.By employing the model,the dynamic recrystallization processes of pure copper under different temperature and strains rates have been simulated.Microstructure evolution of dynamic recrystallization,especially nucleation and grain growth,is directly shown,and the growth kinetics of dynamic recrystallization is obtained.The effects of strain rate on dynamic recrystallization process and growth of recrystallization grains are discussed on the base of the model.The simulated results agree well with experimental results.