Abstract. Based on the fundamental metallurgical principles, a modified cellular automaton model which considers the influences of uneven distribution of dislocation density and smallsized precipitated particles was proposed to simulate the dynamic recrystallization (DRX) performances of steels with the three kinds of equivalent particle`s size. The results show that the model can truly simulate the nucleation order and multi-round feature of DRX as well as the law of small-sized precipitated particle`s retarding DRX; The finer are the particles, the stronger gets the action of their pinning grain boundary.
IntroductionDynamic recrystallization (DRX) plays a significant role in thermo-mechanical processing due to its improving mechanical properties by refining grain [1]. In the process of DRX, grain boundary migration decides the mean grain size of microstructure and is retarded by micro-alloying elements in metallic alloys as pinning effect of precipitated particles (Zener pinning) [2]. Many researches have been focused on DRX in recent decades. In these researches, if only the kinetics is of interest, the Johnson-Mehl-Avrami-Kolmogorov (JMAK) approach [3,4] can present a reasonable description. If information on microstructure development during DRX is simultaneously required, the models with adequate temporal and spatial resolution are needed. Therefore, numerical models, such as Q state Monte Carlo (MC) [5,6], phase field (PF) [7] and cellular automaton (CA) [8][9][10][11][12][13][14][15] have been proposed to simulate DRX. Compared with MC and PF method, the CA method is used more because of its more flexible and adaptable to temporal and spatial scale. Goetz and Seetharaman[8] first applied CA method to simulate the DRX features such as the necklace type of microstructures at high strain rates and its kinetics obeying the JMAK equation. Then, many researchers have been focused on DRX simulation based on the CA method [9][10][11][12][13][14][15]. However, the investigation with regard to the effects of precipitated particles on DRX is little. This work thoroughly simulates the DRX microstructure evolution in three steels with the different mean sizes and same volume fraction of precipitated particles by using a new CA model, respectively, and discusses the related effects.