基于L-J位错密度模型及CA法的45Cr4NiMoV合金动态再结晶行为

Dynamic recrystallization behavior of 45Cr4NiMoV alloy using Laasraoui-Jonas dislocation density model and cellular automaton method

基于热压缩实验得到的数据,获得了45Cr4NiMoV合金在改进的Laasraoui-Jonas(L-J)位错密度模型中的应变软化参数及应变硬化参数,建立了45Cr4NiMoV合金的动态再结晶模型。采用元胞自动机(CA)方法,应用DEFORM-3D软件对45Cr4NiMoV合金热成形过程中的动态再结晶行为进行有限元分析,并与实验得到的微观组织进行对比。结果表明:当应变速率及变形量一定时,较高的变形温度促使45Cr4NiMoV合金位错及晶界迁移运动加剧,其动态再结晶晶粒尺寸随着变形温度的升高而增大,模拟结果与实验结果较为吻合,验证了所建立的L-J位错密度模型的合理性,说明修正的L-J位错密度模型结合CA能准确预测45Cr4NiMoV合金的动态再结晶微观组织演变过程。

Based on the data of hot compression experiment, the recovery parameter and hardening parameter of 45Cr4NiMoV alloy were calculated for the modified Laasraoui-Jonas dislocation density model, and the dynamic recrystallization model of the 45Cr4NiMoV alloy was established. The dynamic reerystallization behavior of the 45Cr4NiMoV alloy during the hot forming process was simulated using the cellular automaton method and DEFORM-3D software, and the simulation microstructure was compared with the microstructure which was obtained by the hot compression experiment. The results show that at a given strain rate and specified strain deformation condition, the movement of dislocation and grain boundary are more acutely with a higher deformation temperature, and the dynamic recrystallization grain of the 45Cr4NiMoV alloy will be more coarse with the increasing of deformation temperature. The simulated results agree well with the experimental results, it is noted that the modified L-J dislocation density model coupled with the cellular automaton method can predict the microstructure evolution process of the 45Cr4NiMoV alloy precisely during dynamic recrystallization, it also indicates that the parameters of the modified L-J model in this study is reasonable.