LZ50钢静态再结晶机理及元胞自动机模拟  

Static Recrystallization Mechanism of LZ50 Steel and Cellular Automata Simulation

作　　者：师先哲 杜诗文[1,2] SHI Xianzhe;DU Shiwen(School of Materials Science and Engineering, Taiyuan University of Science and Technology, Taiyuan 030024;Shanxi Key Laboratory of Metal Forming Theory and Technology, Taiyuan 030024)

机构地区：[1]太原科技大学材料科学与工程学院,太原030024 [2]金属材料成形理论与技术山西省重点实验室,太原030024

出　　处：《机械工程学报》2019年第14期43-52,共10页Journal of Mechanical Engineering

基　　金：国家自然科学基金资助项目(51305289,51871158)

摘　　要：LZ50钢是经典的车轴钢,但在其锻造过程中组织演变方面的研究存在很多不足。为了探究工艺参数对组织演变的影响规律,利用Gleeble-3500热模拟试验机对LZ50钢进行双道次热压缩模拟试验以分析其静态再结晶行为,发现高温、高应变及高应变速率下,静态再结晶体积分数越大,温度及应变对静态再结晶体积分数影响也越大,根据应力应变曲线构建了静态再结晶动力学模型。元胞自动机模拟结果与试验结果一致,可以对LZ50钢静态再结晶行为进行预测。模拟发现:温度越高,新晶粒生长速度越快;应变及应变速率越高,新晶核生成速度越快。电子背散射衍射(EBSD)技术对形变后LZ50钢的微观组织取向分析表明:LZ50钢静态再结晶的形核方式为晶界弓出形核,在原始晶粒的晶界两侧存在位错密度差,晶界会向位错密度高的一侧迁移,促进晶核的产生。得到的组织演变规律对生产加工具有指导意义。Although LZ50 steel is a classic axle steel, there are many deficiencies in the research of microstructure evolution in the forging process. In order to investigate the influence of process parameters on the evolution of microstructure, the static recrystallization behavior of LZ50 steel is analyzed by double-pass hot compression test on Gleeble-3500 thermal simulation machine. It is found that the static recrystallization volume fraction is higher at high temperature, high strain and high strain rate. Temperature and strain have a great influence on the static recrystallization volume fraction. The static recrystallization kinetics model isconstructed according to the stress-strain curve. The simulation results of cellular automata are consistent with the experimental results, which can predict the static recrystallization behavior of LZ50 steel. It can be seen from the simulation that the higher temperature is, the faster new grain growth rate will be, however, the higher strain or strain rateis, the faster the nucleation will be.The electron backscatter diffraction (EBSD) technique is used to analyze the microstructure orientation of LZ50 steel after deformation. The nuclei of static recrystallization forms by bulging of initial grain boundaries. There is a difference in dislocation density onboth sides of original grain boundary. The grain boundary will migrate to the side with high dislocation density to promote the generation of new nuclei. The obtained evolution law of the organization has guiding significance for production and processing.

关 键 词：LZ50钢 静态再结晶 元胞自动机 形核机理 

分 类 号：TG316[金属学及工艺—金属压力加工]