Optimization of deformation parameters of dynamic recrystallization for 7055 aluminum alloy by cellular automaton  

基于元胞自动机法的7055铝合金动态再结晶变形参数优化（英文）

作　　者：Tao ZHANG Shi-hong LU Yun-xin WU Hai GONG 张涛;鲁世红;吴运新;龚海(南京航空航天大学机电学院,南京210016;中南大学机电工程学院,长沙410083)

机构地区：[1]College of Mechanic and Electrical Engineering, Nanjing University of Aeronautics and Astronautics,Nanjing 210016, China [2]School of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China

出　　处：《Transactions of Nonferrous Metals Society of China》2017年第6期1327-1337,共11页中国有色金属学报（英文版）

基　　金：Projects(51175257,51405520) supported by the National Natural Science Foundation of China

摘　　要：In order to simulate the microstructure evolution during hot compressive deformation,models of dynamic recrystallization(DRX)by cellular automaton(CA)method for7055aluminum alloy were established.The hot compression tests were conducted toobtain material constants,and models of dislocation density,nucleation rate and recrystallized grain growth were fitted by leastsquare method.The effects of strain,strain rate,deformation temperature and initial grain size on microstructure variation werestudied.The results show that the DRX plays a vital role in grain refinement in hot deformation.Large strain,high temperature andsmall strain rate are beneficial to grain refinement.The stable size of recrystallized grain is not concerned with initial grain size,butdepends on strain rate and temperature.Kinetic characteristic of DRX process was analyzed.By comparison of simulated andexperimental flow stress–strain curves and metallographs,it is found that the established CA models can accurately predict themicrostructure evolution of7055aluminum alloy during hot compressive deformation.为了研究7055铝合金在热压缩过程中的组织演变规律,基于元胞自动机法(CA)建立7055铝合金动态再结晶(DRX)模型。为了获得模型的材料参数,进行单道次热压缩实验,通过最小二乘法拟合获得7055铝合金的位错密度模型、形核率模型和再结晶晶粒长大模型。研究应变、应变速率、变形温度和初始晶粒尺寸对热压缩过程中显微组织演变的影响。结果表明:在热压缩过程中,动态再结晶使材料晶粒明显细化。大应变、高温和低应变速率有利于晶粒细化;动态再结晶晶粒的稳态晶粒尺寸与初始晶粒大小无关,而取决于温度和应变速率的变化;分析热压缩过程动态再结晶动力学规律。由CA仿真流变应力值和仿真组织图与实验结果的对比可知,所建立的基于CA法的动态再结晶模型能有效地预测7055铝合金在热变形过程中的动态再结晶组织演变规律。

关 键 词：7055 aluminum alloy cellular automaton dynamic recrystallization hot compression grain refinement 

分 类 号：TG146.21[一般工业技术—材料科学与工程]