Simulation and experimental study of dynamic recrystallization process during friction stir vibration welding of magnesium alloys  

振动搅拌摩擦焊镁合金动态再结晶过程的模拟与实验研究

作　　者：Mahmoud ABBASI Behrouz BAGHERI Farzaneh SHARIFI 

机构地区：[1]Faculty of Engineering,University of Kashan,Kashan,Iran [2]Department of Mining and Metallurgy,Amirkabir University of Technology,Tehran,Iran [3]School of Mechanical and Materials Engineering,Washington State University,Pullman,USA

出　　处：《Transactions of Nonferrous Metals Society of China》2021年第9期2626-2650,共25页中国有色金属学报（英文版）

摘　　要：A two-dimensional cellular automaton(CA)model was utilized to analyze the effect of mechanical vibration on microstructure evolution of AZ91 alloy during friction stir welding(FSW).The simulated results,namely grain topology,grain size distribution,average grain size,and also the dynamic recrystallization(DRX)fraction were compared with measured data.The adequate comparability between FEM and experimental data shows that the CA method can be applied to the analysis of the microstructure progression during the friction stir welding of AZ91 alloy.It is concluded that the dislocation density during the friction stir vibration welding(FSVW)is higher than that in the FSW process and the process of nucleation and grain growth is faster for samples during FSVW compared to FSW.The grain size modification and DRX phenomenon with various vibration frequencies were also simulated in detail during FSVW.It is found that vibration makes nucleation start earlier and decreases the proportion of the incubation period and the percentage of recrystallization as vibration frequency improves.采用二维元胞自动机(CA)模型分析机械振动对AZ91合金在搅拌摩擦焊(FSW)过程中组织演变的影响。将模拟结果,即晶粒拓扑结构、粒度分布、平均晶粒度以及动态再结晶(DRX)分数与实测数据进行比较。结果显示,有限元分析结果与实验数据具有充分的相似性,CA方法可用于搅拌摩擦焊AZ91合金组织演变的分析。与FSW相比,振动搅拌摩擦焊(FSVW)处理的样品中位错密度更高,形核和晶粒长大也更快。对FSVW过程中不同振动频率下的晶粒度改变和DRX现象经过详细模拟后发现,振动使形核开始时间提前,随着振动频率的提高,孕育期和再结晶的比例降低。

关 键 词：friction stir welding VIBRATION simulation grain size dynamic recrystallization cellular automaton model 

分 类 号：TG453.9[金属学及工艺—焊接]