Al/Mg 异种合金搅拌摩擦焊的材料流动可视化和数值模拟研究  

Visualization and Numerical Simulation of Material Flow in Al/Mg Dissimilar Friction Stir Welding

作　　者：宋波[1] 翟洋洋 左敦稳[3] 邓永芳[4] Song Bo;Zhai Yangyang;Zuo Dunwen;Deng Yongfang(Lanzhou University of Technology,Lanzhou 730050,China;Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China;Jiangxi University of Science and Technology,Ganzhou 341000,China)

机构地区：[1]兰州理工大学机电工程学院,甘肃兰州730050 [2]兰州理工大学,甘肃兰州730050 [3]南京航空航天大学,江苏南京210016 [4]江西理工大学,江西赣州341000

出　　处：《稀有金属材料与工程》2020年第5期1483-1490,共8页Rare Metal Materials and Engineering

基　　金：Natural Science Foundation of Gansu Province(18JR3RA146,18JR3RA147)。

摘　　要：采用切片法研究了搅拌摩擦焊接(FSW)接头的材料流动。通过对接头的三维重建,实现了流动材料的可视化,讨论了接头材料的流动模式和缺陷产生的原因。基于计算流体力学(CFD)和多相流理论,建立了FSW过程中铝合金/镁合金材料流动的三维数学模型。通过在数值模型中加入分布的示踪粒子,对不同连接参数下的材料流动模式进行分析和预测。结果表明:接头上部材料流动强烈,材料整体向前进侧迁移,接头中部前进侧镁合金向接头前部迁移,暂时形成的空腔由后退侧迁移来的铝合金填充。当不恰当的工艺参数使材料流动不充分时,未被完全填充的空腔会形成孔洞缺陷。接头材料整体主要以层流为主。在满足材料流动热输入需要时,接头材料的流动模式基本不发生改变,在高转速过热条件下,材料的迁移距离和混合模式会发生改变,2种材料围绕搅拌头以层流模式多次越过对接线并充分混合,同时在后退侧产生紊流现象。The flow mode of materials is closely related to the formation of joint structure,which has a crucial influence on the mechanical properties of joints for friction stir welding(FSW).The material flow of the joint was studied by slicing method which was adopted to observe different layers of dissimilar friction stir butt welding.The visualization of the material flow was accomplished by 3D reconstruction of the joint,which shows the flow pattern of the joint and the cause of the defect.The three-dimensional mathematical model of the flow of Al/Mg materials in FSW process was established based on computational fluid dynamics(CFD)and multiphase flow theory.The material flow patterns were analyzed and predicted under different welding parameters by the distribution of tracing particles added in numerical models.Results reveal that the flow of material in the upper part of the joint is strong,and the material moves to the front of tool as a whole.The magnesium alloy in the middle part in the advancing side of the joint moves forward to the front of the tool,and the temporarily cavity is filled with aluminum alloy from the retreating side.The cavity which is not completely filled will form a hole defect when the material flow is insufficient due to improper process parameters.The whole joint material is mainly laminar flow.The flow mode of joint material is basically unchanged when the heat input is satisfied.The transfer distance and mixing mode of material will change under the condition of high rotation speed or overheat.The two materials cross the butt line for many times in the mode of laminar flow around the tool and are fully mixed when the turbulence occurs on the retreating side.

关 键 词：异种搅拌摩擦焊 2024铝合金 AZ31镁合金 材料流动 数值模拟 

分 类 号：TG453.9[金属学及工艺—焊接]