搅拌摩擦焊界面摩擦及材料流动行为仿真  

Modeling and Simulation of Interface Friction and Material Flow Behavior during Friction Stir Welding

作　　者：乔俊楠 史清宇[1,2] 陈树君[3,4] 韩阳[3,4] 杨诚乐 周梦然 陈高强[1,2] QIAO Junnan;SHI Qingyu;CHEN Shujun;HAN Yang;YANG Chengle;ZHOU Mengran;CHEN Gaoqiang(Department of Mechanical Engineering,Tsinghua University,Beijing 100084,China;State Key Laboratory of Tribology,Tsinghua University,Beijing 100084,China;Engineering Research Centre of Advanced Manufacturing Technology for Automotive Components,Beijing University of Technology,Beijing 100124,China;Institute of Intelligent Forming Equipment and System,Faculty of Materials and Manufacturing,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]清华大学机械工程系,北京100084 [2]清华大学先进成形制造教育部重点实验室,北京100084 [3]北京工业大学汽车结构部件先进制造技术教育部工程研究中心,北京100124 [4]北京工业大学材料与制造学部智能成型装备与系统研究所,北京100124

出　　处：《电焊机》2023年第3期15-21,共7页Electric Welding Machine

基　　金：国家自然科学基金面上项目(52175334);国家自然科学基金重点项目(52035005)。

摘　　要：采用计算流体力学(CFD)方法研究了6061铝合金搅拌摩擦焊过程中的界面摩擦行为与材料流动行为。通过在搅拌头-工件界面采用剪切力边界条件,实现了焊接过程中界面摩擦与材料流动的完全耦合分析。结果表明,搅拌头与工件间的界面摩擦行为呈现显著的非均匀特征:轴肩芯部及环形槽内呈近似黏着摩擦,轴肩外缘区域呈滑动摩擦;搅拌针侧面呈现不同程度的滑动状态,界面滑动比例随其到轴肩的距离增加而增加。摩擦界面附近存在厚度为0.66~4 mm的低粘度区。在低粘度区,工件上部材料流动速度可达0.17 m/s,应变率可达85.7 s^(-1);在工件下部材料流动速度可达0.017 m/s,应变速率可达11.7 s^(-1)。从材料流经低粘度区的流动路径来看,搅拌摩擦焊过程材料流动呈现多圈旋转及直通两种模式。仿真得到的温度、低粘度区形状及标记材料沉积位置均得到了实验结果的印证。In this paper,the interface friction and material flow behavior of 6061 aluminum alloy during friction stir welding are studied by computational fluid dynamics.By adopting the shear stress boundary condition at the interface between the tool and the workpiece,the analysis of interface friction and material flow is realized in a fully coupled manner.The results show that the interfacial friction behavior between the tool and the workpiece presents significant non-uniform characteristics:approximate sticking friction ispresent atthe annulargroove of the shoulder,and slidingfriction ispresent at the periphery of the shoulder.The interfacial sliding in different degrees is present at the pin side,and the sliding index of the interface increases with the distance from the shoulder.There is a low viscosity zone with a thickness of 0.66~4 mm near the friction interface.In the low viscosity region,the material flow velocity on the upper portion of the workpiece reaches 0.17 m/s,and the strain rate reaches 85.7 s^(-1).On the lower portion of the workpiece,the material flow velocity reaches 0.017 m/s and the strain rate reaches11.7 s^(-1).Regarding the material flow path through the low viscosity zone,the material flow presents two modes:multi-circle rotation and straight-through flow.The simulated temperature,geometry of low viscosity zone and deposition position of marker materials are validated by the experimental results.

关 键 词：计算流体力学 界面摩擦行为 材料流动 低粘度区 

分 类 号：TG456.9[金属学及工艺—焊接]