基于CEL模型的AZ91D镁合金搅拌摩擦焊材料流动行为数值模拟  

Numerical Simulation of Material Flow Behavior of AZ91D Magnesium AlloyFriction Stir Welding Based on Coupled Euler-Lagrange Model

作　　者：刘澳 曹岳 华鹏[1] 李先芬[1] LIU Ao;CAO Yue;HUA Peng;LI Xianfen(School of Materials Science and Engineering,Hefei University of Technology,Hefei 230009,China)

机构地区：[1]合肥工业大学材料科学与工程学院,合肥230009

出　　处：《焊管》2024年第11期39-45,共7页Welded Pipe and Tube

基　　金：安徽省自然科学基金资助项目“铁素体耐热钢搅拌摩擦焊接接头组织演变和性能特征研究”(项目编号1808085ME150)。

摘　　要：基于耦合欧拉-拉格朗日(CEL)方法,利用Johnson-Cook本构模型建立了AZ91D镁合金搅拌摩擦焊热力耦合有限元模型。利用粒子示踪技术并结合温度场、应变场和欧拉场探究了焊接过程的材料流动行为。结果显示,高温区域位于后退侧的搅拌针后方,焊核区后退侧的温度高于前进侧约40℃;峰值温度随旋转速度的增加和焊接速度的减小而升高,高温区域面积也相应增加;焊接速度对峰值温度的影响小于旋转速度;等效应变场与温度场的分布规律基本一致,高温区域塑性应变相应较大。轴肩影响区的材料在轴肩的挤压及剪切共同作用下在后退侧形成飞边。焊核区材料从搅拌针前方移动到后退侧,并在前进侧搅拌针后方完成回填。当旋转速度增加到950 rpm时,热输入过高,材料流失,会在前进侧底部形成隧道缺陷。Thermal⁃mechanical coupling finite element model of AZ91D magnesium alloy friction stir welding was established based on the Coupled Euler⁃Lagrange(CEL)method and Johnson⁃Cook constitutive model.The material flow behavior during the welding process was investigated by using tracer particles technique and combining temperature field,strain field and Euler field.The results show that the high temperature zone is located behind the stirring pin on the retreating side,and the temperature at the retreating side of the weld nugget is about 40℃higher than the advancing side.The peak temperature increases with increasing rotation speed and decreasing of welding speed.The area of high temperature region increases accordingly.The effect of welding speed on peak temperature is less than that of rotation speed.The distribution law of the equivalent strain field and temperature field is basically the same,and the plastic strain is correspondingly larger in the high temperature region.The material in the shoulder affected zone forms flash on the retreating side under the joint action of extrusion and shear of the shoulder.The material in the weld nugget moves from the front of the stirring pin to the retreating side and completes the backfill behind the stirring pin on the advancing side.When the rotation speed is increased to 950 rpm,the heat input is too high and material is lost,and the tunnel defects will be formed at the bottom of the advancing side.

关 键 词：搅拌摩擦焊 AZ91D镁合金 耦合欧拉-拉格朗日模型 温度场 材料流动行为 

分 类 号：TG453.9[金属学及工艺—焊接]