镁/铝水下搅拌摩擦搭接焊接头组织与性能研究

为了控制界面金属间化合物的生成量及分布，采用水下搅拌摩擦搭接焊技术，在旋转速度1 180 r/min、焊接速度47.5 mm/min条件下，制备了无宏观缺陷的AZ31Mg/6061Al焊接接头，并采用OM、SEM、EDS以及XRD技术对接头显微组织、元素分布、剪切强度及断口表面进行分析。结果显示:搭接界面过渡层厚度仅约为2.01 μm；界面过渡层主要由Mg、Al、Al12Mg17以及少量的Mg2Al3组成；接头剪切强度达到5.3 kN，且Mg/Al搭接焊焊接断裂发生在过渡层脆性IMCs处。研究表明，SFSLW可有效抑制Mg/Al界面IMCs的生成，并能显著提高接头的剪切强度。

Structure and Mechanical Properties of Magnesium/Aluminum Joint by Submerged Friction Stir Lap Welding

In order to control the amount and distribution of intermetallic compounds in the interface, the AZ31Mg/6061Al welded joint without macroscopic defects was prepared by submerged friction stir lap welding at the rotating speed of 1 180 r/min and the welding speed of 47.5 mm/min. The microstructures, element distribution, shear strength and fracture surface of the joint were analyzed by OM, SEM, EDS and XRD. The results show that the thickness of the interface transition layer is only about 2.01 μm; the interface transition layer is mainly composed of Mg, Al, Al12Mg17 and a small amount of Mg2Al3. The shear strength of the joint reaches 5.3 kN, and the fracture of Mg/Al lap welding occurs at the brittle IMCs of the transition layer. The results show that SFSLW can effectively inhibit the formation of IMCs at Mg/Al interface and significantly improve the shear strength of the joint.