Ultrasonic Welding of AZ31B Magnesium Alloy and Pure Copper: Microstructure, Mechanical Properties and Finite Element Analysis

Abstract

Abstract Ultrasonic welding is known as "green welding manufacturing technology" because of its fast, energy-saving, clean and pollution-free technical characteristics. Therefore, ultrasonic welding technology has a wide application prospect in aerospace, automobile and other fields. In this study, ultrasonic welding between AZ31B magnesium and pure copper are carried out. The fracture, microstructure and tensile properties of the joint are studied, and its connection mechanism is analyzed. The finite element analysis model of magnesium-copper ultrasonic welding process is established. The analyses of test results show that the fracture mode of magnesium-copper ultrasonic welded joint is interface-type fracture. The joint strength reaches the maximum value of 3798 N. The ultrasonic connection between magnesium alloy and copper is mainly realized by the interface diffusion layer formed in the welding process. The main component of the interface diffusion layer is mg2cu. The growth trend of interface diffusion layer is revealed. The analyses of FEM results show that the heat is generated in the central area of the solder joint, and then transferred around. The maximum temperature at the interface can reach 550 ℃. The distribution law of temperature field and plastic deformation field of joint are revealed.