Ultrasonic welding of AZ31B magnesium alloy and pure copper: microstructure, mechanical properties and finite element analysis

Magnesium alloy, copper and other light alloys are widely used in aerospace, new energy vehicles, lightweight manufacturing and other fields due to their excellent mechanical properties, but the connection between light alloys has always been a challenge. Ultrasonic welding is an advanced manufacturing technology that can realize high-strength connection between heterogeneous light alloys. 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 fracture mode of magnesium-copper ultrasonic welded joint is interfacetype 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. During welding, heat is generated in the central area of the solder joint, and then transferred around. The maximum temperature at the interface can reach 550 degrees C. The distribution law of temperature field and plastic deformation field of joint are revealed. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Magnesium alloy, copper and other light alloys are widely used in various fields due to their excellent mechanical properties, but connecting light alloys has always been a challenge. This study conducted ultrasonic welding experiments between AZ31B magnesium and pure copper, studying the fracture, microstructure, tensile properties, and connection mechanism of the joint. A finite element analysis model of the magnesium-copper ultrasonic welding process was established. The ultrasonic connection between magnesium alloy and copper is mainly achieved through the interface diffusion layer formed during the welding process. The maximum joint strength reached 3798 N.