Diffusion Bonding Behavior Of Aluminum Alloy Assisted By Acoustic Field

Diffusion welding is a new bonding method because of the small deformation of the workpiece after welding and the small defects at the weld.It has broad prospects.The role of ultrasound in the welding process has attracted more and more attention.The cavitation of ultrasonic in liquid phase welding play a crucial role in the destruction of oxide film.But its role in diffusion bonding is rarely noticed.In this paper,6063 aluminum alloy is used to explore the role of ultrasonic in diffusion welding.Firstly,the Al/Al joint under the action of the ultrasound field is explored.It is found that under the action of the ultrasound field,the effect will be different depending on the temperature when the ultrasonic is applied.When the surface of the aluminum base material is just beginning to contact,the ultrasonic is applied,it helps the fracture of the surface layer and promotes the contact of fresh base metal.Applying ultrasonic at the soldering temperature will destroy the existing connection to some extent.However,the ultrasound field action at any temperature plays a role in refining the grains.Then,the Al/Cu/Al solid-phase diffusion joint under the action of the ultrasound field was explored,and it was found that the atom diffusion rate increased under the action of the ultrasound field.Similarly,the magnitude also varies with the temperature at which the ultrasound is applied,and the application of ultrasonic at the temperature at which the aluminum base material has just softened plastically promotes the bonding of the fresh base metal at the surface,thereby providing the time for later elemental diffusion.Applying ultrasound at the soldering temperature increases the rate of atomic diffusion,resulting in an increase in the diffusion layer.As the ultrasonic time increases,the thickness of the diffusion layer also increases.Finally,the Al/Cu/Al transient liquid phase diffusion joint under the action of ultrasound field is explored.It is found that the thickness of the liquid reaction layer and the morphology of the eutectic structure will be different due to the action of ultrasound.The ultrasonic action at the eutectic reaction temperature accelerates the ratio of the atomic diffusion,promotes the reaction between aluminum and copper,and the increases the thickness of the reaction layer,thereby causing a large number of pores in the reaction layer;When ultrasonic is applied at the soldering temperature,the liquid phase structure in the reaction layer will flow more out of the weld,resulting in a significant decrease in the thickness of the reaction layer,and the eutectic structure in the reaction layer will also change from the dendrites to flaky and massive.