Study On Shear Connection Technology Of Aluminum Alloy

With the rapid development of petrochemical industry,the application and bonding technology of lightweight aluminum alloy have been popularized.Solid state connection technology has become a widely used connection method for sheet metal and structural parts.The solid state shear connection technology is a fast solid state connection method without fusion welding defects,which can be used for the connection processing of the same metal and dissimilar metal.In this paper,the experimental process of aluminum alloy shear connection is realized by using shear extrusion connection device.The influence of different shear connection parameters on mechanical properties and microstructure of aluminum alloy was emphasized.The main research contents are as follows:According to the working principle of shear extrusion connection,the equipment of shear connection is designed and installed.By controlling the experimental parameters such as connection temperature,connection speed,cutting edge stroke,holding time and post-connection heat treatment process,the influence of each parameter on the connection performance was studied.The results show that the shear connection of aluminum alloy can be realized with good bonding strength and plasticity in the process range of connecting temperature from 400℃ to500℃,connecting speed from 40mm/s to 87.5mm/s,and cutting edge stroke from 37 mm to43mm.The tensile mechanical properties of aluminum alloy shear joints gradually improve with the increase of joining temperature,but the microhardness of connected samples decreases with the increase of joining temperature.The slower the shear connection speed,the better the plasticity of the connected sample.With the increase of blade stroke,the strength of the material is improved and the elongation is reduced.As the holding time increases,the tensile properties decrease,while the microhardness increases first and then decreasesThe microstructure of aluminum alloy was characterized and analyzed,and the mechanism of excellent shear bonding performance of aluminum alloy was studied deeply.The fracture morphology of the connecting zone of samples under all processes is dimple,which is typical ductile fracture,indicating that atomic bonding occurs between metals in the connecting zone and new grain structure is formed,so it can reach the strength equivalent to that of matrix.It is analyzed that oxide inclusion is an important factor affecting the performance of steel shear connection.Aluminum alloy because there is no inclusion of oxide layer at the interface,so the base metal fully contact and diffusion fusion to form a complete structure.In addition,the grain size in the bonding zone of aluminum alloy after shear connection is refined,and the synergistic effect of grain strengthening and texture of the second phase improves its comprehensive mechanical properties.