Research On The Extrusion Deformation Characteristics Of Magnesium Alloy Copper Cladding

In order to explore the mechanism of copper coating in improving the plastic deformation of magnesium alloy,this paper takes AZ80+0.4%Ce magnesium alloy as the research object,and adopts supersonic flame spraying technology(HVAF)to spray the surface of magnesium alloy round bar with a certain thickness.Copper coating,the change of magnesium alloy substrate before and after spraying was analyzed,and the bonding mechanism between coating and substrate was explored.The microstructure of the coating was analyzed and studied by optical microscope(OM),scanning electron microscope(SEM),energy dispersive analyzer(EDS),and electron backscatter diffraction(EBSD).The Gleeble-3500 thermal simulation testing machine was used to conduct back-extrusion cup-making experiments on the magnesium alloy substrate with copper coating and the magnesium alloy substrate without copper coating.The effect of the adhesion of copper coating on the surface of magnesium alloy on reducing the back-extrusion force of magnesium alloy can explain the mechanism of the deformation of the coating with the deformation of the substrate at the microscopic level.The main research conclusions are as follows:(1)After the reverse extrusion deformation experiment on the Gleeble-3500 thermal simulation testing machine,the obtained load-displacement curve analysis and discussion concluded that the copper coating has an obvious effect on reducing the extrusion forming force of magnesium alloys,but It is not that the thicker the coating,the stronger the effect of reducing the forming force.(2)The thickness of the coating after back-extrusion deformation changes,and the thickness of the back-extruded coating is smaller than that of the non-extruded coating,indicating that the copper coating is deformed along with the deformation of the magnesium alloy.However,different degrees of cracking appeared in the extruded coating,indicating that the accompanying deformation ability is also affected by other factors,and the specific factors need to be further verified.(3)By observing the morphology of the interface between the coating and the substrate and performing energy spectrum analysis on the characteristic points,the bonding method between the coating and the substrate is mainly mechanical occlusion,and there is also a microarea metallurgical bond.After the back extrusion deformation experiment,with the decrease of the strain rate,the time required for deformation increases,which leads to a solid-phase diffusion reaction at the interface between the coating and the substrate,and a diffusion layer is formed.(4)The comparison between the numerical simulation experimental results and the actual reverse extrusion deformation experimental results is not as expected.The thicker the coating thickness is,the better the effect on reducing the forming load is.(5)In the process of reverse extrusion deformation of magnesium alloys,there is dynamic recrystallization,but heating makes its grains grow.If the speed of grain growth is greater than the speed of dynamic recrystallization,the grain size will increase.If the speed of dynamic recrystallization is greater than the speed of grain growth,the {0001} basal texture in the magnesium alloy will decrease;if the speed of dynamic recrystallization is less than the speed of grain growth,the texture of {0001} basal plane will be reduced.will increase.