Study On Mechanical Behavior And Interface Strengthening Mechanism Of Coated Rolled Steel/Aluminum Composite Plate

Steel/aluminum composite plates have excellent advantages such as light weight,high strength,high thermal conductivity and corrosion resistance,which are widely used in various fields including ship joints and wear-resistant bearings.The rolling bonding technology has become a key research direction in the industry and academia due to its advantages of continuous,high efficiency and environmental protection.However,the differences in deformation resistance between steel and aluminum lead to complex plastic metal flow and stress states within the rolled deformation zone,and plastic deformation of steel is difficult to be triggered.The problem of uncoordinated deformation between thick gauge rolled elements is particularly acute.In this paper,based on the team’s research,the coating process of aluminum alloy coating was changed to form a strong bond between the coating and the surface of the steel plate.Then,through a suitable rolling compounding process,the rolling stable preparation of steel/aluminum composite thick plate is achieved.Specific research contents are as follows:Firstly,the rolling models of steel/coating/aluminum clad plates are established by using "the deactivate and reactivate element" method in MSC.Marc software,taking the Ni Cr coating as interlayer metal.Comparing and analyzing the equivalent plastic strain,temperature field,and interface stress state distribution of composite plates with different layer thickness ratios and compression rates.The research results indicate that plastic deformation of composite metals gradually penetrates from the surface metal to the metal interior,with deformation thinning occurring mainly on the aluminum side.In the rolling direction,the side metal is in the state of tension on both sides and compression in the middle,which is beneficial to the deformation and thinning of the steel plate and promotes the coordinated deformation of the clad plate.Secondly,supersonic spraying is used to obtain a Ni Cr coated steel substrate with initial metallurgical bonding,and good steel-coating-aluminum composite plates are obtained by varying the rolling process parameters.Comparative analysis of the fracture morphology of the composite interface reveals that the coating exhibits fracture distribution and exhibits mechanical interlocking and metallurgical bonding in multiple areas,which can further improve the bonding strength of the composite plate.The results of the shear strength and interface micromorphology analysis of the composite plate at different layer thickness ratios and compression rates can verify the accuracy of the finite element analysis model.Finally,the bonding strength of steel-coating-aluminum composite interface can be further improved by changing the spraying method,the spraying thickness and the spraying material.Comparing the interface morphology and bonding strength of steel/aluminum composite plates under different processes,it is found that the thickness of the coating layer and the metal state of the coating interface have a particularly significant impact on the composite characteristics of the steel-coating-aluminum composite interface.The highest bond strength and best interfacial microstructure of the steel/coating/aluminum composite after rolling is achieved by supersonic spraying of0.1mm Ni Cr coating,which is the recommended coating composite process.