Numerical Simulation And Experimental Study On Roll Forming Of Mg/Al Composite Sheets By Corrugated Roll

Mg/Al composite sheets have the advantages of light weight,high specific strength of Mg alloy,corrosion resistance and low price of Al alloy.It has been widely used in aerospace,transportation and other fields.The Mg/Al composite sheets produced by the conventional rolling method have disadvantages such as low bonding strength,poor sheet shape,and large residual stress.In this paper,the Mg/Al composite sheets are prepared by the corrugated roll rolling method.The first pass is rough rolling,the rolling scheme of“corrugated roll+flat roll”is adopted,the second pass is finishing rolling,and the up and down rolls are all flat roll.The surface of the Mg/Al composite sheets can be flattened and rolled to the appropriate thickness according to product requirements.The true stress-true strain law of the as-rolled AZ31B was analyzed by thermal compression experiments.The results show that the true stress decreases with the increase of deformation temperature when the strain rate is determined.When the deformation temperature is constant,the true stress increases with the increase of strain rate.A high-precision peak stress constitutive model of the as-rolled AZ31B magnesium alloy at different temperature intervals was constructed.The process of preparing Mg/Al composite sheets by corrugated roll and flat roll was simulated by Deform-3D software.The results show that,in rough rolling,when the reduction rate is 35.0%,the equivalent plastic strain at the trough interface is higher than the peak interface,and the equivalent plastic strain at the interface of the middle is equivalent with the interface of the flat rolled Mg/Al composite sheets.The equivalent stress at the interface of the peak position is higher than the trough position.The equivalent stress at the interface of the peak is the same as the equivalent stress at the interface of the flat roll Mg/Al composite sheets.The rolling force of the flat roll rough rolling Mg/Al composite sheet is higher than that of the corrugated roll rough rolling.In finishing rolling,when the reduction rate is 30.0%,the cumulative equivalent strain at the interface of the trough and the peak position are all higher than the cumulative equivalent strain at the interface of the flat rolled composite sheets.The equivalent stress at the interface of the flat rolled composite sheet is higher than the peak and trough positions.The interface microstructure and element distribution of Mg/Al composite sheets prepared by different processes were analyzed by scanning electron microscopy?SEM?equipped with energy dispersive spectroscopy?EDS?and EBSD.The phases of the interface was measured by X-ray diffractometry?XRD?.The results show that,rough rolling at the 35.0%reduction rate,Mg/Al composite sheet obtains pre-combination.The width of the interfacial transition layer of the trough is wider than the peak.After finishing at 30.0%reduction rate,the bonding quality of the composite sheet was improved,and an intermetallic compound layer mainly composed of Al₃Mg₂ near the 5052 side and Mg₁₇Al₁₂ near the AZ31B side appeared.The mechanical properties of the sheets were tested using a universal tensile tester.The results show that the tensile strength of the rough rolled and finishing rolled composite sheets are higher than that of the annealed component sheets.