Influence Of Rolling Temperature On The Bonding Behavior,Microstructure And Properties Of Mg/Al Composite Plate By The Corrugated+Flat Rolling

The Mg alloy and Al alloy are rolled and prepared into a composite plate,which can not only take advantage of the Mg alloy's light weight,high strength and impact resistance,but also make the Al alloy's advantages of corrosion resistance and good plasticity be applied.The rolling compound of Mg alloy and Al alloy is one of the most efficient and controllable methods for the modern production of compound materials.The new corrugated-flat rolling(CFR)process and double traditional flat rolling(TFR)process were used to prepare AZ31B/5052 laminates with excellent mechanical properties and good shape at 250-400?.Experimental and numerical simulation methods were used to study the microstructure evolution and mechanical behavior of the composite plate under CFR and TFR hot rolling conditions.Comparing the rolling models of CFR one/two pass and TFR one/two pass,the CFR rolling process combined with the overall temperature of the interface is higher than the composite plate prepared by TFR,in which the plastic deformation at the trough is the largest and the final temperature is the highest(136.66?).The stress and strain at the peak of the two-pass rolled composite plate are smaller than the strain at the valley.The strain value of the flat roll rolled composite plate is between the peak strain and the valley strain,which is similar to the corrugated waist.At the same time,as the temperature increases,the strain changes less.Since the middle joint surface of the CFR rolling process is corrugated,the rolling force fluctuates periodically.Rolling compounding of AZ31 Mg plate and 5052 Al plate was achieved by CFR in one pass under the condition of 250?/37.5%reduction rate,and under the same reduction rate condition,the critical temperature for the bimetallic rolling compound using TFR in one pass was 300?350?.The two-pass rolled composite plates are all combined well,and no cracks appear.The reason why the corrugated roll improves the combination efficiency of Mg and Al bimetals is that there are periodic changes of stress and strain at the peaks and troughs.Local strong stress and shear deformation promote a large number of cracks on the surface to be composited and expose the inner layer of fresh metal,which promotes The embedding ability of the interface metal.The higher overall rolling temperature of the CFR pass makes the bonding surface of the composite plate diffuse faster,and the severe plastic deformation forms a larger range of dislocation migration,resulting in the CFR pass rolling method can achieve Mg/Al at a lower temperature Bimetallic rolling compound.The tensile strength of the CFR-rolled Mg/Al composite plate reaches a peak of 310 MPa at 350?.The tensile strength of the TFR-pass rolled composite plate is lower than that of the CFR-pass rolled composite plate,and the elongation is slightly higher than that of the CFR-pass rolled composite plate.The CFR two-pass composite board is also prepared at 350?.The composite board has the best comprehensive mechanical properties,the maximum tensile stress is 384 MPa,and the elongation is 15.52%.The bonding interface of the three-dimensional structure increases the contact area of dissimilar metals so that The strength is increased,and the embedded bonding interface also increases the mechanical properties of the CFR composite board.EDS analysis of the composite board prepared in the second pass found that there were intermetallic compounds on the joint surface.As the rolling temperature increased,the thickness of the intermetallic compound gradually became thicker,especially after 350?.EDS elemental analysis confirmed that the composition of the intermetallic compound is Mg₁₇Al₁₂,Al₃Mg₂.As the temperature increases,the grain size of the composite plate gradually increases.Due to the large rolling stress at the valley position,it plays a role in grain refinement The location is similar to the grain size of the TFR rolled composite plate.