Preparation Of Al/Mg/Al Clad Plate And Research On Its Interfacial Microstructure/mechanical Properties

The use of magnesium alloys is restricted because of its poor corrosion resistance.However,Aluminum alloys are widely used because of their good corrosion resistance and plasticity.Aluminum alloy is widely used for their good corrosion resistance and plasticity.Therefore,the Al/Mg/Al clad sheets can not only improve the surface corrosion resistance,but also reduce the weight of the sheets and obtain the good mechanical properties.This is of great significance for improving the application of magnesium in aerospace and other fields.In this paper,the preparation and interface properties of Al/Mg/Al composite sheet were studied.Firstly,the rolling process of Al/Mg/Al composite plate was designed according to the related theory,that is,surface treatment,stacking,heating and rolling.The rolling temperature is 350℃,400℃and 450℃and the rolling frequency are 3 passes,the single pass deformation is 30%²0%²0%,and the total pass deformation is 55%.This paper focused on the effect of rolling temperature on the interface structure,mechanical properties and bonding strength of Al/Mg/Al composite sheet.The results showed that the Al/Mg/Al three layers of composite sheet can be successfully prepared at three rolling temperatures,and the Al/Mg/Al composite sheet prepared at 450℃has the highest metallurgical bonding degree,the smallest defect in the middle layer and the maximum thickness of the middle layer.The Al/Mg/Al composite formed at 400℃has the best comprehensive mechanical propertiesSecondly,the composite plate prepared at 400℃was selected and annealed at 250℃（2h,4h,6h）,and the effect of annealing time on the interfacial structure and bonding strength was studied.The results show that after heat treatment,the cracks and pores at the interface of the composite plate disappear basically.With the increasing of the heat preservation time,the thickness of the middle layer of the interface is enhanced and the bonding strength of the interface is increased.Finally,the influence of Zn foil on Al-Mg composite interface was studied by adding Zn foil interlayer between Al and Mg.The results showed that the Al/Mg/Al composite board prepared at 400℃has good interface structure and fewer defects by adding Zn foil.The addition of Zn foil changes the microstructure of the interface,in which the Al side is transformed into Zn-Al solid solution and Mg₂Al₃.The intermediate layer of the Mg side is composed of Mg-Zn eutectic and alpha-Mg,and the addition of Zn foil improves the interfacial bonding strength of the Al/Mg/Al composite plate.