Study On Hot Workability And Microstructure Evolution Of Cast-rolling 3003 Aluminum Alloy

With the popularization and development of new energy electric vehicles,the demand for large-scale power lithium battery cases has increased significantly.Aluminum plates for power lithium-ion batteries will become another important variety of aluminum processed products.At present,aluminum-manganese alloys are widely used in the production of power lithium battery shells because of their excellent comprehensive mechanical properties,good corrosion resistance and blast resistance.In other fields,such as aerospace,automobile,electronics and other indus-tries.They are also widely used.Many scholars have done a lot of research on the 3 series Al-Mn alloy,mainly focusing on the effect of heat treatment on the structure,the effect of heat treatment and different processing techniques on the material structure,or the effect of microalloying ele-ments on the structure.However,there are few studies on the hot workability of 3003 aluminum alloy.In order to improve the molding process,deformation structure,and the comprehensive mechanical properties of the material.It is necessary to systematically study its hot workability and its deformation mechanism.In this paper,Gleeble-3500 thermal simulation test machine is used to conduct hot compres-sion experiments on cast-rolling 3003 aluminum alloy under different deformation conditions.The specific experimental parameters are:the deformation temperature between 350?and 450?,the strain rate between 0.1 s^-1 and 10 s^-1,and the 0.8 maximum true strain.Importing the real-time data collected by the testing machine into Origin,using the polynomial fitting to draw the flow stress curve of cast-rolling 3003 aluminum alloy under experimental conditions.Analyze the in-fluence of different thermal deformation parameters on the flow stress curve of 3003 aluminum alloy.Based on the Arrhenius hyperbolic sine function,the constitutive equation of cast-rolling3003 aluminum alloy is established.On the basis of mention above,the strain factor is added to construct a coupled strain constitutive model of cast-rolling 3003 aluminum alloy.Based on the DMM theory,drawing the thermal processing map of the alloy.Using OM,SEM,EBSD and other characterization methods to study the evolution of the cast-rolling 3003 aluminum alloy micro-structure under different experimental conditions.The main conclusions are as follows:(1)The flow stress curve analysis shows that the flow stress of 3003 aluminum alloy decreases with the increase of temperature and the decrease of strain rate,which shows typical dynamic response characteristics.And based on the flow stress curve,and the Arrhenius function relationship,the constitutive equation of 3003 aluminum alloy is constructed.Considering the in-fluence of the strain variable on the constitutive equation,the established constitutive equation is optimized and improved.(2)Microstructure observation shows that a large number of second phases are precipitated during the thermal compression of the material,which are distributed along the grain boundaries in a chain shape.With the increase of temperature and strain rate,it is conducive to the growth of the second phase in the tissue,and the surrounding small second phase is reintegrated into the matrix.The second phase is nearly distributed at 425°C and 1 s^-1.(3)According to the collected thermal compression data,the material constants of 3003 alu-minum alloy are determined by the method of linear fitting.The constitutive equation of cast-rolling 3003 aluminum alloy is constructed:??=8.5891×10¹³[sinh(0.020901?)]^8.1492exp(_RT^-186829)And further improve the above formula,establish the material coupling strain constitutive equation and has a good predictive effect.(4)The thermal processing map of the material and the electron backscatter diffraction study show that the 3003 aluminum alloy has two best thermal processing windows at 425?,0.1 s^-1and 450?,10 s^-1.In the process of thermal compression,the original crystal grains are destroyed and the equiaxed features are elongated.It is fibrous after heat compression.Dynamic recrystalli-zation is dominated by CDRX,and accompanied by DDRX.