Research On Microstructure Evolution And Control Of Interface Of Compound Extrusion For Mg/Al Alloy

The main purpose of composite extrusion is to produce the composite material of the magnesium core and aluminum shell structure,to protect the magnesium with poor corrosion resistance by aluminum in order to obtain better ratio strength.Bimetallic isothermal extrusion technology as a kind of lightweight structure produced by advanced processing technology,has been brought to the attention of the academic and industry,but for a long time,how to solve the deformation of composite metal coordination and interface bonding strength,has become the technical difficulties of manufacture,have no perfect solution.Based on this,this paper proposes a double on aluminum and magnesium metal extrusion grain structure evolution and the calculation method of grain size distribution,the composite extrusion temperature during the process of evolution model,double metal microstructure evolution model,the constitutive equation and the plastic metal flow the bimetallic isothermal extrusion process optimization control scheme is put forward.The optimization strategy and results are verified with intensity.By hot compression tests,this paper has calculated the dynamic recrystallization kinetics model of AZ31 magnesium alloy and pure aluminum 1100,and set up based on the finite element software Hyper Xtrude secondary development script,derived calculation scripts required theoretical basis,and import it into calculation of forward extrusion experiments to determine the friction model in the process of extrusion,finally get the recrystallized grain size calculation results,and comparing with the actual,discuss the feasibility and calculation methods grain microstructure evolution during the process of extrusion.According to the thermal compression test and the derivation of the thermodynamic model of grain size,the grain size model of AZ31 magnesium alloy and 1100 pure aluminum was determined,and the results of grain size distribution were calculated.By comparing with the actual results,it is verified that the grain size error of the scheme is about 17%,which is suitable for the calculation of grain size in the process of bimetal extrusion.Analysis extrusion technology on the influence of grain size under the different position of time,and it is concluded that grain size in the process of extrusion before entering the bearing with coarse grain area,and in the bearing disappeared after,meet after recrystallization grain size grew up under the condition of deformation conditions.It is concluded that under the condition of meet the deformation temperature,strain effect on the grain size is more obvious,and designed to be used under different process conditions,temperature and strain sensitivity coefficient of effects of grain size changes.