Study On Numerical Simulation And Mold Design Of Superplastic Forming Of Magnesium Alloy Coupler

The wrought magnesium alloy has been widely used in the field of transportation equipment because of its light weight,high specific strength and specific rigidity,and good damping performance.However,magnesium alloy because of its plastic processing molding temperature range is narrow,strain-sensitive characteristics,the use of conventional plastic molding method can only shape the simple parts,and the formation of brittle or overburden.As an advanced plastic forming method,superplastic forming method is able to carry out disposable plastic molding of complex parts,thus shortening the process flow and reducing the machining capacity,so as to realize the near net forming.In this paper,a superplastic die forging process was proposed for the complexly coupled transition coupler,and the AZ80M magnesium alloy was used as the coupler material.The superplastic die forging process and experimental study were carried out.The main work as follows:The experimental results show that when the experimental temperature is 300?-400? and the strain rate is 1×10-4s-1-1x10-2s-1,the material of the AZ80M magnesium alloy showing a typical dynamic recrystallization behavior.The constitutive equation of elevated-temperature compression of AZ80M magnesium alloy was established.According to the size and structural characteristics of the coupler,the forging optimization design is carried out,and the forming method is determined as the superplastic precision die forging.Design of the mold:mold design for the split,that is,forming a mold into several modules,through the outer mold barrel to combination modules together,effectively reducing the cost of the mold.At the same time,for the complex parts can not be directly through the superplastic precision molding,through the mold of a reasonable block,you can achieve superplastic precision molding.According to the constitutive equation and the DEFORM-3D plastic simulation software,the simulation and optimization of the process parameters of the coupler are carried out.It is found that the molding.load decreases with the increase of temperature,but the influence of temperature on the forming load is weakened.According to the simulation results,the optimum process of the coupler molding process has been designed.Successfully produced a number of smooth surface and complete filling coupler samples.The results show that the forming process can realize the near-net plastic forming of the magnesium alloy complex parts,and shorten the molding time and improve the forming efficiency.The heat treatment process is applied to the transition coupler,and then carried out on-site 500KN tensile test and 550KN compression test,found that the coupler was not significantly deformed and damaged,so successfully passed the application testing.The results show that the mechanical properties of the magnesium alloy couplings molded by the process scheme designed in this paper are in accordance with the mechanical properties of the existing couplers.