Research On Liquid Extrusion Of Magnesium Alloys

The liquid extrusion which is based on liquid forging was developed a metal formingprocess combining with casting and forging. Liquid metals solidify under pressureconditions and have large plastic deformation in order to obtain the parts which have finestructure and high performance.In this thesis, liquid extrusion process of magnesium alloyis investigated by finite element simulation soft. According to the results, numericalsimulation will guide the mold designing and optimize the process parameters in liquidextrusion process of magnesium alloys. Samples were taken from parts are heat-treated,according to the mechanical properties test results of samples under different heat-treatedconditions, we summarize the optimum heat treatment temperature and time to prepare thesubsequent experiments.To begin with, the mold of liquid extrusion is design. The upper mold move top-downand the liquid metals solidify under pressure conditions. Research on finite elementsimulation of liquid extrusion and solve the computational problem about fluid motion andmechanical motion of the liquid metal at the same time. Through researching the interactaccess between ANSA and simulation software to solve the problem about meshing ofsimulation. Then the file is input into Volume Mesh modular of simulation software todivide volume mesh to obtain the model used in the laboratory.Furthermore, filling and solidification processes of liquid extrusion of magnesiumalloys were investigated by computer simulation software simulation. Through thedifferent parameter of the orthogonal, the optimal process parameters are obtained. Thesimulation results show that the optimized technological parameters are: castingtemperature700℃, die temperature450℃, upper mold speed25mm/s, pressure180MPa,holding time25s.The parts have good properties and high quality of surface under theseparameters.The parts are produced by these parameters, the results of microstructure analysis andmechanical properties testing show that the simulation results are feasibility. The best heattreatment parameters are obtained by the basis the material to solution treatment and aging treatment:415℃×16h solution treatment and220℃×16h aging treatment. The tensilestrength reaches212.53MPa and elongation reaches5.07%. Computer simulation can beused in parameter optimization of liquid extrusion of magnesium alloy, enhancing alloymaterial efficiency, improving the microstructure of material and increasing the property.Mechanical properties of magnesium alloys were prepared for future experiments.