| The magnesium matrix composites of double metal interpenetrated by network structurewhich chose AZ31magnesium alloys as the matrix alloys and chose304stainless wires as thereinforcement were obtained by Pressure Impregnation Technology. This composite materialcan avoid not only the low strength and hardness of Mg alloys, but also the low toughness of theceramic reinforced magnesium matrix composites. It can intensify the joint tightness betweenthe matrix and reinforcement and refine grains to improve and enhance the mechanicalproperties of the material by extrusion forming process. To analyze the material’s deformationbehavior and the distribution law of effective stress and strain and their actions influenced byextrusion process parameters, the simulations of the extrusion process of the material have beendone by DEFORM-3D, the finite element analysis software.Firstly, based on the mixture law and the basic theories of the finite element, therigid-plastic finite element model which concludes geometric model and mathematical modelof the magnesium matrix composites with double metal interpenetrated by network structurewas constructed. In order to testify the correctness of the mathematical model, the compositesmaterials were obtained by using the synthesis technology and preparation method and wereextruded with the practical physics experiments. With the results of the effective stress andstrain and equivalent strain rate which acquired from the experiments, the verification analysisof mathematical model of the material was done and the correct model was constructed.The finite element model of material was imported into DEFORM-3D software to carryout finite element simulation analysis for its extrusion process, the simulation results show thatthe surface parts of extruded material sample had obviously grain refinement at the beginningof the extrusion stage, the network cell of most central material parts did not change. However,both the surface and central parts of extruded material sample had obviously grain refinementin the continuous extrusion stage; the load as stroke curve of the sample can be divided intothree stages: slow increase phase, rapid increase phase and basically stable stage. The risingextrusion temperature would reduce the load value, moreover, the size of extrusion ratio andextrusion speed could improve load value; the equivalent strain of the surface parts of extrudedmaterial sample was greater than its central parts, and the temperature had little effect on the equivalent strain values, if increased the extrusion ratio could increase the size of the equivalentstrain and reduce the uniformity of its distribution, and improved the speed of extrusion to makethe strain increase firstly and then decrease which can improve its distribution uniformity. Theequivalent stress of extruded samples mainly concentrated in the near extrusion cavity andextrusion hole, and the equivalent stress of the surface parts of extruded material sample wasalso greater than its central parts, and the value of equivalent stress could be reduced byimproving the extrusion temperature, and it could be increased by improving the material flowand deformation uniformity, extrusion speed and extrusion ratio, these measures wereinfluential in the distribution of effective stress.In order to analyze the influence of the extrusion process parameters’ change on theeffective stress and strain of the material synthetically, the simulation of the extrusion processof the magnesium matrix composites with double metal had been done according to theorthogonal test. The influence degrees of the extrusion process parameters on the test indexwere determined based on the simulation results, and the best combination of extrusionprocess parameters was obtained, that the extrusion temperature, extrusion ratio and extrusionspeed were set at673K,25and3mm/s respectively. It has a significant theoretical guidancemeaning to the practical production of the material. |
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