FEM Simulation Of Stirring Casting And Fluidity Of SiCp/ZL101A Composite

SiCp/ZL101 A composite is widely used in the field of industry,so it is necessary to study its melt preparation,microstructure and casting properties.Based on the ANSYS FLUENT software,the stirring flow field in the process of stirring casting is simulated.Guided by the simulation results,SiCp / ZL101 A composite was prepared by semi-solid stirring casting process.The microstructure of the composite was observed and analyzed by metallographic microscope,scanning electron microscope and transmission electron microscope.The influence of hot extrusion process and heat treatment process on the mechanical properties of the composite was studied.Finally,based on the Pro CAST simulation,the influence factors of the composite casting fluidity were studied.The design modeler software in the ANSYS software package is used to model the stirring casting equipment(including the stirring paddle,stirring shaft and crucible).Mesh is used to divide the mesh and set the geometry set,and then based on the commercial CFD software ANSYS Fluent,choose MRF model,mix model in multiphase flow model,k-e model in turbulence model,simulate and calculate the influence of the height of agitator,the number of agitator blades,the speed of agitator blade on the mixing flow field(mainly pressure field,velocity field and turbulence field)in the crucible,and analyze the influence of the speed of agitator blade on SiC particle distribution.The simulation results show that when the height of impeller is between 10% and 30% of the melt height,the number of impeller is larger,and the speed of impeller is around 1200 rpm,the uniform distribution of SiC particles is more favorable.15?m SiC particles reinforced 17 vol.% SiCp / ZL101 A composite was prepared by semi-solid stirring casting,and the extruded composite was obtained by hot extrusion.The microstructure of the composite was observed and analyzed by means of metallographic microscope and scanning electron microscope.It was found that the particles in the composite were uniformly distributed,mainly including eutectic silicon,Mg-Si phase and a small amount of iron rich impurity phase.T6 heat treatment process was adopted,and different solution time and aging time were set.The effect of heat treatment process on the structure of the composite was studied.It was found that the eutectic silicon in the composite was the best in shape and precipitated in spherical shape after solution treatment at 540 ? for 12 hours.After that,the tensile mechanical properties of the composites under different preparation and heat treatment conditions were studied by tensile test at roomtemperature.It was found that the mechanical properties of the composites can be significantly improved by hot extrusion and solution aging treatment.The elongation after fracture increased from 2.0% to 11.4% after hot extrusion,while the tensile strength of the extruded composites after solution aging increased from187.0MPa increased to 323.6MPa.The fracture analysis of SEM shows that the fracture of the composite is mainly interface debonding and particle fracture,and a small amount of inclusions are also observed in the fracture of as cast samples.Through Solid Works software,three-dimensional modeling of spiral sand mold for testing the casting fluidity of materials is carried out,which is imported into the mesh module of Pro CAST for grid division,and then into the cast module for pre-treatment.Parameters such as composite material properties,gate flow rate,initial temperature of each part,interface heat exchange conditions,etc.are set,and the calculation results are processed by the viewer module.The effects of SiC particle volume fraction,SiC particle size and pouring temperature on the fluidity of the composite were obtained.At the pouring temperature of 600? and the particle size of 10 ?m,the length of helix decreases from 90.86 cm to 15.05 cm continuously with the increase of SiC particle volume fraction from 1% to 60%;at the pouring temperature of 600? and the volume fraction of 17%,the length of helix increases from 71.57 cm to 87.24 cm with the increase of SiC particle size from 5 ?m to 15 ?m;At 17% volume fraction and 10 ?m particle size,the helix length increased from0.88 cm to 89.81 cm with the pouring temperature increasing from 600? to 700?.