The Preparation And Melt Fluidity Of SiCp/2024Al Composites

Particle reinforced aluminum matrix composites prepared by stir casting method have the characteristics of low cost and mass production.In this paper,particle reinforced aluminum matrix composites were prepared by stir casting.The effects of process parameters of stir casting on the microstructure and properties of the composites and the effects of heat treatment on the mechanical properties of the composites were studied.Finally,the influence factors of the casting fluidity of the composites were studied by means of simulation and experiment.In this paper,SiCp / 2024 Al composites were prepared by semi-solid stirring casting method.The optimal semi-solid stirring temperature was 630 ? and the optimal semisolid stirring time was 25 ?.The particles in the composites were evenly distributed,the interface was well bonded and the porosity was less.The tensile strength of the as cast composite increases with the increase of SiC particle size.The particle size increases from 3.5um to 14 um,and the tensile strength of the composite increases from 184 mpa to 236 mpa.The elongation of the 3.5um composite is the largest,but only 1.27%,and its mechanical properties are poor.After heat treatment,the tensile strength of 3.5?m and 7?m composites increased from 184 mpa and 200 MPa to 235.9mpa and 260 mpa respectively,and the elongation increased from 1.27 and 0.97 to 2.0 and 1.8 respectively.However,the elongation of 11?m and 14?m composites decreased from 0.65 and 0.95 to 0.40 and 0.56 respectively,which was caused by the defect propagation of as cast microstructure.The database of composite materials was established by Solid Works software,and the 3D modeling of the mold for testing the casting fluidity of materials was carried out,which was imported into mesh module for meshing,and then imported into cast module for parameter setting.The parameters such as material properties,gate flow rate,initial temperature of each part,interface heat transfer conditions and so on were set,and the post-processing of calculation results was carried out by using viewer module,The effects of pouring temperature,SiC volume fraction and SiC particle size on the casting fluidity of the composites were obtained.The results show that with the increase of casting temperature,the decrease of volume fraction and the increase of particle size of SiCp,the casting fluidity of the composites increases in a certain range.