| Particulate-reinforced metal matrix composites (PMMCs) produced by stirring castingmethod exhibit many advantages, including low producing cost, simple fabrication processand highly isotropic properties, and are quite promising in practical application. Theparticulate distribution during PMMCs stirring has significant effect on the castingmechanical properties and physical performances. In this paper through liquid quenchingexperiment and multi-phase flow simulation, the particulate flow and distribution during thePMMCs stirring were investigated.According to the requirements about the particulate distribution analysis for liquidquenching of PMMCs stirring casting, the currible, stirring system, furnace and appendixparts of the liquid quenching apparatus were designed, and then the apparatus was made. Withthe apparatus, A356/SiC_pcomposite slurries were prepared and quenched with differentparticulate adding methods including liquid bottom, semi-solid bottom, liquid top, andsemi-solid bottom methods. The composite appearance and particulate agglomeration wereanalyzed and compared. Hence the method for the particulate adding to Al melt was chosen.In order to study the effects of the stirring parameters on particulate distribution,A356/SiC_pcomposites prepared with different particulate sizes of150μm and50μm, stirringspeeds of150rpm and450rpm, and stirring positions of h10mm and h5mm were made by theexperimental quenching apparatus. The particulate fractions at different locations of theprepared composite were quantitatively measured with micro digital image analysis system.The particulate distributions along radius direction and height were studied, and theparticulate axis distribution maps were plotted. The influences of stirring speeds and positionson the particulate distribution were discussed.Based on liquid-solid multiphase flow model and multiple rotating reference framemodels, mathematical model of PMMCs stirring process was established with considerationof relative flow between liquid and solid phases. It has been applied to the experimentalA356/50μmSiCpstirring, and the composite flow fields and SiC particulate flow anddistribution were calculated and provided. By comparing the simulation results with theexperimental ones, the relationship of stirring condition, composite slurry and particulate flow, and particulate distribution were analyzed. It is indicated that the simulation is agreement withthe experiment and provides evidence for understanding the particulate distribution, whichshow promising of the established model and methods for actual PMMCs stirring preparation.According to the particulate distribution characteristics shown by experiment and simulationstudy, an optimal pouring method for the PMMCs stirring apparatus was suggested. |
