Study On Technology And Properties Of SiCp/A356 Composite Prepared By Stirring Casting Method

SiC particle-reinforced aluminum matrix composites（SiCp/Al composites）have a wide application prospect in military,electronic and automotive fields because of their excellent mechanical and physical properties.There are many methods to prepare SiC particle-reinforced Al composites,among which stir casting method is simple in process,equipment,low cost and easy for large-scale industrial production,which makes it the most promising method for manufacturing SiCp/Al composites.In this paper,15%vol SiCp/A356 composites were prepared by stir casting method,and their room temperature mechanical properties were tested by metallographic observation（OM）and scanning electron microscopy（SEM）,energy spectroscopy（EDS）and X-ray diffraction（XRD）,micro hardness tester and universal testing machine,and the effects of stirring process parameters,SiC particle pretreatment,particle size and other factors on The effects of SiC particle distribution uniformity and interfacial reaction between SiC particles and Al liquid were systematically investigated.The effects of rare earth element Sc on the organization,corrosion resistance and mechanical properties of SiCp/A356 composites during the remelting process were also investigated.The optimum preparation process parameters for the preparation of SiCp/Al composites by stir casting were:stirring temperature of 650°C,stirring speed of 200 rpm,and stirring time of 60 min.The 15%vol SiCp/A356 composites prepared under this process showed relatively uniform SiC particles and the least casting defects.The maximum tensile strength of the cast specimens reached 202.63 MPa and the elongation reached 4.73%,and the strengthening effect of SiC particles was remarkable.The remelting densification of SiCp/A356 composites by rare earth element Sc causes the eutectic Si phase in SiCp/A356 composites to change from coarse long strips or plates to fibrous ones.After the metamorphism,Si5Sc3 phase is generated at the interface with SiC particles attached to it.The mechanical properties tests showed that the increase of elemental Sc content significantly increased the maximum tensile strength and hardness of SiCp/A356 composites,and the maximum tensile strength of SiCp/A356composites reached 302.95 MPa and microhardness reached 126.5 HV when the Sc content was 0.8wt%.the elongation of SiCp/A356 composites was increased at the Sc content of The elongation of SiCp/A356 composites was maximum at 0.4 wt%of Sc content,which was 5.34%.The results of weight loss analysis and electrochemical experiments showed that the corrosion rate of SiCp/A356 composites with 0.8 wt%Sc was(0.11 v/mm·a^-1)57%lower than that of composites without Sc(0.26 v/mm·a^-1);the self-corrosion current density of composites with 0.8 wt%Sc The self-corrosion current density i_corr(8.46μA·cm^-2)of the composites with 0.8 wt%Sc was reduced by 45.3%compared to the self-corrosion current density i_corr(15.48μA·cm^-2)of the composites without the addition of Sc.46 figures,7tables and 100 references.