Research On The Stir-Casting Microstructure Density Of Al-SiC Composite

Al-SiC composite has the characteristics of wear resistance,small thermal expansion coefficient and excellent thermal and electrical conductivity.It is widely used in military fields such as aerospace and advanced civil industrial fields.In order to solve the problem of high porosity of Al-SiC composite by semi-solid stirring casting,in this paper,Al-SiC composite were selected as the object of study,using the electromagnetic-mechanical stirring device to prepare semi-solid slurry,Al-SiC ingot casting by metal mold.On the premise of uniform distribution of SiC particles to study on the influence of stirring parameters on the porosity of composite and the problem of entrainment gas in stirring casting can be further solved by adjusting the process parameters.The main research contents and results are as follows:(1)On the base of the experimental research and simulated by FLUENT,when Al-SiC semi-solid slurry was stirred by the electromagnetic-mechanical stirring device,the stirring speed of the composite with porosity less than 2%and uniform distribution of SiC particles can be reduced to 100 r/min to 400 r/min.(2)Single-factor experiment was used to analyze the relationship between stirring speed,stirring time,horizontal angle of the blade,silicon carbide content and porosity.On the premise of uniform distribution of SiC particles,porosity increases with the increase of stirring speed and the extension of stirring time.However,the horizontal angle of blade and the content of silicon carbide have little effect on the porosity of the composite,and the stirring speed is the main reason for the gas entrainment of semi-solid slurry.(3)The effects of stirring speed,stirring time,blade horizontal angle and silicon carbide content on the porosity of composites were analyzed by orthogonal experiment.The optimum parameters of Al-SiC composite prepared by electromagnetic-mechanical stirring method are determined as follows:stirring speed is 100 r/min,stirring time is 10 min,SiC content is 3 vol.%,horizontal angle of blade is 20 and the porosity of the composites is the lowest at this time,which is 0.31%.