Microstructure And Interface Characterization Of Silicon Carbide Aluminum Matrix Composite With Medium And High Volume Fractions

Compared with low volume fraction SiC particle reinforced aluminum matrix composites,medium-to-high volume fraction SiC particles reinforced aluminum matrix composites are widely used in key functional structural parts in the satellite field and electronic packaging field due to the characteristics of high-performance specific strength,high-performance thermal conductivity and low-advantage thermal expansion coefficient.Now their application has developed from small size kilogram to large size tonnage with the development and progress of science and technology.Components increasingly tend to be lightweight and high-performance application development.In this paper,the different sintering processes and different volume fractions of SiC particles reinforced 6061Al matrix composites are successfully prepared by powder metallurgy.Using Optical Microscope,Scanning Electron Microscope,X-ray Diffractometer and Transmission Electron Microscope systematically study the effects of hot pressing temperature and holding time on the microstructure and interface reaction of SiCp/6061Al matrix composites and study the influence of the volume fraction of SiC particles on the structure and properties of SiCp/6061Al matrix composites at 630?hot pressing temperature and holding time for 6 hours.The experimental research results are as follows:(1)The powder metallurgy method is suitable for preparing medium-to-high volume SiC particles reinforced aluminum matrix composites.The different sintering processes and different medium and high volume fractions of SiCp/6061Al matrix composites were prepared by powder metallurgy.The producing of billets did not appear to be chipped and there were no obvious defects such as cracks on the material surface.(2)As the sintering temperature and sintering time increase for 55 vol%SiCp/6061Al matrix composites,the interface reaction between SiC and Al intensifies resulting in the brittle phase Al₄C₃as well as Mg Al₂O₄and Mg O interface products.The corrosion first begins at the interface and gradually expands to the aluminum substrate side after deionized water immersion corrosion.(3)The sintering temperature mainly affects the nucleation of Al₄C₃,while the sintering time mainly affects the growth of Al₄C3.The reaction temperature should not exceed 670?in order to avoid harmful reactions when preparing high volume fraction SiCp/6061Al matrix composites for large-size workpieces.When the reaction temperature is 650?,the holding time should not exceed 12h.When the reaction temperature is 630?,the holding time should not exceed 24h.(4)As the volume fraction of SiC particles increases,the distribution of particles becomes more denser and reunion phenomenon occurs in individual areas.But the interface is relatively flat and smooth without interface products and the interface exists in the form of mechanical bonding and chemical bonding.(5)The material density,elastic modulus and thermal conductivity gradually are increased as the volume fraction of SiC particles adds.While the bending strength and thermal expansion coefficient gradually are decreased with the augment of volume fraction of SiC particles.