Influence of particle size distribution on properties of SiC particles reinforced aluminum matrix composites with high SiC particle content

摘要

In this paper, 60.5-68.0 vol.% SiCp/AI composites were prepared by infiltrating liquid aluminum into preforms. The average diameters of Si[ particles used in the particles packing experiments were 45, 8 and 2 pm for the group 1 preforms, and 75, 8 and 2 mu m for the group II preforms. The thermal-mechanical properties of the composites were investigated. The mechanical properties test showed that the tensile strength of the composites was in the range of 212349 MPa, and the elastic modulus of the composites was greater than 150 GPa. For a given SiC volume fraction, the tensile strength and elastic modulus of the group 1 composites were greater than that of the group II composites. The thermal properties test revealed that the coefficient of thermal expansion of the composites was in the range of 10.33-12.32 x 10(-6)/degrees C, and the measured thermal conductivity of the composites was greater than 85.6 Wi(nn.degrees C). The change of the particle size distribution had no effect on the coefficient of thermal expansion, and the coefficient of thermal expansion decreased linearly with the increase of SiC content. An average diameter approach for estimating the thermal conductivity of the composites was proposed in the application of Hasselmn-Johnson model. The results indicated that the predictions of the model were in good agreement with the measured thermal conductivity of the composites.