Fabrication of oxidized sic particles reinforced aluminum matrix composite by pressureless infiltration technique

The oxidation behavior of SiC particles in the temperature range from 1000°C to 1200°C was investigated. The dependence of weight gain and oxidation time was parabolic and the oxidation behavior was controlled by diffusion process, with a oxidation activation energy of 219 kJ/mol. Using oxidized SiC particles as reinforcement and aluminum alloy containing Si and Mg as matrix, a SiC _p/Al composite was fabricated by pressureless infiltration technique. The microstructure and interfacial morphology were analyzed and the pressureless infiltration mechanisms were discussed. The particles were distributed uniformly in the composite, without particles agglomeration. Interfacial reactions were found in the composite and the product was identified as MgAl ₂O ₄, formed by the reactions between surface oxide layer of SiC particles and Mg, Al in the matrix. The interfacial reactions enhanced the wettability and promoted the spontaneous infiltration process.