Preparation And Properties Of Magnesium Aluminium Matrix Composites Reinforced With Silicon Carbon Particles

The magnesium aluminium matrix composites have greater potential applications thantraditional metal materials in the new technological fields, owing to the excellent specificstrength, stiffness and casting ability. But the original preparing technology of metal matrixcomposites can’t be used in the preparation of the magnesium aluminium matrix composites,because the magnesium aluminium alloy have the characteristics of low melting point, highchemical reactivity and easily being burned and oxidated.In this paper, magnesium aluminium alloy reinforced by silicon carbon particles with thesize range of1⁶μm, has been fabricated through employing flux protection.By the scanning electron microscopy and optical microscopy, it was observed that fluxprotection process has been successfully utilized to synthesize SiC particles reinforced Mg-Almatrix composites, SiC particles are distributed uniformly. The optimum preparationconditions is compound temperature760℃, holding temperature420℃, holding time6h, theaddition amount of SiC particles2wt.%. The pretreatment methods of SiC particles isoxidated8h at900℃.The phase constitute analysis of composites by employing X-ray diffraction show thatthere was a reaction in the interface, the presences of Mg₂Si and the fragility phase Al₄C₃were observed in the composites. The addition of SiC particles can refine the microstructureof Mg-Al matrix, which is due to the reaction of SiC with Mg-Al alloy.The composites show a mixed ductile and brittle fracture feature. The results from theproperties of magnesium aluminium matrix composites reinforced with silicon carbonparticles show that the hardness and density of composites increase, the tensile strength andyield strength increase first and then decrease, the elongation and the conductivity ofcomposites tend to gradually decrease and the wear properties of the composites tend to enhance with the increase of SiC particles addition amount. Under the optimum preparationconditions, the stationary of the friction coefficient and chemical corrosion protection of thecomposites are the best, the grain size reached the minimum, and the tensile strength and yieldstrength reached the maximum value.