Study on the reactivity between aluminium alloys and SiC particles.

The SiC reinforcement particles react with the molten aluminium to form Al4 C3 that is brittle and sensitive to the the humidity. This reaction degrade s the properties of the SIC reinforced aluminium matrix composites. The ext end of the reaction in the Al/SiC interface depends on the fabrication para meters such as the temperature, residence time, atmosphere and chemical com position of the aluminium matrix and the reinforcement. Systematic studies on the reactivity between the SiC particles and molten a luminium alloys have been performed, analysing the effect of the presence o f a SiO2 layer, which was formed by oxidation on the ceramic particles befo re their incorporation into the melt, as a protective barrier for preventin g the attack of the SiC. As well, the effect of the metal matrix compositio n on the interfacial reactivity has been studied employing different alumin ium alloys: AA1070 (99,7% Al), A-319.0 (Al-6Si-3Cu) and A-332.0 (Al-11Si-1, 5Cu). The composites were prepared by mixture of SiC particles (30% vol. %) , cold pressure and fusion at 900 degrees C, varying the residence time in the furnace, which simulated a cast fabrication process. The results are co mpared with. those obtained for a metal matrix composite (AA2014/SiC/13p).