Abstract: The pit morphology of SiCp/2024 Al metal matrix composites (MMCs) in 3.5% NaCl solution was investigated by scanning electron microscopy and compared with that of corresponding unreinforced matrix alloy. The results show that the pit morphology depends on the volume fraction and size of SiC particles. The pits on the MMCs are more numerous and smaller in size as the volume fraction increases or particle size is reduced. And, the pits are a little bigger, less numerous and more non-uniform in spatial distribution when compared with those on the 2024 Al. Moreover, severe local corrosion occurs on the MMCs except the one reinforced by 30% SiC volume fraction. The corrosion mechanism of the MMCs is galvanic corrosion between the phase rich in Cu and the matrix, and between the SiC particle and the matrix.