Effect of SiC Particles on the Corrosion Behaviour of 6.5% SiCp/Al-Cu-Mg-Zn Composites

This study investigated the microstructure and phase composition of 6.5% SiC p /Al-Cu-Mg-Zn composites and Al-Cu-Mg-Zn alloy and measured their corrosion rates, pitting densities and maximum pit depths in 3.5 wt.% NaCl solution. Additionally, the effect of SiC particles on the microstructure and corrosion behaviour of Al-Cu-Mg-Zn alloy is discussed in detail. The results showed that the corrosion rate of 6.5% SiC p /Al-Cu-Mg-Zn composites was less than that of Al-Cu-Mg-Zn in 3.5 wt.% NaCl solution at 20 °C, 60 °C and 90 °C. The pitting density of 6.5% SiC p /Al-Cu-Mg-Zn composites was less than that of Al-Cu-Mg-Zn alloy, and the maximum pit depth of 6.5% SiC p /Al-Cu-Mg-Zn composites (approximately 360 μm in 3.5 wt.% NaCl solution at 120 °C) was smaller than that of Al-Cu-Mg-Zn alloy. The pitting power of the 6.5% SiC p /Al-Cu-Mg-Zn composites was less than that of Al-Cu-Mg-Zn alloy because precipitated S(Al 2 CuMg) and T(AlZnMgCu) were inhibited, and θ(CuAl 2 ) was refined due to the addition of SiC.