Effect of Al Content on the Corrosion Behavior of Extruded Dilute Mg–Al–Ca–Mn Alloy

The microstructure, extrusion texture and corrosion behavior of extruded dilute Mg–Al–Ca–Mn alloy with different Al contents were investigated. The corrosion rate of the alloy was more sensitive to the Fe impurities. The 1.2 wt% Al showed the lowest corrosion rate, which was mainly attributed to the weakening of the cathode effect caused by the increase of the Al and the decrease of the Fe in the precipitated phase. Refined grains, stronger basal surface texture and higher corrosion potential deriving from the higher Al content of the matrix also further enhanced the corrosion resistance of the matrix.