Effects of Erbium Addition on the Corrosion Resistance and Microstructure of AZ91 Magnesium Alloy

The microstructures and corrosion resistance of AZ91 and AZ91+0.5 wt.% erbium (Er) magnesium alloys were studied, respectively. The results show that the Er addition in scrap AZ91 magnesium alloy can improve the corrosion resistance, markedly. The discontinuous precipitation phase (DPP) for Mg 17 Al 12 was retarded and the amount of DPP was decreased by 41% due to the formation of Al 8 ErMn 4 phase during solidification. The amount of continuous precipitation phase (CPP) in grains was decreased by 8% because of the formation of Al 7 ErMn 5 phase during solidification.