Effect of Nd-Rich Phases on the Corrosion Behavior of AZ80 Magnesium Alloy in Alkaline Solution

This work investigated the corrosion resistance of AZ80 (Mg-8Al-0.5Zn alloy) with different Nd contents in alkaline solution by the mass loss test, electrochemical test, scanning electron microscope, energy spectrum analysis, and x-ray diffraction. To remove the influence of the Mg 17 Al 12 phase, alloys were heat treated at 410°C for 10 h. Results revealed that Al 2 Nd and AlMnNd phases mainly exist in the alloy. The corrosion rate of the alloy increased when the Nd content was < 0.4 wt.% because the Al 2 Nd phase formed galvanic corrosion with the Mg matrix. With the increase of Nd content, AlMnNd phase appeared in the alloys, which decomposed during the corrosion process and formed a good protective film to reduce the corrosion rate.