Effect of Microstructures and Textures on Different Surfaces on Corrosion Behavior of an as-Extruded ATZ411 Magnesium Alloy Sheet

The effect of textures on different surfaces of an as-extruded Mg-4 Al-1 Sn-1 Zn(ATZ411) alloy sheet on its corrosion behavior was systematically investigated. The microstructure was examined by optical/scanning electron microscopy. The texture was characterized by X-ray diffraction and electron backscatter diffraction. The corrosion performance was evaluated by immersion tests, electrochemical measurements, and corrosion morphology observation. The results showed that there were obvious differences in the corrosion morphology and corrosion resistance on different surfaces. The surface perpendicular to extrusion direction had better corrosion resistance and more uniform corrosion damage than that perpendicular to the normal direction and that perpendicular to the transverse direction in 3.5 wt% NaCl solution. The corrosion morphology was mainly determined by the distribution of the second phase and fine-grained regions. The corrosion rate was more related to the overall texture.