Microstructure and corrosion behaviour of Al2O3–13 wt-% TiO2 laser alloyed magnesium alloys

Nanostructured Al2O3–13 wt-% TiO2 was prepared on AZ91D magnesium alloy surface by laser surface alloying to improve its corrosion resistance. The microstructure of the laser surface alloyed specimens before and after corrosion tests was characterised by scanning electron microscope and optical microscope (OM). The phase and element composition were investigated by X-ray diffractometer and energy-dispersive spectrometry. An electrochemical workstation was used to evaluate the corrosion behaviour of the specimens. Results showed that the laser surface alloyed layer was primarily composed of Mg and Mg17Al12. Al2O3 and TiO2 existed in the form of agglomerated particles. The corrosion resistance was improved after laser surface alloying.