Effect of friction stir processing on the corrosion behavior of pure Mg

As cast pure magnesium was friction stir processed (FSPed) by multiple passes. The treated materials were characterized by scanning electron microscope and X-ray diffraction methods. The corrosion behavior of the materials was also studied using electrochemical impedance spectroscopy. Results showed that FSP refined the structure dramatically to mean grain size value of about 1% of that of in as cast Mg. In addition, FSP dominated basal texture in the treated area of the Mg surface. The grain size was reduced and basal texture intensity increased further by repeating FSP. As a result, the corrosion resistance of the treated material improved considerably to more than 10 times of that of in as cast Mg.