Atmospheric corrosion behavior of field-exposed magnesium alloys: Influences of chemical composition and microstructure

Ten kinds of magnesium alloys with various chemical compositions and/or microstructures were exposed to actual atmospheric environments for three years, and the influences of chemical compositions and microstructures on atmospheric corrosion behavior of magnesium alloys were investigated. The results showed that the atmospheric corrosion resistance of magnesium alloys generally increased with the Al content in the alloys, but intermetallic phases had a considerable influence on the corrosion resistance. Grain refinement improved the corrosion resistance of magnesium alloys. It was also found that atmospheric corrosion rate increased with exposure time, and this phenomenon was explained in the present work.