Corrosion - Fatigue Performance of Magnesium Alloys

Abstract

To determine the effect of a coating on fatigue strength, three point bend fatigue tests of coated and un-coated AM50 and AZ91D magnesium high pressure die cast specimens were made and S-N curves determined. Environments used were air, tap water and natural seawater. A difference in corrosion fatigue performance has been found, between AZ91D and AM50 and for both alloys performance in air was superior to both water environments. AZ91D has better corrosion fatigue resistance in tap water than in seawater; conversely, AM50 has better corrosion fatigue resistance in seawater than tap water. The results showed that the fatigue life was not reduced in these water environments for coated specimens, as the coating usually provided protection from corrosion.