Effect of Y and Y2O3 on oxidation of AZ91D Mg alloys between 400 °C and 500 °C

AZ91D, AZ91D+1%Y, and AZ91D+3%Y2O3 (mass fraction) alloys were cast, and oxidized between 400 and 500 °C in air. The oxidation resistance increased in the order of AZ91D, AZ91D+3%Y2O3, and AZ91D+1%Y, indicating that Y was more effective than Y2O3 in increasing the oxidation resistance of the Mg alloys. However, all the alloys tested experienced ignition because the major oxide was MgO.