Popis: |
Magnesium alloys of AZ31, AZ31 + (0.5, 1, 1.5)wt.% CaO were cast, hot rolled, and oxidized between 450 and 650 o C in atmospheric air. The added CaO enabled to cast the AZ31 alloy in air. It decomposed and precipitated along the grain boundaries of the AZ31 alloy as Al2Ca. The more the amount of CaO was, the more Al2Ca formed. The oxidation limit was about 450 o C for the AZ31 alloy. But, It increased to 650 o C in the CaO-added alloys. Hot rolling destroyed the precipitates that formed along the grain boundaries of the AZ31 alloy. During oxidation, MgO oxide scales that incorporated CaO formed at the outer surface of the formed oxide layer. |