Effect of yttrium addition and the powder size on oxide film and powder ignition temperature of AZ91D magnesium alloy

This paper focused on the influence of yttrium (Y) addition and powder size (diameter) on the oxide film and powder ignition temperature of AZ91D alloy. Y addition in the alloy fell into 6 categories, namely 0 wt.%, 0,15 wt.%, 0.28 wt.%, 0.45 wt.%, 0.60 wt.% and 1.0 wt.%. The powders of 58 mu m, 75 mu m, 106 mu m, 120 mu m, 150 mu m, 200 mu m and 270 mu m in diameter were used for analysis of the influence of powder size on oxidation resistance of alloy powders. During oxidation test, powder size had limited influence on the ignition temperature of the alloy powders. The specific area and inter-space of the powders showed opposite effect on the ignition temperature of the alloy. With increasing Y addition, the tightness of oxide film increased, thus ignition temperature increased, obtaining peak magnitude at 0.28 wt.% Y addition. And then, it began to decrease with further increasing Y addition to 1.0 wt.%. (C) 2009 Elsevier B.V. All rights reserved.