Effect of Mo Addition on the Oxidation Behavior of TiAl Intermetallic Compound

作者：Hiroyuki Anada, Yoshiaki Shida · 发表于：Journal of the Japan Institute of Metals and Materials · 年份：1994 · DOI：10.2320/jinstmet1952.58.7_746 · 被引用次数：13 · 研究领域：Intermetallics and Advanced Alloy Properties、Catalytic Processes in Materials Science、High-Temperature Coating Behaviors

Oxidation behavior of Mo modified Ti-34.5 mass%Al intermetallic compounds in air at 1073, 1173 and 1273 K was investigated by comparing with that of a binary Ti-34.5 mass%Al. Oxidation mass gain of the Mo-modified TiAl isothermally oxidized below 1273 K decreased with increasing Mo content. At 1273 K, however, a minimum in a mass gain-Mo content curve was observed at 2 mass%Mo content. A parabolic oxidation curve for the Mo modified TiAl was obtained under the cyclic oxidation condition at 1173 K, in contrast to a linear curve for the binary TiAl. As a result of SEM-EPMA observation, the scale of the Mo modified TiAl was found to have a layered structure in the following order from out side; TiO2/Al2O3/TiO2+Al2O3/Ti3Al (Mo enriched phase)/TiAl (matrix). Al2O3 was observed to form along the Mo enriched phase. The second Al2O3 layer from outer and the Al2O3 in the inner layer were much more continuous and must have acted as protective layers. The oxygen solid solubility decreased in the Mo modified TiAl and further in the Mo enriched phase region, which must be the cause for the external Al2O3 formation.