Isothermal oxidation behavior of TiAl intermetallics with different oxygen contents
(1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
3. Department of Modern Mechanics, University of Science & Technology of China, Hefei 230027, China)
2. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
3. Department of Modern Mechanics, University of Science & Technology of China, Hefei 230027, China)
Abstract: Isothermal oxidation behaviors of Ti-45Al-2Fe-2Mo-1Cr intermetallics with different oxygen contents were studied under the condition of 950 °C, 100 h in air, and the oxidation kinetic parameters were also evaluated. The results show that the oxidation resistance of the TiAl intermetallics is negatively related to the oxygen content, and both the mass gain and thickness of oxide scale increase with the oxygen content. The sub-surface microstructure of the oxide scales varies with the oxygen content. Z phase is observed in the sub-surface area of the low-oxygen-content alloy, while the τ2(Al2FeTi) phase is found in the medium-oxygen-content and the high-oxygen-content alloys. The deterioration of oxidation resistance is due to the enhanced internal oxidation with the increase of oxygen content. It is possible to improve the oxidation resistance by controlling the oxygen content.
Key words: TiAl intermetallics; oxygen content; isothermal oxidation; oxidation kinetic