中文摘要：

研究了新型γ-TiAl基TiAl-3Ta-X（Cr,W）高温合金在800--900℃范围内的氧化行为。氧化增重实验及XRD，SEM分析结果表明，TiAl-3Ta-X（Cr,w）合金在800-900℃范围内氧化0--200h条件下，由Wagner的氧化经验公式计算得氧化指数n在0．976～3．849之间，氧化激活能为203kJ／mol，氧化符合线性一抛物线混合规律。试样表面形成氧化层，随着氧化温度的升高和时间的延长，氧化层厚度增加。经长时间氧化后，氧化产物由TiO2，Al2O3和AITaO4组成，Ta的中间化合物中Ta-O键的存在能有效防止合金进一步氧化。

英文摘要：

The oxidation behavior of TiA-3Ta-X（Cr, W） alloy was investigated by thermogravimetric method. Isothermal experiments were carried out from 800 ℃ to 900 ℃ in air. The alloy microstructure and the composition as well as the composition distribution of the oxide scale were analysed by scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS） and X-ray diffraction （XRD）. The results show that the oxidation kinetics obey linearity-parabolic law and the total activation energy is 203 kJ/mol at temperature range of 800-900 ℃ for 0-200 h. The scale thickness increases with the increase of time and temperature. A mixture oxide of protective A1203, A1TaO4 and TiO2 is formed for long time which becomes an important factor increasing the thermal stability of TiA1-3Ta-X （Cr, W）.