(中南大学 材料科学与工程学院， 长沙 410083)
摘 要: 采用静态恒温氧化增质法研究Ni76Cr19AlTi合金在600~800 ℃范围内的高温氧化动力学规律， 采用场发射扫描电镜对氧化产物进行表面和横断面形貌观察， 用X射线衍射仪分析氧化膜层的物相组成。 结果表明， 合金在600~800 ℃范围内氧化增质与氧化时间的关系遵从抛物线规律， 氧化速率常数Kp随温度的升高而增大； 在800 ℃下氧化200 h， 平均氧化速率为0.002 15 mg·cm-2·h-1， 合金属于完全抗氧化级； 氧化过程中， 氧化膜主要受控于Cr2O3的生长， 经过长时间氧化后， 表层为比较疏松的TiO2和Cr2O3， 内层为起保护作用的Cr2O3和Al2O3， 氧化膜的组成以Cr2O3为主。
关键字: Ni76Cr19AlTi合金； 镍基合金； 高温氧化； 氧化动力学
（School of Material Science and Engineering, Central South University,Changsha 410083, China）
Abstract: The oxidation kinetics of Ni76Cr19AlTi superalloy in air from 600 ℃ to 800 ℃ was studied by using TGA method. The composition, phase structure and morphologies of oxides formed under different conditions were observed and analyzed. The results show that the oxidization kinetics of the alloy follows the parabolic rate law in the range of 600-800 ℃, the oxidization rate constant Kp increases as temperature elevating. The average oxidization rate at 800 ℃ for 200 h is 0.002 15 mg·cm-2·h-1, showing the oxidization resistance of the alloy is the first grade. During oxidation, the oxidation film mainly consists of Cr2O3 and the growth of the oxidation film is mainly controlled by Cr2O3. After oxidizing for a long time, the oxidation film becomes loose, in which the upper layer consists of TiO2 and Cr2O3, but internal protective layer consists of Cr2O3 and Al2O3.
Key words: Ni76Cr19AlTi superalloy; nickel-based superalloy; high temperature oxidation; oxidation kinetics
