(中南大學 材料科學與工程學院， 長沙 410083)
摘 要: 采用靜態(tài)恒溫氧化增質(zhì)法研究Ni76Cr19AlTi合金在600~800 ℃范圍內(nèi)的高溫氧化動力學規(guī)律， 采用場發(fā)射掃描電鏡對氧化產(chǎn)物進行表面和橫斷面形貌觀察， 用X射線衍射儀分析氧化膜層的物相組成。 結果表明， 合金在600~800 ℃范圍內(nèi)氧化增質(zhì)與氧化時間的關系遵從拋物線規(guī)律， 氧化速率常數(shù)Kp隨溫度的升高而增大； 在800 ℃下氧化200 h， 平均氧化速率為0.002 15 mg·cm-2·h-1， 合金屬于完全抗氧化級； 氧化過程中， 氧化膜主要受控于Cr2O3的生長， 經(jīng)過長時間氧化后， 表層為比較疏松的TiO2和Cr2O3， 內(nèi)層為起保護作用的Cr2O3和Al2O3， 氧化膜的組成以Cr2O3為主。
關鍵字: Ni76Cr19AlTi合金； 鎳基合金； 高溫氧化； 氧化動力學
（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
