CAJ | 학술논문

用热重法研究稀土元素Y和Ce对定向凝固镍基高温合金 DZ444高温氧化行为的影响，用X 射线衍射仪和扫描电镜等观察和分析氧化膜组成和形貌。结果表明：合金在700、850和950℃下的恒温氧化动力学均符合抛物线规律，稀土元素的添加对其无影响；然而，添加稀土元素使其氧化激活能由257.6 kJ/mol 降低至246.8 kJ/mol；DZ444合金氧化膜分为3层：外层为疏松的 Cr2O3、TiO2和(Cr0.88Ti0.12)2O3的混合物；中间层为Cr2O3；内氧化物层为 Al2O3。稀土元素未改变合金氧化膜的组成。稀土元素极易偏聚在合金表面，促进保护性 Cr2O3膜的形成，从而阻止合金的进一步氧化，并能有效抑制合金的内氧化。
용열중법연구희토원소Y화Ce대정향응고얼기고온합금 DZ444고온양화행위적영향，용X 사선연사의화소묘전경등관찰화분석양화막조성화형모。결과표명：합금재700、850화950℃하적항온양화동역학균부합포물선규률，희토원소적첨가대기무영향；연이，첨가희토원소사기양화격활능유257.6 kJ/mol 강저지246.8 kJ/mol；DZ444합금양화막분위3층：외층위소송적 Cr2O3、TiO2화(Cr0.88Ti0.12)2O3적혼합물；중간층위Cr2O3；내양화물층위 Al2O3。희토원소미개변합금양화막적조성。희토원소겁역편취재합금표면，촉진보호성 Cr2O3막적형성，종이조지합금적진일보양화，병능유효억제합금적내양화。
The effect of rare earth elements Y and Ce on the oxidation behavior of Ni-based superalloy DZ444 at elevated temperatures was studied by TGA method. The composition and morphology of the oxide films of DZ444 alloy were measured by XRD and SEM. The results indicate that rare earth elements has no effect on the oxidation kinetics, which obey parabolic law at 700, 850 and 950 ℃. However, the values of activation energy decrease from 257.6 kJ/mol to 246.8 kJ/mol when Y and Ce elements are added to the alloy. The oxide films of DZ444 alloy consist of three layers, loose upper layer consists of TiO2, Cr2O3 and (Cr0.88Ti0.12)2O3, compact intermediate layer is mainly Cr2O3, and discrete internal oxides are Al2O3. The composition of oxide films is not changed by rare earth elements, which can easily segregate on the surface of the alloy and accelerate the formation of protective oxidation film to prevent further oxidation. Therefore, it can be concluded that the addition of rare earth elements Y and Ce can effectively inhibit the development of internal oxidation.