Oxidation behavior of Ni-based superalloy GH738 in static air between 800 and 1000℃

作     者：Jue Wang Hao Xue Ying Wang Jue Wang;Hao Xue;Ying Wang

作者机构：Jiangsu Key Laboratory of Advanced Structural Materials and Application TechnologyNanjing 211167China School of Materials Science and EngineeringNanjing Institute of TechnologyNanjing 211167China 

出 版 物：《Rare Metals》 (稀有金属（英文版）)

年 卷 期：2021年第40卷第3期

页      面：616-625页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：financially supported by the Scientific Research Fund of Nanjing Institute of Technology(No.CKJA201802) the Opening Project of Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology(No.ASMA201802) 

主　　题：GH738 Oxidation behavior Diffusion Multilayer structure 

摘      要：The oxidation behavior of a nickel-based superalloy GH738 was studied by isothermal oxidation tests in still air at different temperatures,with exposure time up to 100 ***-kinetic curves were plotted using the mass gain *** surface and cross-sectional morphologies were observed by scanning electron microscopy(SEM).A composition analysis and an oxidation-product identification were conducted using energydispersive X-ray spectroscopy(EDS) and an X-ray diffraction(XRD),*** results showed that GH738 exhibited parabolic oxidation-kinetic curves,with stable parabolic-rate constants at each *** activation energy of oxide growth was calculated to be329.6 kJ·mol^(-1).Cr_(2) O_(3)(chromia) was the external oxidation product at 800℃.A TiO_(2)-Cr_(2) O_(3) double-layer structure was formed at 900℃.The position of TiO_(2) changed from the oxide-metal interface to the air-oxide interface by the diffusion of Ti atoms in chromia during the oxidation time at this *** was observed in the Cr_(0.12)Ti_(0.78)O_(1.74)-Cr_(2) O_(3) multi-layer oxide of at 1000℃,which increased the oxidation *** all the tests,the main internal oxide was always Al_(2) O_(3).The entire GH738 oxidation process was interpreted by the competitive diffusion of elements(Cr,Ti,Ni,etc.) in metal matrix and chromia,while a schematic diagram of oxidation process was proposed.