Isothermal oxidation behavior of Nb-bearing austenitic cast steels at 950℃

作     者：Hailong Zhao Longfei Li Qiang Feng Hailong Zhao;Longfei Li;Qiang Feng

作者机构：Beijing Advanced Innovation Center for Materials Genome EngineeringState Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083China 

出 版 物：《International Journal of Minerals,Metallurgy and Materials》 (矿物冶金与材料学报（英文版）)

年 卷 期：2022年第29卷第4期

页      面：814-824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：finacially supported by the University Research Program between Ford Motor Company and the University of Science and Technology Beijing and the Fundamental Research Funds for the Central Universities(Nos.FRF-IC-16-005 and FRF-IC-19-009) 

主　　题：austenitic cast steels isothermal oxidation primary Nb(C,N) internal oxidation Cr depletion 

摘      要：The oxidation behaviors of three austenitic cast steels with different morphologies of primary carbides at 950℃ in air were investigated using scanning electron microscopy,energy dispersive spectroscopy,and focused ion beam/transmission electron *** oxidation kinetics followed a logarithmic law,and the oxidation rate can be significantly decreased as long as a continuous silica layer formed at the scale/substrate *** the local Si concentration was inadequate,internal oxidation occurred beneath the oxide *** spallation of oxides during cooling can be inhibited with the formation of internal oxidation,owing to the reduced mismatch stress between the oxide scale and the ***“Chinese-scriptprimary Nb(C,N)was superior to the dispersed primary Nb(C,N)in suppressing the oxidation penetration in the interdendritic region by supplying a high density of quick-diffusion Cr *** addition,the innermost and outermost oxidation layers were enriched with Cr,whereas the Cr evaporation in the outermost layer was significant when the water vapor concentration in the environment was high *** findings further the understanding regarding the oxidation behavior of austenitic cast steels and will promote the alloy development for exhaust components.