Oxidation behavior of Fe–Al–Cr alloy at high temperature: Experiment and a first principle study. (March 2020)

• Record Type: Journal Article
• Authors: Wang, Jintao; Liu, Shouping; Bai, Xue; Zhou, Xiaohu; Han, Xiaoxu
• Is Part Of: Vacuum. Volume 173(2020)
• Publication Date: 2020-03
• Subjects: High aluminum steel -- First-principle -- Oxidation -- Interface -- Diffusion; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2019.109144
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: Fe–Al–Cr alloys have excellent oxidation resistance at high temperature. Many studies have been carried out on their oxidation resistance mechanism, mainly on the role of Al, but there is a lack of understanding of the role of Cr. According to existing research results, the structure of the metal/oxide interface of Fe–Al–Cr alloys has been investigated by the density functional theory. Due to the third component, which is chromium, Al2 O3 films can be rapidly formed on the surface of Fe–Al–Cr alloys. Based on the density functional theory, an Fe(110)/Al2 O3 (0001) interface model was established. The Cr atoms in the alloy diffused at the Fe(110)/Al2 O3 (0001) interface and replaced the Al atoms in high temperature enviorment, resulting in the formation of a multilayer oxide (Alx Cr1-x )2 O3 . In this paper, X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Energy dispersive spectroscopy (EDS), and other experimental methods were employed to validate the multilayer oxide structure model. By calculating the interfacial bonding energy, it was concluded that the presence of Cr in Fe/Al2 O3 increases the interfacial bonding energy, but with the diffusion of Cr from the alloy matrix to the oxides, the bonding energy gradually decreases. Highlights: The existence of multilayer oxides on the surface of Fe–Al–Cr alloy has been confirmed by experiments and calculations. According to density functional theory, the formation of multilayer oxides is explained at the electronic level. At the electronic level, the effect of the diffusion of Cr on the interface system is explained.