First-principles studies of the influences mechanism of Y, Hf elements on the high temperature oxidation of γ-TiAl alloys

1st International Conference on New Material and Chemical Industry

材料科学;化学工业

Zhang, G.Y.^1 ; Liu, C.M.^2 ; Fang, G.L.^1

College of Physics Science and Technology, Shenyang Normal University, Shenyang

110034, China^1

School of Materials and Metallurgy, Northeastern University, Shenyang

110809, China^2

关键词: Covalent interactions;    Electron structures;    First-principles study;    Gamma tial alloys;    Influence mechanism;    Initial oxidation;    Plane-wave pseudopotential method;    Surface active elements;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/167/1/012049/pdf
DOI  :  10.1088/1757-899X/167/1/012049

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

The influences mechanisms of Y, Hf elements on the high temperature oxidation of γ-TiAl alloys were studied by using a first-principle plane wave pseudopotential method within the density functional theory. It is shown that Y, Hf atoms segregate to the γ-TiAl surface by substituting Ti atoms, and Y atom is easier to segregate than Hf. Y, Hf atoms segregated at γ-TiAl surface decrease the adhesion of O and γ-TiAl surface, which decreases the oxidation rate of γ-TiAl alloys and thereby hinders the growth of oxide films. The electron structure calculations suggest that the interaction between O and Ti, Al, Y, Hf atom exists both ionic and covalent binding characteristics, the decrease of the adhesion of O and γ-TiAl surface with the doped Y, Hf is mainly attributed to the weaken covalent interactions. As a result, the results obtained by first principles can make us get a deeper understanding of the mechanism of the segregation of Y, Hf to the γ-TiAl surface and the influence mechanism of surface active elements Y, Hf on the initial oxidation of γ-TiAl alloys.