Microstructure-dependent oxidation behavior of Ni-Al single-crystal alloys
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2020年第17期
论文作者：Jianlu Pei Yefan Li Chong Li Zumin Wang Yongchang Liu Huijun Li
文章页码：162 - 171
摘 要：The effect of the γ +γ two-phase structure on the oxidation behaviors of Ni-Al single-crystal alloys at 650℃ was investigated by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X-ray diffraction and Auger electron spectroscopy. In the initial oxidation stage, the oxidation behavior is primarily determined by the growth pattern of oxides in the γ channel. The outward convex NiO was formed in unprotected wide γ channels. And Ni-Al spinel oxide provides a great number of short-circuit paths, accelerating the inward diffusion of oxygen and outward diffusion of Ni. In the late stage of oxidation, the elongated internal oxide in the large γ phase contributes to the diffusion of oxygen along the oxide/metal interface. Consequently, the Ni-Al single-crystal alloy with wide γ channels and large γ precipitates exhibited poor oxidation performance.
Jianlu Pei1，Yefan Li1，Chong Li1，Zumin Wang1，Yongchang Liu1，Huijun Li2
1. State Key Lab of Hydraulic Engineering Simulation and Safety, School of Materials Science & Engineering, Tianjin University2. School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong
摘 要：The effect of the γ +γ two-phase structure on the oxidation behaviors of Ni-Al single-crystal alloys at 650℃ was investigated by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X-ray diffraction and Auger electron spectroscopy. In the initial oxidation stage, the oxidation behavior is primarily determined by the growth pattern of oxides in the γ channel. The outward convex NiO was formed in unprotected wide γ channels. And Ni-Al spinel oxide provides a great number of short-circuit paths, accelerating the inward diffusion of oxygen and outward diffusion of Ni. In the late stage of oxidation, the elongated internal oxide in the large γ phase contributes to the diffusion of oxygen along the oxide/metal interface. Consequently, the Ni-Al single-crystal alloy with wide γ channels and large γ precipitates exhibited poor oxidation performance.
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