摘要
The effect of theγ+γtwo-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 theγchannel.The outward convex NiO was formed in unprotected wideγchannels.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 largeγphase contributes to the diffusion of oxygen along the oxide/metal interface.Consequently,the Ni-Al single-crystal alloy with wideγchannels and largeγprecipitates exhibited poor oxidation performance.
基金
supported financially by the National Natural Science Foundation of China(No.51774212)。
