Oxidation behaviors of Co-Al-W-0.1B superalloys in a long-term isothermal exposure at 900?C
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2018年第11期
论文作者：Yuzhi Li Zekun Yao
文章页码：2212 - 2217
摘 要：Co-Al-W-0.1B superalloys have been isothermally oxidized at 900?C for 1000,5000 and 10000 h in order to investigate their oxidation behaviors.The oxide layers and morphologies were characterized by X-ray diffraction and scanning electron microscopy combined with energy-dispersive spectroscopy.After1000 h exposure,a Co3W/γ zone,an Al2O3layer,a mixture of Co,Al,W oxides layer and a CoO layer are established on the substrate alloys.After extended oxidation,a discontinuous Al2O3layer in Co-9Al-8W-0.1B and Co-9Al-9W-0.1B alloys leads to an additional mixed oxide layer on the substrate instead of the Co3W/γ zone.The oxide layers that form on the Co-9Al-8W-0.1B and Co-9Al-9W-0.1B alloys are much thicker than those on the Co-9Al-11W-0.1B alloy,and continuously thicken during oxidation.The higher content of W is beneficial to improving the oxidation resistance as it facilitates a faster formation of Co3Was well as Al2O3.
Yuzhi Li1，Zekun Yao1
1. School of Materials Science and Engineering,Northwestern Polytechnical University
摘 要：Co-Al-W-0.1B superalloys have been isothermally oxidized at 900?C for 1000,5000 and 10000 h in order to investigate their oxidation behaviors.The oxide layers and morphologies were characterized by X-ray diffraction and scanning electron microscopy combined with energy-dispersive spectroscopy.After1000 h exposure,a Co3W/γ zone,an Al2O3layer,a mixture of Co,Al,W oxides layer and a CoO layer are established on the substrate alloys.After extended oxidation,a discontinuous Al2O3layer in Co-9Al-8W-0.1B and Co-9Al-9W-0.1B alloys leads to an additional mixed oxide layer on the substrate instead of the Co3W/γ zone.The oxide layers that form on the Co-9Al-8W-0.1B and Co-9Al-9W-0.1B alloys are much thicker than those on the Co-9Al-11W-0.1B alloy,and continuously thicken during oxidation.The higher content of W is beneficial to improving the oxidation resistance as it facilitates a faster formation of Co3Was well as Al2O3.
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