Influence of Re on the Properties of a NiCoCrAlY Coating Alloy
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2011年第5期
论文作者：M.S. Dargusch
文章页码：408 - 414
摘 要：MCrAlY can serve as stand-alone overlay coatings or bond coats in thermal barrier coating systems, and its properties play a vital role in determining the performance of these coating systems. In order to further understand the behavior of MCrAlY coatings, several NiCoCrAlY model alloys with different levels of Re （0.3 wt%, 6 wt%, and 9 wt%） were investigated. Microstructural observation showed the addition of Re promoted the precipitation of Cr-rich phases, such as α-Cr and σ. The presence of α-Cr lowered the coecient of thermal expansion （CTE） of the coating alloys, which could reduce the CTE mismatch at the scale-metal interface. The solid solution strengthening effect of Re is responsible for an increase in Rockwell hardness of the coating alloys. But the isothermal oxidation resistance at 1100oC was deteriorated due to the precipitation of brittle α-Cr phase, a phase of inferior oxidation resistance compared with β-NiAl and γ-Ni.
M.S. Dargusch
School of Materials & Mining Engineering,The University of Queensland
摘 要：MCrAlY can serve as stand-alone overlay coatings or bond coats in thermal barrier coating systems, and its properties play a vital role in determining the performance of these coating systems. In order to further understand the behavior of MCrAlY coatings, several NiCoCrAlY model alloys with different levels of Re （0.3 wt%, 6 wt%, and 9 wt%） were investigated. Microstructural observation showed the addition of Re promoted the precipitation of Cr-rich phases, such as α-Cr and σ. The presence of α-Cr lowered the coecient of thermal expansion （CTE） of the coating alloys, which could reduce the CTE mismatch at the scale-metal interface. The solid solution strengthening effect of Re is responsible for an increase in Rockwell hardness of the coating alloys. But the isothermal oxidation resistance at 1100oC was deteriorated due to the precipitation of brittle α-Cr phase, a phase of inferior oxidation resistance compared with β-NiAl and γ-Ni.
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