Detrimental effect of cellular precipitation on the creep strength of Inconel740H |
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| Authors: | Yan Chong Zhengdong Liu Andy Godfrey Wei Liu Yuqing Weng |
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| Affiliation: | 1. Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China;2. Central Iron &3. Steel Research Institute, Beijing 100084, Chinachongyan871210@sina.com;5. Central Iron &6. Steel Research Institute, Beijing 100084, China |
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| Abstract: | Cellular precipitation (also known as discontinuous precipitation) has been observed at the grain boundaries of a newly developed nickel-based Inconel740H alloy designed for use at 700?°C in advanced ultrasupercritical coal-fired power plants. By means of element mapping and selected area diffraction, the cellular precipitates were identified as Cr-rich M23C6 carbides. The onset of cellular precipitation was found to follow a pucker mechanism in Inconel740H. The cellular precipitates at the grain boundaries, even at low volume fractions, were severely detrimental to the creep strength at 750?°C. The creep rupture life of Inconel740H containing cellular precipitates at grain boundaries was only one-tenth of that for the alloy without cellular precipitates. The reason for the drastically decreased creep rupture life is attributed to the poor resistance of cellular precipitates to crack propagation during creep. |
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| Keywords: | cellular precipitation Inconel740H ultrasupercritical creep rupture life |
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