Control of precipitation behaviour of Hastelloy-X through grain boundary engineering |
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| Authors: | Xiaoyan Wang Kentaro Kurosawa Ming Huang Xianke Lu Dao Zhang Hiroyuki Kokawa |
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| Affiliation: | 1. School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, People’s Republic of China;2. Department of Materials Processing, Graduate School of Engineering, Tohoku University, Sendai, Japan |
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| Abstract: | Grain boundary engineering (GBE) was employed to control the precipitation behaviour of Hastelloy-X alloy. The precipitate characteristics and thermal stability of grain boundary character distribution (GBCD) were investigated by aging at 850°C. M6C carbides and µ phases were observed in the matrix and on grain boundaries, respectively. It revealed that the formation of µ phase was closely related to the grain boundary structure. GBCD effectively suppressed the nucleation and coarsening of µ phases on the grain boundaries. Owing to the Mo depletion in the vicinity of random grain boundary, the formation of the precipitates was inhibited on the adjacent grain boundaries. The thermal stability of the GBE-optimised microstructure was confirmed at 850°C for 720?h without significant microstructural degradation. |
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| Keywords: | Nickel-based superalloy aging precipitation Mo enrichment grain boundary character distribution thermal stability |
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