DEGENERATION PROCESS AND MECHANISM OF PRIMARY MC CARBIDES IN A CAST Ni-BASED SUPERALLOY

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	DEGENERATION PROCESS AND MECHANISM OF PRIMARY MC CARBIDES IN A CAST Ni-BASED SUPERALLOY
	Sun Wen; Qin Xuezhi; Guo Jianting; Lou Langhong; Zhou Lanzhang
通讯作者	Qin Xuezhi(xzqin@imr.ac.cn)
	2016-04-11
发表期刊	ACTA METALLURGICA SINICA
ISSN	0412-1961
卷号	52 期号:4 页码:455-462
摘要	Primary MC carbide is one of the most important phases in cast Ni-based superalloys. During long-term thermal exposure, the primary MC carbide is not stable and tends to degenerate, exhibiting various degeneration reactions, such as MC+gamma -> M6C+gamma', MC+gamma -> M6C + M23C6+gamma' and MC+gamma -> M6C + M23C6+eta. It is widely known that the degeneration of primary MC carbide has obvious influence on the microstructural evolutions of superalloys, including coarsening of gamma' phase, coarsening of grain boundaries and precipitation of topologically close packed (TCP) phase, and consequently the mechanical properties of alloys. Much research work has focused on the degeneration mechanism of primary MC carbide during long-term thermal exposure, however, it is not very clear so far. In this work, a cast Ni-based superalloy is fabricated and thermally exposed at 850 degrees C for 500 similar to 10000 h in order to study the degeneration mechanism of primary MC carbide. The degeneration of primary MC carbide is observed by OM, SEM and TEM. High-angle annular dark field (HAADF) mode of TEM is used to clearly observe the degeneration of primary MC carbide and the element distribution in the degeneration areas. The results show that the primary MC degeneration is an inter-diffusion process which occurs between the primary carbide and the gamma matrix. During the degeneration, C is released from the primary carbide, Ni, Al and Cr are provided by the gamma matrix, while Ti, W and Mo come from both primary MC and gamma matrix. The precipitation of 77 phase is determined by the atomic fraction of Ti+Nb+Ta+Hf and atomic ratio of (Ti+Nb+Ta+Hf)/Al and its amount is affected by the degeneration degree of primary MC carbide. The higher the degeneration degree, the larger the tendency for the precipitation of the eta phase.
关键词	cast Ni-based superalloy long-term thermal exposure primary MC carbide degeneration mechanism
资助者	National Natural Science Foundation of China ; National Energy Administration Program of China
收录类别	SCI
语种	英语
资助项目	National Natural Science Foundation of China[51001101] ; National Energy Administration Program of China[NY20150102]
WOS研究方向	Metallurgy & Metallurgical Engineering
WOS类目	Metallurgy & Metallurgical Engineering
WOS记录号	WOS:000374809600009
出版者	SCIENCE PRESS
引用统计	被引频次：10[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/122053
专题	中国科学院金属研究所
通讯作者	Qin Xuezhi
作者单位	Chinese Acad Sci, Inst Met Res, Shenyang 110016, Peoples R China
推荐引用方式 GB/T 7714	Sun Wen,Qin Xuezhi,Guo Jianting,et al. DEGENERATION PROCESS AND MECHANISM OF PRIMARY MC CARBIDES IN A CAST Ni-BASED SUPERALLOY[J]. ACTA METALLURGICA SINICA,2016,52(4):455-462.
APA	Sun Wen,Qin Xuezhi,Guo Jianting,Lou Langhong,&Zhou Lanzhang.(2016).DEGENERATION PROCESS AND MECHANISM OF PRIMARY MC CARBIDES IN A CAST Ni-BASED SUPERALLOY.ACTA METALLURGICA SINICA,52(4),455-462.
MLA	Sun Wen,et al."DEGENERATION PROCESS AND MECHANISM OF PRIMARY MC CARBIDES IN A CAST Ni-BASED SUPERALLOY".ACTA METALLURGICA SINICA 52.4(2016):455-462.