Effect of grain boundary precipitates on the stress rupture properties of K4750 alloy after long-term aging at 750 degrees C for 8000 h

doi:10.1016/j.jmst.2021.03.022

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	Effect of grain boundary precipitates on the stress rupture properties of K4750 alloy after long-term aging at 750 degrees C for 8000 h
	Ou, Meiqiong 1; Ma, Yingche 1; Hou, Kunlei 1,2; Wang, Min 1; Ma, Guangcai 1; Liu, Kui 1
刊名	JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
	2021-11-30
卷号	92 页码:11-20
关键词	Ni-base superalloy Long-term aging, MC carbide eta phase Stress rupture properties Residual strain distribution
ISSN号	1005-0302
DOI	10.1016/j.jmst.2021.03.022
通讯作者	Ma, Yingche(ycma@imr.ac.cn) ; Liu, Kui(kliu@imr.ac.cn)
英文摘要	In K4750 alloy, the evolution of grain boundary (GB) precipitates, including the degradation of blocky MC carbide particles and the precipitation of granular/needle-like eta phase particles, were observed after long-term aging (LA) at 750 degrees C for 8000 h. During MC degradation, the Ti and C released from the MC carbide combined with Ni and Cr, respectively, in the gamma matrix to form eta-Ni3Ti phase and Cr-rich M23C6 carbide. Large amounts of granular eta phase precipitated at GBs and the needle-like eta phase grew gradually from GBs toward the grain interior. Because of the growth of the eta phase through absorbing gamma' phase, gamma'-depleted zones were formed around the eta phase. The evolution of the MC carbide and eta phase was primarily responsible for the decrease of the stress rupture life and the increase of elongation. After an LA sample was tested at 750 degrees C and 360 MPa, the residual strain distribution was investigated by electron backscatter diffraction (EBSD). The results showed that the residual strain mainly distributed at GBs, especially in the region of MC degradation and at the edges of eta phases, which was closely related to the appearance of phase interfaces. Microvoids/cracks easily initiated at phase interfaces, then easily extended along the gamma'-depleted zones, thus the stress rupture life of LA samples was substantially shorter than that of samples subjected to the standard treatment. In particular, because of large amounts of fine degraded MC, granular M23C6 and granular eta phase particles distributed at GBs after 750 degrees C/8000 h LA and microvoid/crack formation could be hindered by the formation of dimples, which led to an increase of elongation. (C) 2021 Published by Elsevier Ltd on behalf of Chinese Society for Metals.
资助项目	National Natural Science Foundation of China[52001314] ; Natural ScienceFoundation of Liaoning Province of China[2020-BS-0 08] ; China Postdoctoral Science Foundation[2020M671403]
WOS研究方向	Materials Science ; Metallurgy & Metallurgical Engineering
语种	英语
出版者	JOURNAL MATER SCI TECHNOL
WOS记录号	WOS:000718790900002
资助机构	National Natural Science Foundation of China ; Natural ScienceFoundation of Liaoning Province of China ; China Postdoctoral Science Foundation
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/167374]
专题	金属研究所_中国科学院金属研究所
通讯作者	Ma, Yingche; Liu, Kui
作者单位	1.Chinese Acad Sci, Shi Changxu Innovat Ctr Adv Mat, Inst Met Res, Shenyang 110016, Peoples R China 2.Univ Sci & Technol China, Sch Mat Sci & Engn, Hefei 230026, Peoples R China
推荐引用方式 GB/T 7714	Ou, Meiqiong,Ma, Yingche,Hou, Kunlei,et al. Effect of grain boundary precipitates on the stress rupture properties of K4750 alloy after long-term aging at 750 degrees C for 8000 h[J]. JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY,2021,92:11-20.
APA	Ou, Meiqiong,Ma, Yingche,Hou, Kunlei,Wang, Min,Ma, Guangcai,&Liu, Kui.(2021).Effect of grain boundary precipitates on the stress rupture properties of K4750 alloy after long-term aging at 750 degrees C for 8000 h.JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY,92,11-20.
MLA	Ou, Meiqiong,et al."Effect of grain boundary precipitates on the stress rupture properties of K4750 alloy after long-term aging at 750 degrees C for 8000 h".JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY 92(2021):11-20.