A new refractory Ni7Nb2 phase identified in Laves eutectic regions by TEM study

doi:10.1016/j.actamat.2021.116985

CORC > 金属研究所 > 中国科学院金属研究所

	A new refractory Ni7Nb2 phase identified in Laves eutectic regions by TEM study
	Ge, Hualong 1,2; Xing, Weiwei 3; Chen, Bo 3; Hu, Xiaobing 4; Zheng, Shijian 1,5; Liu, Kui 3; Ma, Xiuliang 1
刊名	ACTA MATERIALIA
	2021-08-01
卷号	214 页码:10
关键词	Nickel-based superalloys Inconel 718 In-situ transmission electron microscopy Laves phase Eutectic Ni-Nb phase
ISSN号	1359-6454
DOI	10.1016/j.actamat.2021.116985
通讯作者	Zheng, Shijian(sjzheng@hebut.edu.cn)
英文摘要	The dissolution behavior of gamma/Laves eutectic within a typical Ni-based superalloy (Inconel 718) was investigated by in-situ and conventional transmission electron microscopy (TEM) techniques. The results show that the Laves phase dissolved firstly at 700 degrees C, but a new Ni7Nb2 phase possessing similar composition with delta-Ni3Nb phase precipitated near Laves phase did not dissolve at temperatures up to 950 degrees C. The new Ni7Nb2 phase with lattice parameters: a=0.473 nm, b=0.794 nm, c=1.21 nm and beta=91.3 degrees, shows a C2/m space group symmetry. The crystal structure of the new Ni7Nb2 phase can be understood by "triple layers" as the Ni7Zr2-type structure does, stacking perpendicular to the (001) planes. Instead of stacking with one single shift vector s corresponding to the Ni7Zr2-type structure, the stacking sequences of the new Ni7Nb2 can be characterized by alternate occurrence of +s and -s. Moreover, the structural change of gamma/Laves eutectic constituent before and after heat treatment was investigated. The Ni7Nb2 could remain after heat treatment. Since the experimental Ni7Nb2 structure was shown to be unstable in the Ni-Nb binary system by calculation, it is suggested that Zr, Si and Co promote the formation of Ni7Nb2 phase in superalloys according to the segregation behaviors of elements. Moreover, as Ni7Zr2 is considered to be detrimental to the mechanical properties, Ni7Nb2 phase should also have negative influences and should be eliminated through possible approaches. The finding of the new phase should shed light on the microstructural controlling and heat treatment process formulating of superalloys. (C) 2021 Acta MaterialiaInc. Published by Elsevier Ltd. All rights reserved.
资助项目	National Natural Science Foundation of China[51771201] ; Key Project of Natural ScienceFoundation of Liaoning Province, China[20180510059]
WOS研究方向	Materials Science ; Metallurgy & Metallurgical Engineering
语种	英语
出版者	PERGAMON-ELSEVIER SCIENCE LTD
WOS记录号	WOS:000670363500010
资助机构	National Natural Science Foundation of China ; Key Project of Natural ScienceFoundation of Liaoning Province, China
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/159932]
专题	金属研究所_中国科学院金属研究所
通讯作者	Zheng, Shijian
作者单位	1.Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang 110016, Peoples R China 2.Univ Sci & Technol China, Sch Mat Sci & Engn, Hefei 230026, Peoples R China 3.Chinese Acad Sci, Inst Met Res, Shenyang 110016, Peoples R China 4.Northwestern Univ Evanston, Dept Mat Sci & Engn, Evanston, IL 60208 USA 5.Hebei Univ Technol, Sch Mat Sci & Engn, Tianjin Key Lab Mat Laminating Fabricat & Interfa, Tianjin 300130, Peoples R China
推荐引用方式 GB/T 7714	Ge, Hualong,Xing, Weiwei,Chen, Bo,et al. A new refractory Ni7Nb2 phase identified in Laves eutectic regions by TEM study[J]. ACTA MATERIALIA,2021,214:10.
APA	Ge, Hualong.,Xing, Weiwei.,Chen, Bo.,Hu, Xiaobing.,Zheng, Shijian.,...&Ma, Xiuliang.(2021).A new refractory Ni7Nb2 phase identified in Laves eutectic regions by TEM study.ACTA MATERIALIA,214,10.
MLA	Ge, Hualong,et al."A new refractory Ni7Nb2 phase identified in Laves eutectic regions by TEM study".ACTA MATERIALIA 214(2021):10.