Structural stability and the alloying effect of TiB polymorphs in TiAl alloys

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	Structural stability and the alloying effect of TiB polymorphs in TiAl alloys
	Liu, B. G.; Liu, L. H.; Xing, W. D.; Liu, R. C.; Yang, R.; Withey, P. A.; Zhu, J.; Yu, R.; Yu, R (reprint author), Tsinghua Univ, Sch Mat Sci & Engn, Natl Ctr Electron Microscopy Beijing, Beijing 100084, Peoples R China.
刊名	ELSEVIER SCI LTD
	2017-11-01
卷号	90 页码:97-102
关键词	Titanium Aluminides Borides Structural Stability Transmission Electron Microscopy First-principles Calculations
ISSN号	0966-9795
英文摘要	Borides have been widely used in cast TiAl alloy for grain refinement and a variety of stoichiometry and crystal structure of borides were reported. Here the effects of alloying elements Nb, Ta, and Mn on the structural stability of fine boride precipitates in TiAl alloys have been studied combining transmission electron microscopy (TEM) and first-principles calculations. The results show that most boride particles have the TiB stoichiometry. In the alloy containing Nb and Mn, all the TiB particles have the B27 structure and are highly enriched with Nb but depleted with Mn. In the alloy containing Nb and Ta, however, the intergrowth of B-f and B27 structure has been observed, and the TiB particles are enriched with both Nb and Ta. First-principles calculations reveal different effects of Nb, Ta, and Mn on the structural stability of TiB polymorphs. Nb stabilizes B27 but destabilizes B-f. Ta strongly stabilizes both B27 and B-f structures. Mn strongly destabilizes both B27 and B-f structures.; Borides have been widely used in cast TiAl alloy for grain refinement and a variety of stoichiometry and crystal structure of borides were reported. Here the effects of alloying elements Nb, Ta, and Mn on the structural stability of fine boride precipitates in TiAl alloys have been studied combining transmission electron microscopy (TEM) and first-principles calculations. The results show that most boride particles have the TiB stoichiometry. In the alloy containing Nb and Mn, all the TiB particles have the B27 structure and are highly enriched with Nb but depleted with Mn. In the alloy containing Nb and Ta, however, the intergrowth of B-f and B27 structure has been observed, and the TiB particles are enriched with both Nb and Ta. First-principles calculations reveal different effects of Nb, Ta, and Mn on the structural stability of TiB polymorphs. Nb stabilizes B27 but destabilizes B-f. Ta strongly stabilizes both B27 and B-f structures. Mn strongly destabilizes both B27 and B-f structures.
学科主题	Chemistry, Physical ; Materials Science, Multidisciplinary ; Metallurgy & Metallurgical Engineering
语种	英语
资助机构	NSFC [51525102, 51390475, 51371102]; National Basic Research Program of China [2015CB654902]
公开日期	2018-01-10
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/79022]
专题	金属研究所_中国科学院金属研究所
通讯作者	Yu, R (reprint author), Tsinghua Univ, Sch Mat Sci & Engn, Natl Ctr Electron Microscopy Beijing, Beijing 100084, Peoples R China.
推荐引用方式 GB/T 7714	Liu, B. G.,Liu, L. H.,Xing, W. D.,et al. Structural stability and the alloying effect of TiB polymorphs in TiAl alloys[J]. ELSEVIER SCI LTD,2017,90:97-102.
APA	Liu, B. G..,Liu, L. H..,Xing, W. D..,Liu, R. C..,Yang, R..,...&Yu, R .(2017).Structural stability and the alloying effect of TiB polymorphs in TiAl alloys.ELSEVIER SCI LTD,90,97-102.
MLA	Liu, B. G.,et al."Structural stability and the alloying effect of TiB polymorphs in TiAl alloys".ELSEVIER SCI LTD 90(2017):97-102.