Effect of Cooling Rate on Boride and Room Temperature Tensile Properties of beta-Solidifying gamma-TiAl Alloys

doi:10.11900/0412.1961.2019.00100

IMR OpenIR

	Effect of Cooling Rate on Boride and Room Temperature Tensile Properties of beta-Solidifying gamma-TiAl Alloys
	Wang Xi 1,2; Liu Renci 1; Cao Ruxin 3; Jia Qing 1; Cui Yuyou 1; Yang Rui 1
通讯作者	Liu Renci(rcliu@imr.ac.cn)
	2020-02-11
发表期刊	ACTA METALLURGICA SINICA
ISSN	0412-1961
卷号	56 期号:2 页码:203-211
摘要	beta-solidifying gamma-TiAl alloys have attracted much attention for their higher specific strength and better mechanical properties at elevated temperature. They usually need some boron addition to refine the lamellar grain size, which is believed to improve their poor room temperature ductility. However, the boron addition may cause some side effects on mechanical properties for the formation of borides with unfavorable morphology and crystal structure, which is severely influenced by the alloy composition and cooling rate during casting. The components of gamma-TiAl applied usually have complex structure, such as different thicknesses, which leads to different cooling rates and therefore different microstructures and mechanical properties. To evaluate the influence of cooling rate on the microstructure and mechanical properties of gamma-TiAl investment casting, plate with step thicknesses was designed to achieve different cooling rates. Step plates of beta-solidifying boron-containing TiAl alloy were fabricated by centrifugal casting in Y2O3 facing coating ceramic moulds. It was found that boride mainly distributed on grain boundary, and its aspect ratio increased with increasing cooling rate, with its morphology varying from short, flat plate to long, curvy ribbon. The short plate and curvy ribbon borides were TiB with B27 and B structure, respectively. Both types of boride exhibit anisotropic growth characteristics (especially for B, structure), with the slowest growth rate along [100] and [010] for B27 structure and B, structure, respectively. This is attributed to the difficulty of atomic rearrangement along corresponding directions during solidification. The cooling rate increase caused the increase of yield strength but the decrease of room temperature ductility, the former results from the decreasing of grain size and lamellar spacing, while the latter results from the easy cracking nucleation and propagation of the long curvy boride, leaving smooth curvy surfaces on the fracture surface. Samples containing short flat plate boride showed better ductility, and no smooth curvy surface was observed.
关键词	gamma-TiAl alloy beta-solidifying investment casting cooling rate boride tensile property
资助者	National Natural Science Foundation of China ; National Key Research and Development Program of China
DOI	10.11900/0412.1961.2019.00100
收录类别	SCI
语种	英语
资助项目	National Natural Science Foundation of China[51701209] ; National Key Research and Development Program of China[2016YFB0701304] ; National Key Research and Development Program of China[2016YFB0701305]
WOS研究方向	Metallurgy & Metallurgical Engineering
WOS类目	Metallurgy & Metallurgical Engineering
WOS记录号	WOS:000507327100008
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/321006/136749
专题	中国科学院金属研究所
通讯作者	Liu Renci
作者单位	1.Chinese Acad Sci, Inst Met Res, Shenyang 110016, Peoples R China 2.Univ Sci & Technol China, Coll Mat Sci & Engn, Shenyang 110016, Peoples R China 3.China Three Gorges Univ, Coll Mech & Power Engn, Yichang 443002, Peoples R China
推荐引用方式 GB/T 7714	Wang Xi,Liu Renci,Cao Ruxin,et al. Effect of Cooling Rate on Boride and Room Temperature Tensile Properties of beta-Solidifying gamma-TiAl Alloys[J]. ACTA METALLURGICA SINICA,2020,56(2):203-211.
APA	Wang Xi,Liu Renci,Cao Ruxin,Jia Qing,Cui Yuyou,&Yang Rui.(2020).Effect of Cooling Rate on Boride and Room Temperature Tensile Properties of beta-Solidifying gamma-TiAl Alloys.ACTA METALLURGICA SINICA,56(2),203-211.
MLA	Wang Xi,et al."Effect of Cooling Rate on Boride and Room Temperature Tensile Properties of beta-Solidifying gamma-TiAl Alloys".ACTA METALLURGICA SINICA 56.2(2020):203-211.