Macrosegregation of Zr and Mo in TC19 Titanium Alloy Ingot

doi:10.11900/0412.1961.2022.00163

IMR OpenIR

	Macrosegregation of Zr and Mo in TC19 Titanium Alloy Ingot
	Zhu Shaoxiang 1,2; Wang Qingjiang 1,2; Liu Jianrong 2; Chen Zhiyong 2
通讯作者	Wang Qingjiang(qjwang@imr.ac.cn)
	2024-07-11
发表期刊	ACTA METALLURGICA SINICA
ISSN	0412-1961
卷号	60 期号:7 页码:869-880
摘要	The alpha + ss titanium alloy TC19 (Ti-6Al-2Sn-4Zr-6Mo, mass fraction, %) has shown great application potential in aerospace because of its superior moderate-temperature mechanical properties. The bulk composition of this alloy contains Al, Sn, Zr, and Mo, which are the main alloying elements in the field of high-temperature titanium alloys. Compared with Ti, Al and Sn, which are characterized by lower melting points and densities, can be easily volatilized during vacuum arc remelting (VAR). In addition, Zr has a higher density, and Mo has a higher melting point and density compared with Ti. Therefore, control-ling the chemical homogeneity either in the macro- or micro-scale for industrial-scale titanium alloy ingot with complex compositions is challenging. In this study, the macrosegregation behavior and mechanism of Zr and Mo were investigated systematically in a TC19 industrial-scale ingot (phi 720 mm x 1160 mm) by using a directional solidification technology where samples were solidified under a constant-temperature gradient of approximately 200 degrees C/cm and a wide range of withdrawal rates (solidification rate) from 3 mm/h to 150 mm/h. Result shows an evident macrosegregation of Zr and Mo, which is primarily attributed to the difference in the solidification rate during solidification. Zr as the negative segregation element was pushed to the front of the solid-liquid interface continuously, whereas Mo as the positive segregation element was enriched in the solid phase at the solid-liquid interface. Consequently, the content of Zr is relatively lower at the center equiaxed crystal zone but higher at the top casting riser in the TC19 industrialscale ingot. However, Mo exhibits the opposite trend in comparison with Zr. The degree of element segregation decreased with the increase of the solidification rate. Moreover, the"crystal rain"caused by the density difference between liquid and solid phases as well as buoyancy would promote the macrosegregation in industrial-scale ingots. The Lorentz force arising from electromagnetic stirring is the main driving force for the flow of the molten pool during VAR. Electromagnetic stirring plays an important role in accelerating the melt flow in the molten pool, and the strong melt flow is favorable to break the correspondence between the grain structure, thereby weakening macrosegregation. Therefore, the low-temperature gradient and low solidification rate, that is, near equilibrium solidification conditions, primarily cause the macrosegregation in TC19 titanium alloy industrial-scale ingots.
关键词	TC19 titanium alloy vacuum arc remelting macrosegregation directional solidification electromagnetic stirring
DOI	10.11900/0412.1961.2022.00163
收录类别	SCI
语种	英语
WOS研究方向	Metallurgy & Metallurgical Engineering
WOS类目	Metallurgy & Metallurgical Engineering
WOS记录号	WOS:001260210800002
出版者	SCIENCE PRESS
引用统计
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/187913
专题	中国科学院金属研究所
通讯作者	Wang Qingjiang
作者单位	1.Univ Sci & Technol China, Sch Mat Sci & Engn, Shenyang 110016, Peoples R China 2.Chinese Acad Sci, Inst Met Res, Shi Changxu Innovat Ctr Adv Mat, Shenyang 110016, Peoples R China
推荐引用方式 GB/T 7714	Zhu Shaoxiang,Wang Qingjiang,Liu Jianrong,et al. Macrosegregation of Zr and Mo in TC19 Titanium Alloy Ingot[J]. ACTA METALLURGICA SINICA,2024,60(7):869-880.
APA	Zhu Shaoxiang,Wang Qingjiang,Liu Jianrong,&Chen Zhiyong.(2024).Macrosegregation of Zr and Mo in TC19 Titanium Alloy Ingot.ACTA METALLURGICA SINICA,60(7),869-880.
MLA	Zhu Shaoxiang,et al."Macrosegregation of Zr and Mo in TC19 Titanium Alloy Ingot".ACTA METALLURGICA SINICA 60.7(2024):869-880.