Microstructure of second-phase particles in Ti-5Al-4Sn-2Zr-1Mo-0.25Si-1Nd alloy

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	Microstructure of second-phase particles in Ti-5Al-4Sn-2Zr-1Mo-0.25Si-1Nd alloy
	G. P. Li; D. Li; Y. Y. Liu; S. X. Guan; Q. J. Wang; D. H. Ping; Z. Q. Hu
	1997
发表期刊	Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science
ISSN	1073-5623
卷号	28 期号:8 页码:1595-1605
摘要	The microstructure of second-phase, particles in the Ti-55 alloy (Ti-5Al;4Sn-2Zr-1 Mo-0.25Si-1Nd) was studied by scanning electron microscopy, transmission electron microscopy (TEM), and high-resolution electron microscopy (HREM) observations. The second-phase particles in the conventional ingot-cast Ti-55 alloy of 1 to 15 mu m in diameter and uniform distribution in matrix were observed, where the majority of these particles are elliptical. The mean free path between the particles is about 46 mu m, and the volume fraction (pct) is 2.35. The second-phase particles typically contain Nd, Sn, and O in substantial amounts, and the content of Nd is the largest in the three elements. The elements Ti, Al, Zr, Mo and Si are depleted in the particles. The second-phase particle consists of either a dark or bright matrix and some small dark blocks dispersed within the matrix. Dark blocks match SnO (orthorhombic, a = 0.500 nm, b = 0.572 nm, and c = 1.120 nm), and the matrix consists of a nanocrystalline phase with a stoichiometric Nd3Sn structure having a space group of Pm3m and lattice parameter of a = 0.344 nm. The grain size of the nanocrystalline Nd3Sn phase is about 3 to 15 nm. The melting range of the second-phase particle is estimated to be 1042 degrees C to 1600 degrees C. The microstructure bf the second-phase particles in the quenched Ti-55 alloy was also studied. Fine and uniform dispersoids (6 to 15 nm in diameter) were observed in the as-quenched state. Some lens-like particles occur at the grain boundaries, other elliptical particles appear within the grains, and some particles within the grains form rows which are parallel to the advancing liquid-solid interface. After annealing at 980 degrees C (1 to 10 hours), of the as-quenched Ti-55 alloy, coarse particles are 17 to 42 nm in average diameter, and the growth of the particles is very slow. The dispersoids in the as-annealed Ti-55 alloy are identified as nanocrystalline Nd5Sn (orthorhombic, Pnmn, a = 0.814 nm, b = 1.732 nm, and c = 0.814 nm) intermetallic compound, and the interface between the Nd5Sn4 phase and the matrix is a typical high-angle grain boundary.
部门归属	chinese acad sci,inst met res,atom imaging solids lab,shenyang 110015,peoples r china.;li, gp (reprint author), chinese acad sci,inst met res,dept titanium alloys,shenyang 110015,peoples r china
关键词	Strengthened Titanium-alloys Rapid Solidification Nanocrystalline Materials
URL	查看原文
WOS记录号	WOS:A1997XR03300001
引用统计	被引频次：21[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/321006/37993
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	G. P. Li,D. Li,Y. Y. Liu,et al. Microstructure of second-phase particles in Ti-5Al-4Sn-2Zr-1Mo-0.25Si-1Nd alloy[J]. Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science,1997,28(8):1595-1605.
APA	G. P. Li.,D. Li.,Y. Y. Liu.,S. X. Guan.,Q. J. Wang.,...&Z. Q. Hu.(1997).Microstructure of second-phase particles in Ti-5Al-4Sn-2Zr-1Mo-0.25Si-1Nd alloy.Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science,28(8),1595-1605.
MLA	G. P. Li,et al."Microstructure of second-phase particles in Ti-5Al-4Sn-2Zr-1Mo-0.25Si-1Nd alloy".Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science 28.8(1997):1595-1605.