Evidence of the existence an alpha/beta interface phase in a near-alpha titanium alloy

IMR OpenIR

	Evidence of the existence an alpha/beta interface phase in a near-alpha titanium alloy; Evidence of the existence an alpha/beta interface phase in a near-alpha titanium alloy
	Q. Kang; Z. X. Guo; D. Li; Y. Y. Liu
	2000 ; 2000
发表期刊	Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing ; Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing
ISSN	0921-5093 ; 0921-5093
卷号	280 期号:1 页码:182-186
摘要	There have been contradictory reports about the existence of an alpha/beta interface phase in titanium alloys over the last two decades. Recently some publications tend to Favour the notion that the interface phase is an artifact formed in the preparation of the thin foil by electropolishing. However our studies on an advanced near-alpha titanium alloy (Ti-5.5Al-3.98Sn-2.16Zr-0.95Mo-0.85Nd-0.28Si) especially by means of High Resolution Transmission Electron Microscopy (HRTEM) showed that the alpha/beta interface phase in the alloy existed before electropolishing and it could decompose during prolonged aging. In this paper, these evidences will be presented. It was observed from a strained region of a tensile sample along the longitudinal direction that the dislocation slip bands exist across the alpha platelets. At a higher magnification, it was noted that the dislocations that pass through the alpha platelet boundary regions and also cut through the alpha/beta interface phase. From the HRTEM image of the ledge formed by the dislocations cutting through a platelet boundary, the glide plane of the dislocations is identified. it clearly showed chat the alpha/beta interface phase had existed before the tensile test was conducted. Moreover, it was also found that the decomposition of the alpha platelet occurred during the prolonged aging up to 3000 h at 550 degrees C and the resultant product, silicide, was formed on the platelet boundary after aging. Around the decomposed beta phase, the alpha/beta interface phase disappeared, but: still existed around the non-decomposed part of the boundary beta phase. The evidences imply that the alpha/beta interface phase also underwent decomposition or transformation while the beta phase was decomposed. Such evidence would not have existed if the alpha/beta interface phase is formed during electropolishing. The evidence also demonstrated that the alpha/beta interface phase not only is a real phase in the alloy employed in this case but also unstable and may change dramatically under thermal exposure, which should affect the mechanical properties of this alloy. (C) 2000 Elsevier Science S.A. All rights reserved.; There have been contradictory reports about the existence of an alpha/beta interface phase in titanium alloys over the last two decades. Recently some publications tend to Favour the notion that the interface phase is an artifact formed in the preparation of the thin foil by electropolishing. However our studies on an advanced near-alpha titanium alloy (Ti-5.5Al-3.98Sn-2.16Zr-0.95Mo-0.85Nd-0.28Si) especially by means of High Resolution Transmission Electron Microscopy (HRTEM) showed that the alpha/beta interface phase in the alloy existed before electropolishing and it could decompose during prolonged aging. In this paper, these evidences will be presented. It was observed from a strained region of a tensile sample along the longitudinal direction that the dislocation slip bands exist across the alpha platelets. At a higher magnification, it was noted that the dislocations that pass through the alpha platelet boundary regions and also cut through the alpha/beta interface phase. From the HRTEM image of the ledge formed by the dislocations cutting through a platelet boundary, the glide plane of the dislocations is identified. it clearly showed chat the alpha/beta interface phase had existed before the tensile test was conducted. Moreover, it was also found that the decomposition of the alpha platelet occurred during the prolonged aging up to 3000 h at 550 degrees C and the resultant product, silicide, was formed on the platelet boundary after aging. Around the decomposed beta phase, the alpha/beta interface phase disappeared, but: still existed around the non-decomposed part of the boundary beta phase. The evidences imply that the alpha/beta interface phase also underwent decomposition or transformation while the beta phase was decomposed. Such evidence would not have existed if the alpha/beta interface phase is formed during electropolishing. The evidence also demonstrated that the alpha/beta interface phase not only is a real phase in the alloy employed in this case but also unstable and may change dramatically under thermal exposure, which should affect the mechanical properties of this alloy. (C) 2000 Elsevier Science S.A. All rights reserved.
部门归属	univ london queen mary & westfield coll, dept mat, london e1 4ns, england. chinese acad sci, inst met res, atom imaging solids lab, shenyang 110015, peoples r china. chinese acad sci, inst met res, lab titanium alloys, shenyang 110015, peoples r china.;guo, zx (reprint author), univ london queen mary & westfield coll, dept mat, mile end rd, london e1 4ns, england ; univ london queen mary & westfield coll, dept mat, london e1 4ns, england. chinese acad sci, inst met res, atom imaging solids lab, shenyang 110015, peoples r china. chinese acad sci, inst met res, lab titanium alloys, shenyang 110015, peoples r china.;guo, zx (reprint author), univ london queen mary & westfield coll, dept mat, mile end rd, london e1 4ns, england
关键词	Alpha/beta Interface Alpha/beta Interface Titanium Alloy Titanium Alloy Hrtem Hrtem Electropolishing Electropolishing Platelet Platelet Boundary Boundary Resolution Resolution Ti Ti
URL	查看原文 ; 查看原文
WOS记录号	WOS:000085839800031 ; WOS:000085839800031
引用统计	被引频次：6[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/321006/37072
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	Q. Kang,Z. X. Guo,D. Li,et al. Evidence of the existence an alpha/beta interface phase in a near-alpha titanium alloy, Evidence of the existence an alpha/beta interface phase in a near-alpha titanium alloy[J]. Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing, Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing,2000, 2000,280, 280(1):182-186, 182-186.
APA	Q. Kang,Z. X. Guo,D. Li,&Y. Y. Liu.(2000).Evidence of the existence an alpha/beta interface phase in a near-alpha titanium alloy.Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing,280(1),182-186.
MLA	Q. Kang,et al."Evidence of the existence an alpha/beta interface phase in a near-alpha titanium alloy".Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing 280.1(2000):182-186.