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

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	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
刊名	Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing
	2000
卷号	280 期号:1 页码:182-186
关键词	alpha/beta interface titanium alloy HRTEM electropolishing platelet boundary resolution ti
ISSN号	0921-5093
中文摘要	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.
原文出处	://WOS:000085839800031
公开日期	2012-04-14
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/37072]
专题	金属研究所_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[J]. Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing,2000,280(1):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.