Al-Cu approximants and associated B2 chemical-twinning modes

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	Al-Cu approximants and associated B2 chemical-twinning modes
	C. Dong; Q. H. Zhang; D. H. Wang; Y. M. Wang
	2000
发表期刊	Micron
ISSN	0968-4328
卷号	31 期号:5 页码:507-514
摘要	The Al3Cu4 alloy, with an ela ratio of 1.86 being close to ternary AI-Cu-TM (transition metal) quasicrystals, has been chosen for the search of AI-Cu approximants. Phase structures and compositions were studied using TEM, X-ray diffraction and EPMA techniques. Two new phases were found: face-centered orthorhombic oF-Al43.2Cu56.8 (a = 0.816(6), b = 1.414(9), c = 0.999(5) nm) and body-centered orthorhombic oI-Al41.3Cu58.7 (oI, a = 0.408(3), b = 0.707(4), c = 0.9995 nm). Their ela ratios are the same as that of the Al-Cu-Fe icosahedral quasicrystal. Both are B2 superstructures and their unit cell components can be expressed approximately as oF-Al(36)Cu(48)n square(12) and oI-Al(8)Cu(12)square(4) (square: vacancies). They both exist in twinning variants of the types 120 degrees/[001] and 180 degrees/[310]. Such twinning modes indicate that these orthorhombic phases are the decomposition products of a high-temperature parent phase epsilon 2-Al2Cu3, the atomic structure of which shows pentagonal atomic arrangements. Further analysis on the twinning modes of of and oI leads to the recognition of the chemical-twinning mode of the basic B2 structure as 180 degrees/[111](B2) This kind of chemical twinning mode is responsible for the pentagonal atomic configuration in the AI-Cu approximants as well as for the pseudo-5-fold B2 twinning. (C) 2000 Elsevier Science Ltd. All rights reserved.
部门归属	dalian univ technol, state key lab mat modificat laser ion & electron, dalian 116024, peoples r china. dalian univ technol, dept mat engn, dalian 116024, peoples r china. acad sinica, inst met res, shenyang 110015, peoples r china.;dong, c (reprint author), dalian univ technol, state key lab mat modificat laser ion & electron, dalian 116024, peoples r china
关键词	Al-cu System Quasicrystals Approximants Chemical Twinning Electron Microscopy Quasi-crystals System
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WOS记录号	WOS:000087050100008
引用统计	被引频次：18[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/321006/37019
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	C. Dong,Q. H. Zhang,D. H. Wang,et al. Al-Cu approximants and associated B2 chemical-twinning modes[J]. Micron,2000,31(5):507-514.
APA	C. Dong,Q. H. Zhang,D. H. Wang,&Y. M. Wang.(2000).Al-Cu approximants and associated B2 chemical-twinning modes.Micron,31(5),507-514.
MLA	C. Dong,et al."Al-Cu approximants and associated B2 chemical-twinning modes".Micron 31.5(2000):507-514.