Phase formation and structures of quasicrystals and approximants in the Zn-Mg-(Ti, Zr, Hf) system

S. Ohhashi; E. Abe; M. Tanaka; A. P. Tsai

doi:10.1016/j.actamat.2009.06.027

Phase formation and structures of quasicrystals and approximants in the Zn-Mg-(Ti, Zr, Hf) system

S. Ohhashi, E. Abe, M. Tanaka, A. P. Tsai

Research output: Contribution to journal › Article › peer-review

12 Citations (Scopus)

Abstract

The compositional regions for primitive (P) and face-centered (F) icosahedral quasicrystals (iQc) have been determined to be around Zn₈₄Mg₉Zr₇ and Zn₇₅Mg₁₈Zr₆, respectively. A 1/1 approximant of the F-type iQc was found to have a composition around Zn₇₇Mg₁₈Zr₅. A similar tendency has been verified for the Zn-Mg-Hf system. No stable iQc was observed in the Zn-Mg-Ti system. High-resolution X-ray measurements performed with synchrotron radiation showed that the stable iQcs are highly ordered and contain less phason disorder. High-angle annular dark field (HAADF) scanning transmission electron microscopy observation of the 1/1 Zn-Mg-Hf approximant effectively revealed the Hf positions in the structure, whose local contrasts can be reasonably interpreted by a structural model where icosahedral and dodecahedral Hf clusters are mutually interpenetrated. Similar appearances of local contrasts were frequently observed in HAADF images of the F-type iQc, indicating that the iQc structure is also build up of icosahedral clusters that are almost identical to those in the 1/1 approximant.

Original language	English
Pages (from-to)	4727-4735
Number of pages	9
Journal	Acta Materialia
Volume	57
Issue number	16
DOIs	https://doi.org/10.1016/j.actamat.2009.06.027
Publication status	Published - 2009 Sept
Externally published	Yes

Keywords

Bergman cluster
Quasicrystal
Structure
Zinc-magnesium-zirconium

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Ceramics and Composites
Polymers and Plastics
Metals and Alloys

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10.1016/j.actamat.2009.06.027

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@article{443a0bc4ec6547b282fc4f54c8f40a4f,

title = "Phase formation and structures of quasicrystals and approximants in the Zn-Mg-(Ti, Zr, Hf) system",

abstract = "The compositional regions for primitive (P) and face-centered (F) icosahedral quasicrystals (iQc) have been determined to be around Zn84Mg9Zr7 and Zn75Mg18Zr6, respectively. A 1/1 approximant of the F-type iQc was found to have a composition around Zn77Mg18Zr5. A similar tendency has been verified for the Zn-Mg-Hf system. No stable iQc was observed in the Zn-Mg-Ti system. High-resolution X-ray measurements performed with synchrotron radiation showed that the stable iQcs are highly ordered and contain less phason disorder. High-angle annular dark field (HAADF) scanning transmission electron microscopy observation of the 1/1 Zn-Mg-Hf approximant effectively revealed the Hf positions in the structure, whose local contrasts can be reasonably interpreted by a structural model where icosahedral and dodecahedral Hf clusters are mutually interpenetrated. Similar appearances of local contrasts were frequently observed in HAADF images of the F-type iQc, indicating that the iQc structure is also build up of icosahedral clusters that are almost identical to those in the 1/1 approximant.",

keywords = "Bergman cluster, Quasicrystal, Structure, Zinc-magnesium-zirconium",

author = "S. Ohhashi and E. Abe and M. Tanaka and Tsai, {A. P.}",

note = "Funding Information: We appreciate Dr. C.P Gomez for stimulating discussion on the cluster structure of Zn–Mg–Hf 1/1 approximant and for critical reading of manuscript. We thank Dr. Takakura for discussion of the structure of iQc in the Zn–Mg–Hf (Ho) system. Valuable discussion with Dr. N. Fujita is also highly appreciated. E.A acknowledges a support by a Grant-in-Aid for Scientific Research of Priority Areas {\textquoteleft}Atomic Scale Modification{\textquoteright} from the Ministry of Education, Science, Sports and Culture of Japan.",

year = "2009",

month = sep,

doi = "10.1016/j.actamat.2009.06.027",

language = "English",

volume = "57",

pages = "4727--4735",

journal = "Acta Materialia",

issn = "1359-6454",

publisher = "Elsevier Limited",

number = "16",

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TY - JOUR

T1 - Phase formation and structures of quasicrystals and approximants in the Zn-Mg-(Ti, Zr, Hf) system

AU - Ohhashi, S.

AU - Abe, E.

AU - Tanaka, M.

AU - Tsai, A. P.

N1 - Funding Information: We appreciate Dr. C.P Gomez for stimulating discussion on the cluster structure of Zn–Mg–Hf 1/1 approximant and for critical reading of manuscript. We thank Dr. Takakura for discussion of the structure of iQc in the Zn–Mg–Hf (Ho) system. Valuable discussion with Dr. N. Fujita is also highly appreciated. E.A acknowledges a support by a Grant-in-Aid for Scientific Research of Priority Areas ‘Atomic Scale Modification’ from the Ministry of Education, Science, Sports and Culture of Japan.

PY - 2009/9

Y1 - 2009/9

N2 - The compositional regions for primitive (P) and face-centered (F) icosahedral quasicrystals (iQc) have been determined to be around Zn84Mg9Zr7 and Zn75Mg18Zr6, respectively. A 1/1 approximant of the F-type iQc was found to have a composition around Zn77Mg18Zr5. A similar tendency has been verified for the Zn-Mg-Hf system. No stable iQc was observed in the Zn-Mg-Ti system. High-resolution X-ray measurements performed with synchrotron radiation showed that the stable iQcs are highly ordered and contain less phason disorder. High-angle annular dark field (HAADF) scanning transmission electron microscopy observation of the 1/1 Zn-Mg-Hf approximant effectively revealed the Hf positions in the structure, whose local contrasts can be reasonably interpreted by a structural model where icosahedral and dodecahedral Hf clusters are mutually interpenetrated. Similar appearances of local contrasts were frequently observed in HAADF images of the F-type iQc, indicating that the iQc structure is also build up of icosahedral clusters that are almost identical to those in the 1/1 approximant.

AB - The compositional regions for primitive (P) and face-centered (F) icosahedral quasicrystals (iQc) have been determined to be around Zn84Mg9Zr7 and Zn75Mg18Zr6, respectively. A 1/1 approximant of the F-type iQc was found to have a composition around Zn77Mg18Zr5. A similar tendency has been verified for the Zn-Mg-Hf system. No stable iQc was observed in the Zn-Mg-Ti system. High-resolution X-ray measurements performed with synchrotron radiation showed that the stable iQcs are highly ordered and contain less phason disorder. High-angle annular dark field (HAADF) scanning transmission electron microscopy observation of the 1/1 Zn-Mg-Hf approximant effectively revealed the Hf positions in the structure, whose local contrasts can be reasonably interpreted by a structural model where icosahedral and dodecahedral Hf clusters are mutually interpenetrated. Similar appearances of local contrasts were frequently observed in HAADF images of the F-type iQc, indicating that the iQc structure is also build up of icosahedral clusters that are almost identical to those in the 1/1 approximant.

KW - Bergman cluster

KW - Quasicrystal

KW - Structure

KW - Zinc-magnesium-zirconium

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DO - 10.1016/j.actamat.2009.06.027

M3 - Article

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SN - 1359-6454

VL - 57

SP - 4727

EP - 4735

JO - Acta Materialia

JF - Acta Materialia

IS - 16

ER -

Phase formation and structures of quasicrystals and approximants in the Zn-Mg-(Ti, Zr, Hf) system

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Keywords

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