HAADF-STEM study of chemical ordering in Al-Pd-Sc 1/1-crystal approximant

Yeong Gi So, Masahiro Nagao, Takuro Nagai, Koji Kimoto

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

The atomic structure of the Al 54Pd 31Sc 15 1/1-crystal approximant to the icosahedral quasicrystal has been studied using high-angle annular dark-field (HAADF) imaging in a scanning transmission electron microscopy (STEM). HAADF imaging directly reveals that the 1/1-phase has a periodic arrangement of Tsai-type atomic clusters, which consist of three successive shells with icosahedral symmetry as well as a disordered tetrahedron at the cluster center. In the 1/1-phase, the chemical ordering of Al and Pd is observed in the glue sites between the clusters, similar to that of Al and Au in the recently discovered Al 35Au 51Yb 14 1/1-phase, indicating a common structural feature of ternary Tsai-type approximants. Moreover, the preferential introduction of structural disorder into the second dodecahedral shell is observed in the HAADF images, which causes symmetry breaking of the 1/1-phase. On the basis of a comparison with the experimental and simulated images, a preliminary model for the atomic structure of the 1/1-phase is presented.

Original languageEnglish
Pages (from-to)7-11
Number of pages5
JournalJournal of Alloys and Compounds
Volume543
DOIs
Publication statusPublished - 2012 Dec 5
Externally publishedYes

Fingerprint

Transmission electron microscopy
Crystal atomic structure
Imaging techniques
Quasicrystals
Crystals
Scanning electron microscopy
Glues

Keywords

  • Al-Pd-Sc alloy
  • Annular dark-field imaging
  • Crystal approximant
  • Icosahedral quasicrystal
  • Scanning transmission electron microscopy

ASJC Scopus subject areas

  • Mechanical Engineering
  • Mechanics of Materials
  • Materials Chemistry
  • Metals and Alloys

Cite this

HAADF-STEM study of chemical ordering in Al-Pd-Sc 1/1-crystal approximant. / So, Yeong Gi; Nagao, Masahiro; Nagai, Takuro; Kimoto, Koji.

In: Journal of Alloys and Compounds, Vol. 543, 05.12.2012, p. 7-11.

Research output: Contribution to journalArticle

So, Yeong Gi ; Nagao, Masahiro ; Nagai, Takuro ; Kimoto, Koji. / HAADF-STEM study of chemical ordering in Al-Pd-Sc 1/1-crystal approximant. In: Journal of Alloys and Compounds. 2012 ; Vol. 543. pp. 7-11.
@article{38cae5fd378d42bbbbe34ba46f1768f0,
title = "HAADF-STEM study of chemical ordering in Al-Pd-Sc 1/1-crystal approximant",
abstract = "The atomic structure of the Al 54Pd 31Sc 15 1/1-crystal approximant to the icosahedral quasicrystal has been studied using high-angle annular dark-field (HAADF) imaging in a scanning transmission electron microscopy (STEM). HAADF imaging directly reveals that the 1/1-phase has a periodic arrangement of Tsai-type atomic clusters, which consist of three successive shells with icosahedral symmetry as well as a disordered tetrahedron at the cluster center. In the 1/1-phase, the chemical ordering of Al and Pd is observed in the glue sites between the clusters, similar to that of Al and Au in the recently discovered Al 35Au 51Yb 14 1/1-phase, indicating a common structural feature of ternary Tsai-type approximants. Moreover, the preferential introduction of structural disorder into the second dodecahedral shell is observed in the HAADF images, which causes symmetry breaking of the 1/1-phase. On the basis of a comparison with the experimental and simulated images, a preliminary model for the atomic structure of the 1/1-phase is presented.",
keywords = "Al-Pd-Sc alloy, Annular dark-field imaging, Crystal approximant, Icosahedral quasicrystal, Scanning transmission electron microscopy",
author = "So, {Yeong Gi} and Masahiro Nagao and Takuro Nagai and Koji Kimoto",
year = "2012",
month = "12",
day = "5",
doi = "10.1016/j.jallcom.2012.07.119",
language = "English",
volume = "543",
pages = "7--11",
journal = "Journal of Alloys and Compounds",
issn = "0925-8388",
publisher = "Elsevier BV",

}

TY - JOUR

T1 - HAADF-STEM study of chemical ordering in Al-Pd-Sc 1/1-crystal approximant

AU - So, Yeong Gi

AU - Nagao, Masahiro

AU - Nagai, Takuro

AU - Kimoto, Koji

PY - 2012/12/5

Y1 - 2012/12/5

N2 - The atomic structure of the Al 54Pd 31Sc 15 1/1-crystal approximant to the icosahedral quasicrystal has been studied using high-angle annular dark-field (HAADF) imaging in a scanning transmission electron microscopy (STEM). HAADF imaging directly reveals that the 1/1-phase has a periodic arrangement of Tsai-type atomic clusters, which consist of three successive shells with icosahedral symmetry as well as a disordered tetrahedron at the cluster center. In the 1/1-phase, the chemical ordering of Al and Pd is observed in the glue sites between the clusters, similar to that of Al and Au in the recently discovered Al 35Au 51Yb 14 1/1-phase, indicating a common structural feature of ternary Tsai-type approximants. Moreover, the preferential introduction of structural disorder into the second dodecahedral shell is observed in the HAADF images, which causes symmetry breaking of the 1/1-phase. On the basis of a comparison with the experimental and simulated images, a preliminary model for the atomic structure of the 1/1-phase is presented.

AB - The atomic structure of the Al 54Pd 31Sc 15 1/1-crystal approximant to the icosahedral quasicrystal has been studied using high-angle annular dark-field (HAADF) imaging in a scanning transmission electron microscopy (STEM). HAADF imaging directly reveals that the 1/1-phase has a periodic arrangement of Tsai-type atomic clusters, which consist of three successive shells with icosahedral symmetry as well as a disordered tetrahedron at the cluster center. In the 1/1-phase, the chemical ordering of Al and Pd is observed in the glue sites between the clusters, similar to that of Al and Au in the recently discovered Al 35Au 51Yb 14 1/1-phase, indicating a common structural feature of ternary Tsai-type approximants. Moreover, the preferential introduction of structural disorder into the second dodecahedral shell is observed in the HAADF images, which causes symmetry breaking of the 1/1-phase. On the basis of a comparison with the experimental and simulated images, a preliminary model for the atomic structure of the 1/1-phase is presented.

KW - Al-Pd-Sc alloy

KW - Annular dark-field imaging

KW - Crystal approximant

KW - Icosahedral quasicrystal

KW - Scanning transmission electron microscopy

UR - http://www.scopus.com/inward/record.url?scp=84865826571&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84865826571&partnerID=8YFLogxK

U2 - 10.1016/j.jallcom.2012.07.119

DO - 10.1016/j.jallcom.2012.07.119

M3 - Article

VL - 543

SP - 7

EP - 11

JO - Journal of Alloys and Compounds

JF - Journal of Alloys and Compounds

SN - 0925-8388

ER -