Aperiodic structures of rod-shaped precipitates in a Mg-Zn-Al alloy

Yunhe Zheng; Laure Bourgeois; Jian Feng Nie

doi:10.1016/j.scriptamat.2021.114189

Aperiodic structures of rod-shaped precipitates in a Mg-Zn-Al alloy

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

Abstract

Rod-shaped precipitates with their long axis parallel to [0001]_α commonly form in Mg-Zn-Al alloys, providing strengthening effects. These precipitates are metastable and are generally accepted to be the MgZn₂ and/or Mg₄Zn₇ phases. In this paper, the cross-sectional structure of precipitate rods in an aged ZA84 alloy is examined at the atomic scale using high-angle annular dark-field scanning transmission electron microscopy. It is found that these precipitates are neither pure MgZn₂ nor Mg₄Zn₇. The structures of the rod-shaped precipitates do not have long-range translational symmetry nor long-range 5-fold rotational symmetry in the two-dimensional projection plane perpendicular to the rod long axis. However, these structures can be described by the tiling of different shapes, with four such shapes being most frequently observed. The structural details revealed in this work may help rationalize the many complex precipitate structures in Mg-Zn-Al and Mg-Zn alloys.

Original language	English
Article number	114189
Number of pages	5
Journal	Scripta Materialia
Volume	205
DOIs	https://doi.org/10.1016/j.scriptamat.2021.114189
Publication status	Published - Dec 2021

Keywords

Magnesium alloys
Precipitation
Quasicrystal
Scanning transmission electron microscopy

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10.1016/j.scriptamat.2021.114189

349239229-oaAccepted author manuscript, 182 KBLicence: CC BY-NC-ND

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title = "Aperiodic structures of rod-shaped precipitates in a Mg-Zn-Al alloy",

abstract = "Rod-shaped precipitates with their long axis parallel to [0001]α commonly form in Mg-Zn-Al alloys, providing strengthening effects. These precipitates are metastable and are generally accepted to be the MgZn2 and/or Mg4Zn7 phases. In this paper, the cross-sectional structure of precipitate rods in an aged ZA84 alloy is examined at the atomic scale using high-angle annular dark-field scanning transmission electron microscopy. It is found that these precipitates are neither pure MgZn2 nor Mg4Zn7. The structures of the rod-shaped precipitates do not have long-range translational symmetry nor long-range 5-fold rotational symmetry in the two-dimensional projection plane perpendicular to the rod long axis. However, these structures can be described by the tiling of different shapes, with four such shapes being most frequently observed. The structural details revealed in this work may help rationalize the many complex precipitate structures in Mg-Zn-Al and Mg-Zn alloys.",

keywords = "Magnesium alloys, Precipitation, Quasicrystal, Scanning transmission electron microscopy",

author = "Yunhe Zheng and Laure Bourgeois and Nie, \{Jian Feng\}",

note = "Funding Information: The authors acknowledge the financial support from the Australian Research Council and the use of the instruments and scientific and technical assistance at the Monash Centre for Electron Microscopy, a Node of Microscopy Australia. This research used equipment funded by the Australian Research Council grants LE0454166 and LE110100223 . Publisher Copyright: {\textcopyright} 2021 Copyright: Copyright 2021 Elsevier B.V., All rights reserved.",

year = "2021",

month = dec,

doi = "10.1016/j.scriptamat.2021.114189",

language = "English",

volume = "205",

journal = "Scripta Materialia",

issn = "1359-6462",

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TY - JOUR

T1 - Aperiodic structures of rod-shaped precipitates in a Mg-Zn-Al alloy

AU - Zheng, Yunhe

AU - Bourgeois, Laure

AU - Nie, Jian Feng

N1 - Funding Information: The authors acknowledge the financial support from the Australian Research Council and the use of the instruments and scientific and technical assistance at the Monash Centre for Electron Microscopy, a Node of Microscopy Australia. This research used equipment funded by the Australian Research Council grants LE0454166 and LE110100223 . Publisher Copyright: © 2021 Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2021/12

Y1 - 2021/12

N2 - Rod-shaped precipitates with their long axis parallel to [0001]α commonly form in Mg-Zn-Al alloys, providing strengthening effects. These precipitates are metastable and are generally accepted to be the MgZn2 and/or Mg4Zn7 phases. In this paper, the cross-sectional structure of precipitate rods in an aged ZA84 alloy is examined at the atomic scale using high-angle annular dark-field scanning transmission electron microscopy. It is found that these precipitates are neither pure MgZn2 nor Mg4Zn7. The structures of the rod-shaped precipitates do not have long-range translational symmetry nor long-range 5-fold rotational symmetry in the two-dimensional projection plane perpendicular to the rod long axis. However, these structures can be described by the tiling of different shapes, with four such shapes being most frequently observed. The structural details revealed in this work may help rationalize the many complex precipitate structures in Mg-Zn-Al and Mg-Zn alloys.

AB - Rod-shaped precipitates with their long axis parallel to [0001]α commonly form in Mg-Zn-Al alloys, providing strengthening effects. These precipitates are metastable and are generally accepted to be the MgZn2 and/or Mg4Zn7 phases. In this paper, the cross-sectional structure of precipitate rods in an aged ZA84 alloy is examined at the atomic scale using high-angle annular dark-field scanning transmission electron microscopy. It is found that these precipitates are neither pure MgZn2 nor Mg4Zn7. The structures of the rod-shaped precipitates do not have long-range translational symmetry nor long-range 5-fold rotational symmetry in the two-dimensional projection plane perpendicular to the rod long axis. However, these structures can be described by the tiling of different shapes, with four such shapes being most frequently observed. The structural details revealed in this work may help rationalize the many complex precipitate structures in Mg-Zn-Al and Mg-Zn alloys.

KW - Magnesium alloys

KW - Precipitation

KW - Quasicrystal

KW - Scanning transmission electron microscopy

UR - https://www.scopus.com/pages/publications/85112333895

U2 - 10.1016/j.scriptamat.2021.114189

DO - 10.1016/j.scriptamat.2021.114189

M3 - Article

AN - SCOPUS:85112333895

SN - 1359-6462

VL - 205

JO - Scripta Materialia

JF - Scripta Materialia

M1 - 114189

ER -

Aperiodic structures of rod-shaped precipitates in a Mg-Zn-Al alloy

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Keywords

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Advanced in-situ electron microscope facility for research in alloys, nanomaterials, functional materials, magnetic materials and minerals

Monash Centre for Electron Microscopy (MCEM)

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Aperiodic structures of rod-shaped precipitates in a Mg-Zn-Al alloy

Abstract

Keywords

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Advanced in-situ electron microscope facility for research in alloys, nanomaterials, functional materials, magnetic materials and minerals

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Monash Centre for Electron Microscopy (MCEM)

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