Aberration-corrected scanning transmission electron microscopy study of β′-like precipitates in an Al-Mg-Ge alloy

被引：19

作者：

Bjorge, R. ^{[1
]}

Dwyer, C. ^{[2
,3
,4
]}

Weyland, M. ^{[2
,3
]}

Nakashima, P. N. H. ^{[3
,4
]}

Marioara, C. D. ^{[5
]}

Andersen, S. J. ^{[5
]}

Etheridge, J. ^{[2
,3
]}

Holmestad, R. ^{[1
]}

机构：

[1] Norwegian Univ Sci & Technol, Dept Phys, N-7491 Trondheim, Norway

[2] Monash Univ, Monash Ctr Electron Microscopy, Clayton, Vic 3800, Australia

[3] Monash Univ, Dept Mat Engn, Clayton, Vic 3800, Australia

[4] Monash Univ, ARC Ctr Excellence Design Light Met, Clayton, Vic 3800, Australia

[5] SINTEF Mat & Chem, Dept Synth & Properties, N-7465 Trondheim, Norway

来源：

ACTA MATERIALIA | 2012年 / 60卷 / 6-7期

基金：

澳大利亚研究理事会;

关键词：

Aluminium alloys; Precipitation; High angle annular dark field; Scanning transmission electron microscopy; CRYSTAL-STRUCTURE; SI; PHASE;

D O I：

10.1016/j.actamat.2012.02.039

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Precipitates in an Al-Mg-Ge alloy similar to the beta' phase in Al-Mg-Si alloys were investigated using qualitative and quantitative aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF STEM). The needle-shaped beta'-Ge precipitates are coherent with the Al matrix along the needle direction which is parallel to a < 001 >(Al) direction, as well as one direction in the cross-section plane that is parallel to a < 100 >(Al) direction. This is linked to a smaller lattice parameter in the needle cross-section plane than that of coarser, less coherent beta' precipitates in Al-Mg-Si alloys, despite Ge having a larger atomic radius than Si. Quantitative HAADF STEM results show that the nominal Ge columns of the beta'-Ge precipitates are not fully occupied by Ge, the intensity of these columns being consistent with an Al concentration of 30 +/- 10%, or a vacancy concentration of 20 +/- 10%. The coherent interface is atomically smooth, but with matrix columns containing Ge spaced periodically along the interface. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

引用

页码：3239 / 3246

页数：8

共 29 条

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