Characterisation of structural similarities of precipitates in Mg-Zn and Al-Zn-Mg alloys systems
Characterisation of structural similarities of precipitates in Mg-Zn and Al-Zn-Mg alloys systems
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DOI：
10.1080/14786435.2019.1637032
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发表时间：
2019-07-04
影响因子：
1.6
通讯作者：
Homma, Tomoyuki
中科院分区：
文献类型：
--
作者：
Bendo, Artenis;Maeda, Tomoyoshi;Homma, Tomoyuki
用高角度环形暗场扫描透射电子显微镜观察了Al-Zn-Mg和Mg-Zn合金中的析出相结构。Al-Zn-Mg中的析出组织通常是由镁锌笔花砖形成的，但也经常观察到以两种不同的方式结合了镁锌长六角结构。在镁-锌和铝-锌-镁合金中，镁锌块和镁锌块的镶嵌都产生了与单一单斜相的镁锌7或镁锌2单元的化学和结构配置不同的整体图案。发现析出物的形态与其内部的亚单位晶胞排列有关，尤其是与长六角形的镁锌相有关。结果表明，在析出物中，镁锌长六方相的系统排列或随机排列，以及由此产生的成分和结构模式，与析出物的长径比和析出物/基质界面的变化密切相关。
High angle annular dark field scanning transmission electron microscopy has been employed to observe precipitate structures in Al-Zn-Mg and Mg-Zn alloys. precipitate structures in Al-Zn-Mg are commonly formed by MgZn2 Penrose bricks, but also frequently observed to incorporate Mg6Zn7 elongated hexagons via two different modes. Tilings of MgZn2 and Mg6Zn7 building blocks in both in Mg-Zn and in Al-Zn-Mg alloys, create overall patterns which deviate from the chemical and structural configuration of solely monoclinic Mg4Zn7 or MgZn2 unit cells. Precipitate morphologies were found to be correlated to their internal sub-unit cell arrangements, especially to Mg6Zn7 elongated hexagons. Systematic or random arrangements of Mg6Zn7 elongated hexagons inside precipitates and therefore compositional and structural patterns, were found to be strongly related to the aspect ratio of the precipitates and altering of the precipitate/matrix interfaces.[GRAPHICS]