Effect of combined addition of Ag and Cu on the precipitation behavior for an Al-Mg-Si alloy
Effect of combined addition of Ag and Cu on the precipitation behavior for an Al-Mg-Si alloy
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Ag和Cu联合添加对Al-Mg-Si合金析出行为的影响
DOI：
10.1016/j.matchar.2020.110736
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发表时间：
2021-01-28
影响因子：
4.7
通讯作者：
Liu, Qing
中科院分区：
文献类型：
--
作者：
Weng, Yaoyao;Ding, Lipeng;Liu, Qing
通过原子分辨率高角度环形暗场扫描透射电子显微镜（HAADF - STEM）和三维原子探针（3DAP）分析，系统地研究了Ag和Cu共同添加对Al - Mg - Si合金析出行为的影响。在时效初期，Ag和Cu原子参与团簇过程，并加速团簇向GP区和β″相的转变。在峰时效阶段，Ag原子优先偏聚在β″/α - Al界面，而Cu原子进入β″相内部并形成一种对称的亚结构，即Cu亚单元团簇。随着时效时间延长，Ag原子逐渐并入β″相并形成Ag亚单元团簇。在过时效阶段，并入的Ag和Cu原子可促进β′Ag、无序QP1和QP2相的形成。几乎所有这些析出相都具有包含各种晶胞（β′、β′(Ag)、Q′和C）或亚结构（LDC、Cu亚单元团簇、Ag亚单元团簇）的复合结构，并且在这些析出相的界面发现有Ag偏聚。对于板条状QP2相，Cu和Ag原子分别偏聚在共格和半共格的QP2/α - Al界面，这可降低它们的应变能和界面能。这些发现为理解Al - Mg - Si - Ag - Cu合金的析出相演变提供了新的见解，该合金是一种有潜力应用于汽车的合金。
The effect of combined addition of Ag and Cu on the precipitation behavior for an Al-Mg-Si alloy was systematically investigated by atomic resolution high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and three-dimensional atom probe (3DAP) analysis. At the early aging stage, Ag and Cu atoms participate in the clustering process and accelerate the transformation of clusters to GP zones and beta '' phases. In the peak aging stage, Ag atoms preferentially segregate at the beta ''/alpha-Al interfaces, while Cu atoms enter into the interior of the beta '' phase and form a symmetry substructure, Cu sub-unit clusters. With prolonged aging, Ag atoms gradually incorporate in the beta '' phase and form Ag sub-unit clusters. The incorporated Ag and Cu atoms can promote the formation of beta' Ag , disordered QP1 and QP2 phases during the over aging stage. Almost all of these precipitates have a composite structure with various unit cells (beta', beta'(Ag), Q' and C) or substructures (LDC, Cu sub-unit clusters, Ag sub-unit clusters), and Ag segregation is found in the interfaces of these precipitates. For the lath-like QP2 phase, Cu and Ag atoms segregate at the coherent and semi-coherent QP2/alpha-Al interfaces, respectively, which can reduce their strain energy and interfacial energy. These findings provide new insights in understanding the precipitate evolution of the Al-Mg-Si-Ag-Cu alloy, which is a potential alloy for automobile applications.