Synergistic impact of Mg and Ge co-doping on stacking fault energy and underlying mechanisms in Al

• Published in: Physica scripta 2025-01, Vol.100 (1), p.15997
• Main Authors: Yu, Libin, Li, Yawen, Pang, Xueyong, Qin, Gaowu
• Format: Article
• Language: English
• Subjects: aluminum alloy; co-doping; electronic structure; first-principles calculation; stacking fault energy
• ISSN: 0031-8949; 1402-4896
• DOI: 10.1088/1402-4896/ad9fb7

This study utilizes first-principles calculations to explore the impact of element additions of Mg and Ge on the stacking fault energy (SFE) of aluminum alloys, with a particular emphasis on elucidating the electronic structure modifications underlying these effects. The findings indicate that both Mg and Ge additions, either alone or in combination, substantially diminish the SFE of the Al alloys, with Ge additions exhibiting a more marked influence. The introduction of Mg and Ge elements alters the electronic structure of the Al-based alloy, largely due to adjustments in the interplanar spacing. Specifically, Ge additions lead to a more uniform electron cloud distribution, while Mg additions cause a redistribution of charge density. Building upon the computed SFE results, this study further analyzes their implications on plastic deformation. The mechanisms behind the SFE reduction differ: Al alloys with Mg additions achieve this through increased interlayer spacing and weakened bonding strength, whereas those with Ge additions exhibit a combination of larger interlayer spacing and a homogeneous region of low Electron Localization Function. By linking electronic structure analysis with the SFE and its effects on plastic deformation, this study offers profound insights into the underlying reasons for the observed changes in SFE. Ultimately, it provides a theoretical foundation for designing novel Al alloys with tailored mechanical properties through precise control of element additions of Mg and Ge.