Studying GPI zones in Al-Zn-Mg alloys by 4D-STEM
Thronsen, Elisabeth; Frafjord, Jonas; Friis, Jesper; Marioara, Calin Daniel; Wenner, Sigurd; Andersen, Sigmund Jarle; Holmestad, Randi
Journal article, Peer reviewed
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Date
2021Metadata
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Original version
10.1016/j.matchar.2021.111675Abstract
A new methodology has been developed to study the fine details of GP zones in age-hardenable aluminium alloys. It is complementary to atomic resolution high-angle annular dark-field scanning transmission electron microscopy imaging, and combines scanning precession electron diffraction with diffraction simulations. To evaluate the method, data was collected from an Al-Zn-Mg alloy in a condition with a dense distribution of GPI zones. Diffraction patterns were recorded in the 〈001Al orientation, capturing GPI zones in three projections: along the unique [001]GPI axis, and along the two other mutually orthogonal orientations. The GPI zones viewed along [001]GPI revealed how the truncated octahedron units of the GPI zones were connected in multi-unit GP zones, while the two orientations normal to [001]GPI highlight the internal structure. The stability of the atomic models developed based on the experimental results was verified by density functional theory calculations.