Co-segregation of Mg and Zn atoms at the planar eta(1)-precipitate/Al matrix interface in an aged Al-Zn-Mg alloy

BQ Cheng and XJ Zhao and Y Zhang and HW Chen and I Polmear and JF Nie, SCRIPTA MATERIALIA, 185, 51-55 (2020).

DOI: 10.1016/j.scriptamat.2020.04.004

Using aberration-corrected scanning transmission electron microscopy, the interface between Thprecipitates and Al matrix in the aged Al-2.1Zn-1.7Mg (at.%) alloy has been investigated. Atomic-resolution X-ray dispersive spectroscopy mapping reveals the occurrence of co- segregation of Mg and Zn atoms in the 002(alpha) habit plane of the eta(1)(MgZn2) precipitates. Site-specific Mg atoms segregate outside the concave of an outermost zig-zag Zn-rich layer of the eta(1) habit plane. Zn segregation surround the segregated Mg atomic columns was also observed. Hybrid molecular dynamics (MD) and Monte Carlo (MC) atomistic simulations with the accuracy of density functional theory indicate the site-specific segregation is energetically favourable. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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