Atomic structure and growth mechanism of T1 precipitate in Al-Cu-Li-Mg-Ag alloy

The atomic structure of a 0.94-nm-thick T-1 precipitate in an Al-Cu-Li-Mg-Ag alloy is investigated by combining aberration-corrected scanning transmission electron microscopy (STEM) and energy-dispersive X-ray spectroscopy (EDX). Ag segregates at the first layer of the T-1 precipitate interface, revealing a significant compositional variation of Ag throughout the interface. Moreover, the T-1 precipitate thickened from 0.94 nm with successive stacking of identical 0.94 nm thick layers. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.