Nano-precipitates made of atomic pillars revealed by single atom detection in a Mg-Nd alloy

Abstract : We report on the atomic architecture of metastable precipitates in a model Mg-0.5 at. %Nd system. High resolution Z-contrast observations in scanning transmission electron microscopy demonstrate that a common elementary structure, made of Nd atomic pillars, is shared by precipitates involved in the early decomposition of the system. A combination of Z-contrast projections has been used to establish the accurate location of Nd atoms in the atomic pillars, therefore allowing the determination of structure and composition of precipitates. Other precipitates compositions are extrapolated by means of a quantitative analysis. The ANR (Agence Nationale pour la Recherche) is thanked for the financial support through the Programme Jeune Chercheur–Jeune Chercheuse TIPSTEM. Jörn Fiedler from Clausthal University is gratefully acknowledged for the alloy preparation.