Compositional evolution of long-period stacking ordered structures in magnesium studied by atom probe tomography

Mg alloys containing long-period stacking ordered (LPSO) structures are strong and ductile compared to conventional Mg alloys. We study here the compositional evolution of LPSO structures in a Mg97Y2Zn1 (at.%) alloy upon annealing at 500 degrees C using atom probe tomography. In the material annealed for 2.511, the Zn/Y ratio of the building blocks in the interdendritic LPSO phase (0.73) is close to the stoichiometric composition of Y(8)Zn(6)L1(2) clusters while that in plate-type LPSO structures (0.66) slightly deviates from the ideal value. The Y/Zn enrichment in LPSO structures in the alpha-Mg matrix slightly decreases with increasing annealing time. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.