The building block of long-period structures in Mg-RE-Zn alloys

The long-period 14H structure that is frequently observed in Mg-RE-Zn (RE = rare-earth elements) alloys is characterized using atomic-resolution high-angle annular dark-field scanning transmission electron microscopy. It is demonstrated that the 14H structure consists of structural units that have an ABCA stacking sequence. The relationship between this structural unit and other long-period structures such as 18R is also discussed. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.