On the prismatic precipitate plates in Mg-Ca-In alloys

Prismatic precipitate plates in an age hardenable Mg-Ca-In alloy are characterized by atomic-resolution high-angle annular dark-field scanning transmission electron microscopy. The precipitate phase, designated delta, has a monoclinic structure. The proposed crystal structure of the delta is supported by first-principles calculations and multi-slice image simulations. The delta plates form with a considerably large dilatational strain in the direction perpendicular to their habit plane, and this strain is accommodated elastically. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.