LAUSR

Abstract After solid solution and aging treatment, Mg–3.0 wt%Y–1.0 wt%Ce ternary alloys were characterized using high angle annular dark field scanning transmission electron microscopy. The main precipitates are dominated by β′ phase and Mg17Ce2, a Ni17Th2–type intermetallic compound. An orientation domain can be discerned generally in Mg17Ce2 granules. This domain structure of Mg17Ce2 always consists of two types of domains (defined as domain–Ι and domain–Π) with a 90 degree orientation difference. In terms of crystallographic orientation relationships among α-Mg matrix and both domains, the domain–Ι is parallel to α-Mg matrix, whereas, the domain–Π is perpendicular to α-Mg matrix. It can be certain that a 1 ¯ 010 direction is an unchanged orientation. Due to nearly equal values of lattice parameters (a and c) of Mg17Ce2, both domain–Ι and domain–Π can matches well with α-Mg matrix. Comparatively, the interfacial matching between domain–Ι and α-Mg matrix is better, suggesting that the domain–Ι is dominant.