Atomic scale investigation of a novel metastable structure in aged Mg–Nd alloys

• DOI: 10.1016/j.scriptamat.2018.10.005
• Publication Date: 2018-10-11T01:49:54Z
• Authors: B.Z. Sun; J. Tan; H.X. Zhang; Y.H. Sun
• Keywords: Metastability; Orthorhombic crystal system; Basal plane; Atomic units; Lattice (music)

Abstract Aged Mg-3.0 wt% Nd alloys were investigated by high angle annular dark-field scanning transmission electron microscopy. A hitherto unreported metastable phase designated β 3 can always emerge at the endpoints of β 1 particles. The crystal structure of β 3 phase is determined to an orthorhombic lattice (space group Cmcm ). With the {111} β 1 planes acting as the basal plane of growth, β 3 phase has three types of variants, which are related by a 120° rotation with respect to each other around the same [001] β 3 axis. In addition, several peculiar morphologies and further evolution of β 3 phase were also analyzed.