A new metastable phase in dilute, hot-rolled Mg–Nd alloys

Highlights: ► A yet non-documented intermetallic phase is observed in hot-rolled Mg–Nd alloys. ► The second-phase particles are strongly faceted with cuboidal morphology. ► The phase has an ordered cubic crystal structure with point group, m3m. ► Energy dispersive spectroscopy analysis indicates a stoichiometry of Mg3Nd. ► The lattice parameter, a ≈ 10.9 Å, differs from the well-known cubic Mg3Nd phase. - Abstract: The addition of rare earth (RE) elements to Mg alloys can result in weaker hot deformation and recrystallization textures than those present in conventional Mg alloys. Recent studies of hot-rolled Mg–Nd binary alloys suggest that the texture weakening is influenced by the presence of second-phase particles. In this follow-up study, these particles are characterized morphologically, chemically, and crystallographically using transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The particles were observed to have a faceted morphology, particularly in the richer concentrations investigated, a composition of approximately 25 at.% Nd (a stoichiometry of Mg3Nd) and an ordered cubic crystal structure (m3m point group) with a lattice parameter of approximately a ≈ 10.9 Å, which is distinct from that of the equilibrium Mg3Nd phase.