OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 2 2024 Results and discussion Figure 1 presents optical and TEM images of bimodal microstructure of the extruded Mg-2.9Nd-1.3Y alloy, which can be clearly observed in Fig. 1, a. TEM observations show that the microstructure of the extruded Mg-Nd-Y alloy is based on the hexagonal close packed (HCP) α-Mg phase solid solution (see Fig. 1, b) and intermetallic compounds based on Mg, Nd, Y. Intermetallic compounds can be observed inside grains and along grain boundaries (Fig. 1, b, c, d, e, f, g). According to [25–30], in Mg-Y-Nd system alloys these phases are identified as body centered cubic Mg24Y5 particles and three types of metastable phases. These phases include a face centered cubic (FCC) eutectic equilibrium β-phase (Mg14Nd2Y) in the form of a network, an orthorhombic b′-phase (Mg12YNd) with a globular morphology, and a FCC b1-phase (Mg3NdY) lamellas. Note that metastable β or β1 phases are considered to be the main reinforcing agents, which are usually present in the annealed WE43 alloy [25–29]. According to [28], in the deformed magnesium alloy WE43 during a long-term aging the metastable β1-phase is transformed into the equilibrium β-phase. a b c d e f g Fig. 1. Optical (а) and bright field TEM images (b, c, d, f, g), energy dispersive spectrums and elemental composition (d, e) of extruded Mg-2.9Y-1.3Nd alloy. Insert: selected area diffraction pattern
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