The phase compositions of a Mg-2Dy-0.5Zn (at.%) alloy under different solid solution temperature was investigated by differential thermal analysis (DSC), X-ray diffraction (XRD), optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results indicated that the as-cast sample was mainly composed of an 18R long period stacking ordered (LPSO) phase and Mg matrix. The disappearance of 18R-LPSO phase, together with the presence of 14H-LPSO phase, occurred when solid solution treatment (SST) was at 535 °C. When the temperature was higher than 535 °C, the 18R-LPSO phase was detected again companied with a new Mg8ZnDy eutectic phase.
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