Formation of a lamellar 14H-type long period stacking ordered structure in an as-cast Mg–Gd–Zn–Zr alloy
2009
Wu, Y. J. | Lin, D. L. | Zeng, X. Q. | Peng, L.-M. | Ding, W. J.
A novel as-cast Mg₉₆.₈₂Gd₂Zn₁Zr₀.₁₈ alloy was produced by conventional ingot metallurgy. By scanning electron microscope and transmission electron microscope observations, its as-cast microstructure is mainly composed of the α′-Mg solid solution, the coherent fine-lamellae and the eutectic. The β-phase ((Mg,Zn)₃Gd) as the second phase in eutectic has a face-center cubic structure. While, the coherent lamellae consist of the 2H–Mg and the 14H-type long period stacking ordered (LPSO) structure. At present, the lamellar 14H-type LPSO structure has first been observed within α′-Mg matrix in the as-cast Mg–Gd–Zn–Zr alloys. It can be concluded that the lamellar 14H-type LPSO structure within α′-Mg matrix is a special structure obviously different from α-Mg matrix (2H-type structure) in structure, composition, and formation condition.
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