Formation of lamellar phase with 18R-type LPSO structure in an as-cast Mg96Gd3Zn1(at%) alloy

A lamellar Mg10GdZn phase was observed near the secondary eutectic β-phase ((Mg,Zn)3Gd) in an as-cast Mg-Gd-Zn alloy. It shows that the Mg10GdZn phase exhibits a 18R-type long period stacking ordered (LPSO) structure, while the lamellae within the α-Mg matrix exhibits a 14H-type LPSO structure. Moreover, it reveals that the hardness and elastic modulus of Mg10GdZn phase are much higher than those of the α-Mg by nano-mechanical measurements.