Effect of alloying elements on the formation and structural features of long period stacking structures in as-cast Mg alloys

Mg97Y2M1(M=Zn, Ni, Ag) alloys were prepared by induction melting method. The characteristics of long period stacking structures (LPS) formed in these alloys were studied by TEM and SEM. The results show that the LPS in the as-cast Mg97Y2Zn1 can be described with a 6-layer stacking period, which is different from the typical 6H type with a hexagonal structure. The existence of LPS in the Mg-Y-Ni system has also been found, but its lattice distortion occurs more often than that in the Mg-Y-Zn system. In contrast, no LPS structure is observed in the Mg-Y-Ag sysyem. On the basis of experimental results, the factors affecting the formation of LPS structures in Mg97Y2M1 alloys are also discussed.