Microstructure investigation of the 6H-type long-period stacking order phase in Mg97Y2Zn1 alloy

The microstructures of the 6H-type long-period stacking order in Mg97Y2Zn1 alloy were investigated by first-principles calculations. The arrangement rule and accurate positions of Zn and Y atoms were determined theoretically for the first time. The variations of unit cell geometry and lattice constants were investigated in detail. At particular, calculations revealed that the element substitution of 2% Zn or more in the phase is the origin of the lattice distortion in this novel structure. The results were in good accordance with experimental observations.