First-principles study of long-period stacking ordered-like multi-stacking fault structures in pure magnesium

Multi-stacking fault structures in pure magnesium similar to long-period stacking ordered phases of Mg–Y–Zn alloys have been investigated systematically from first-principles calculations. Based on stacking fault energy, the favorable multi-stacking fault structures are in general accordance with experimental observations. Furthermore, the present investigations indicate that inter-transformation occurs mainly between long-period stacking ordered structures with the same type of stacking faults when their lower stacking fault energies are closer. Calculated electronic structures reveal two different mechanisms for I1–I1 and I2–I2 interactions.

Research highlights
► LPSO-like MSFSs could be classified into two groups with only I1 or I2 faults.
► The favorable MSFSs obtained are in accordance with experimental observation.
► LPSO inter-transformation occurs when their MSFSs have same type SFs and closer SFEs.
► Electronic structures reveal two mechanisms for I1-I1 and I2-I2 SF interactions.