2020 Volume 45 Issue 5 Pages 167-172
To investigate the formation of a Mg-based long-period stacking ordered (LPSO) structure, we systematically studied the preference of the short-range order (SRO) in metastable disordered phases of Mg-RE-Zn (RE = Y, La, Er, Ho, Dy, Tb) and Mg-Gd-Al ternary alloy systems through first-principles calculations. Both the RE-Zn (RE = Y, Er, Ho, Dy, Tb) and Gd-Al pair cluster probabilities exhibited an increasing tendency. On the other hand, in a Mg-La-Zn system, which does not form an LPSO structure, the La-Zn pair cluster probability does not increase. This preference toward SRO in the disordered phases of Mg-based ternary alloys indicates that L12-type ordering in the LPSO structure as well as the possibility of LPSO formation should have a strong correlation with the SRO tendency of energetically competitive disordered phases.