Local strain fields of LPSO in Mg-based ternary alloys

L1₂-type TM₆RE₈ clusters are distributed in enriched layers of LPSO (long period stacking ordered structure), and shrink in the [0001]_Mg direction. The growth mechanism of LPSOs was investigated from the viewpoint of a local strain field. The strength of out-of plane normal strain of the enriched layer varied with the average radius of solute elements in the layer. The first principle calculation showed that there is a relationship between the average atomic radius of solute elements and the structural relaxation in the clusters. Zn conclusion, it is suggested that the difference of average atomic radius between Mg and solute elements controls the degree of the cluster shrinkage by the displacement of the solute elements, and that it is the dominant factor giving rise to the out-of plane normal strains of the enrichment layers.