title: Two-dimensional ordering of solute nanoclusters at a close-packed stacking fault: modeling and experimental analysis.
abstract: Predicting the equilibrium ordered structures at internal interfaces, especially in the case of nanometer-scale chemical heterogeneities, is an ongoing challenge in materials science. In this study, we established an ab-initio coarse-grained modeling technique for describing the phase-like behavior of a close-packed stacking-fault-type interface containing solute nanoclusters, which undergo a two-dimensional disorder-order transition, depending on the temperature and composition. Notably, this approach can predict the two-dimensional medium-range ordering in the nanocluster arrays realized in Mg-based alloys, in a manner consistent with scanning tunneling microscopy-based measurements. We predicted that the repulsively interacting solute-cluster system undergoes a continuous evolution into a highly ordered densely packed morphology while maintaining a high degree of six-fold orientational order, which is attributable mainly to an entropic effect. The uncovered interaction-dependent ordering properties may be useful for the design of nanostructured materials utilizing the self-organization of two-dimensional nanocluster arrays in the close-packed interfaces.
authors.affiliation: Department of Mechanical Science and Bioengineering, Osaka University, Osaka 560-8531, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Kimizuka
authors.affiliation: 1] Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501, Japan [2] Center for Elements Strategy Initiative for Structural Materials, Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Shu
authors.initials: S
authors.lastname: Kurokawa
authors.affiliation: Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yamaguchi
authors.affiliation: Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Sakai
authors.affiliation: 1] Department of Mechanical Science and Bioengineering, Osaka University, Osaka 560-8531, Japan [2] Center for Elements Strategy Initiative for Structural Materials, Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Ogata