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The structural evolution and dynamical properties of Al 2 Ag and Al 2 Cu liquids have been investigated in the temperature range of 943–1153 K by synchrotron X-ray diffraction and ab initio molecular dynamics simulations. It is demonstrated that the local atomic packing of Al 2 Ag liquid has lower ordering than the Al 2 Cu liquid, in which Al and Ag atoms are more randomly distributed while Al and Cu atoms tend to form pairs. With decreasing temperature, the bond-angle distributions of Ag Ag Ag and Ag Al Ag triplets shift to 60°, indicating that the local ordering transforms from the icosahedron-like to the hexagonal close-packed structure, while the Cu Cu Cu and Cu Al Cu triplets have the similar angles to those in the crystalline Al 2 Cu compound. These are consistent with the major Voronoi polyhedrons in both liquids. The dynamic results reveal that Al and Ag atoms diffuse much easier in the Al 2 Ag liquid than Al and Cu in the Al 2 Cu liquid, making Al and Ag atoms more randomly distributed and thus reducing the local ordering in the Al 2 Ag liquid. [ABSTRACT FROM AUTHOR]

Structural changes of liquid GaIn eutectic alloy upon cooling from about 373 K to 242 K are studied by using in situ synchrotron radiation X-ray diffraction (XRD) combined with the ab initio molecular dynamics simulations (AIMD). The experimental and theoretical results show that no abnormal structural change is observed in the supercooled liquid region prior to crystallization. The XRD data exhibit that the liquid can crystallize into a mixture of orthorhombic Ga-I and body-centered tetragonal (bct)-In phases. Also, the AIMD calculations simulate the solidification process, forming a bct-like structure locally similar to bct-Ga-III and bct-In phases. The aggregation of In atoms forms In-rich zones, acting as the processor of crystallization. Our results provide an in-depth understanding of liquid GaIn alloys and will trigger more interests to other metallic liquids. • Microstructural evolution of liquid GaIn alloy were studied by XRD and AIMD. • No abnormal structural change was observed in the supercooled liquid upon cooling. • Atomic-scale solidification process was revealed, motivated by In aggregation. [ABSTRACT FROM AUTHOR]