Title: Atomic ordering at liquid-metal or oxide interfaces from Ab initio modelling

Abstract

Oxide particles, magnesia, spinel and alumina are formed in the liquid light metals inevitably during liquid metal dealing and casting. They play an important role in determination of the properties of the cast parts, and may also act as potential nucleation sites to achieve effective grain refinement. Thus, understanding of the atomic ordering at liquid-metal/oxide (L-M/oxide) interfaces is a prerequisite for controlling the heterogeneous nucleation during casting. Here, we briefly overview recent studies devoting to improve the understanding of atomic ordering at the liquid-metal/oxide interfaces from ab initio molecular dynamics (AIMD) simulations. We identified a formed metal layer terminating the oxide substrates, MgO {1 1 1}, α-Al2O3 {0 0 0 1}, MgAl2O4 {1 1 1} and γ-Al2O3 {1 1 1} in the liquid metals. The liquid metal atoms near the interfaces exhibit atomic ordering, as shown in Fig.1 for L-Al/spinel {1 1 1} as an example. The terminating metal atoms exhibit unusual chemistry: being positively charged and topologically rough, which impact strongly the atomic ordering at the interfaces. The obtained information is helpful not only for obtaining insight into the potency of the oxide particles, further for controlling of the solidification, but also for better understanding of ceramic coating of metals and of metal/oxide composite materials.