Atomic Ordering and Interfacial Interaction at Liquid-Mg/SiC{0 0 0 1} Interfaces: An Ab Initio Molecular Dynamics Study

Abstract

We present the results of ab initio molecular dynamics investigations on the atomic ordering and chemical interactions at the interfaces between liquid Mg and SiC{0 0 0 1} interfaces. The simulations reveal distinct borders between the SiC substrates and liquid Mg. The liquid Mg atoms adjacent to the substrates are bonded to the outmost C/Si atoms and are positively charged. The terminating Mg layers contain a variety of atomic vacancies, being topologically rough. The liquid Mg atoms adjacent to the substrates display unusual prenucleation phenomenon with strong layering but weak in-plane ordering. The obtained information here is helpful to get insight into the formation and interfacial interactions in the SiC joined nano-sized magnesium matrix composites and the role of SiC particles as potential nucleation sites during solidification, and further helps understand interfacial interactions at the grain boundaries in ceramic/metal composites and welded parts, etc. in general.