Ab-initio molecular dynamics study of heterogeneous nucleation at the liquid-Y/α-Al2O3 interface

Abstract

We have investigated the heterogeneous nucleation phenomenon of rare earth metal Yttrium on the surface of alumina. The liquid Y/α-Al2O3 interface was studied at different temperatures and different configured substrates using ab-initio molecular dynamics simulations. The results show that liquid Y atoms near the substrate can form several ordered atomic layers at temperatures slightly above the liquidus of Y, implying occurrence of prenucleation. Although the liquid atoms become slightly less ordered as the temperature rises, the ordered layers are still present. The chemical interaction has a higher impact on the nucleation of metal Y than the temperature, where the oxygen-terminated substrate is more favorable to the nucleation of rare earth Y. The increasing ordered first layer of liquid atoms can promote the following nucleation. We also reveal the effect of the oxide substrate on the heterogeneous nucleation at the liquid-solid interface. The results obtained are useful to deepen our understanding of the behavior of liquid rare earth metal interfaced with α-Al2O3.