Comparison of Potentials in Molecular Dynamics Study of the Al/Sic Interface at High Temperatures

Abstract

We used molecular dynamics to simulate the interface diffusion and reaction behavior of Al/SiC composite at temperatures above the melting of the Al. The interfacial evolution, surface polarity and the wettability were examined by different hybrids of potentials that widely used in the simulations of metal-ceramic system. We demonstrated that the results from hybrids of potentials for the Al/SiC system that commonly used are inconsistent with experiments of the interfacial properties at high temperatures. The hybrids of the embedded atom method (EAM) potentials for Al with Tersoff-type potentials or the modified embedded atom method (MEAM) potential for the SiC show that the interface almost inert at 1200 to 1500 K. The combinations of Al potentials with Vashishta potential for SiC appear to give a more realistic description of the diffusion and reaction at Al/SiC interface, but still has shortcomings as diffusion also occurs at temperatures well below the melting point of Al. For the wetting behavior, the hybrids of EAM potential developed by Mendelev et al. for Al exhibit the largest contact angle among the potentials. The influence of surface polarity of the SiC on the wettability is weakened after a long enough time. The reaction products (e.g., Al4C3) and the influence on wetting at the interface may not be well characterized since the interaction of Al-C and Al-Si are only described by a pair potential. Our study provides support for molecular dynamics study of the Al/SiC system involving high temperature conditions.

Keywords: Al/SiC interface, wetting, diffusion, reaction, Molecular dynamics (MD)