Local microstructure of liquid and amorphous Al2O3

We present a local microstructure study of liquid and amorphous alumina by means of a molecular dynamic method. The simulation was performed on systems prepared at five different densities and at temperatures from 400 to 800 K for amorphous glass and at 3000 K for liquid. The local microstructure has been analyzed through the pair radial distribution function, bond-angle distribution and the characteristics of voids and void aggregations. We focused on two kinds of void aggregations: void clusters and void tubes. The results showed that many voids clustered nearby and created a very large cavity with volume five times bigger than volume of the aluminum atom. In addition, we found a void tube in low-density systems, which consisted of 75% of all voids and spread over the entire system. The diffusion mechanism in low-density and high-density systems has also been discussed and presented here.