Molecular dynamic simulation has been done to determine the dynamic and local structure of liquid alumina at 3000 K. Fourteen different systems at densities ranging from 2.5 to 4.5 g cm −3 was prepared by compressing the low-density melt. Two kinds of pore aggregation, pore cluster and pore tube, were examined. Clear evidence was found of structural transformation from a tetrahedral to an octahedral network. For a low-density system there was a large pore tube, which involved 93% of oxygen-vacancy-like pores and spread over the whole simulation cell. Conversely, in a high-density system the largest pore tube contained less than 1% of all oxygen-vacancy-like pores. A similar trend also was observed for other pore kinds such as aluminium-vacancy-like pores and large pore clusters. The diffusion constants significantly decreased in the region of the structural transformation. The diffusion mechanism in low-and high-density systems was examined and is discussed here.

No abstract

No abstract

No abstract

No abstract