Molecular dynamics simulations of the structural properties of Al2O3-based binary systems

• The structure properties of Al2O3-based binary systems were carried out via molecular dynamics simulation.
• The systematic effects of cation field strength of the metal cations on the melt structure were studied.
• Comparisons were done between simulation results and experimental values.

In order to aid the research and development of Al2O3-based mold fluxes, a comprehensive study of the structural properties of Al2O3-based binary systems was carried out via molecular dynamics simulations. The simulation results demonstrated that the structural properties of Al2O3-based binary systems varied with both the Al3 + content and the type of metal cation. The aluminate network becomes more complex with increasing Al2O3 content, and for a given Al2O3 content in different systems, both the Al–O structural disorder and the polymerization degree of the network structure increase as the metal cations become more electronegative. For a given Al2O3 content, the effects of the components on stabilizing the Al–O network is sequenced as K2O > Na2O > CaO > MgO, and the polymerization degree of the structure in different systems follows the order K2O–Al2O3 < Na2O–Al2O3 < CaO–Al2O3 < MgO–Al2O3. In addition, both the metal cations and the oxygen triclusters play a role in the charge compensation of the AlO4 tetrahedron.