EFFECT OF THE CaO-MgO-Al2O3-SiO2 GLASS COMPOSITION ON THE MICROSTRUCTURE AND RHEOLOGICAL PROPERTIES FROM A MOLECULAR DYNAMICS SIMULATION

Abstract

By adjusting the ratio of SiO2 /RO (R=Ca, Mg), this article studied the atomic structure of CaO-MgO-Al2O3-SiO2 glassy melts by a molecular dynamics simulation. The Pair distribution function (PDF), Coordination number (CN), bridging oxygen (BO), non-bridging oxygen (NBO), and Qn were utilised to characterise the glass structure. The results indicated that the content of the bridging oxygen was decreased with the RO replacing the SiO2. The total content of Q4 in the tetrahedron changed significantly from 34.11 % to 18.06 %. Meanwhile, the NBO/T parameter increased from 1.298 to 1.555. In the corresponding viscosity test, the melting temperature, fitted by the MYEGA equation, also decreased with the decrease in the SiO2 content, and the fragility value increased from 39.12 to 53.20. Finally, the fragility and NBO/T were linked to describing the relationship between the mid-range structure and the rheological property. Moreover, the analyses showed that they had a linear relationship.