Topological models of yttrium aluminosilicate glass based on molecular dynamics and structure characterization analysis

Abstract

Topological constraint theory (TCT) and molecular dynamics simulations (MD) are utilized to study the effect of Y₂O₃/SiO₂ substitution on the short- and medium-range structures and properties in aluminosilicate glasses containing Y₂O₃. Experimental methods have been applied to characterize the structures of the as-prepared glasses to verify the accuracy of MD simulations. It was found that the Y–O bond distance is around 2.38 Å and the Y average coordination number is around 5.78. The introduction of Y₂O₃ disrupts the Si–O and Al–O bonds in the network structure and elevates the proportion of non-bridging oxygen. Meanwhile, the calculation results of Si–O and Al–O bond distances show Y shortens the distance between Si, Al cations and oxygen ions, improving the network structure tightness. Furthermore, the glass transition temperature (T_g), Vickers hardness (H_V), and elastic modulus (E) of glass increase with the increase of Y₂O₃ content, while the viscosity decreases. TCT was used to analyze the relationship among glass compositions, structures, and properties, and the properties prediction models for T_g, H_V, and E were established. The effectiveness of TCT prediction models was proved by the comparison between the results predicted by the models and the data reported in the literature.