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

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.