Modeling the effect of composition and thermal quenching on the fracture behavior of borosilicate glass

This article describes the fracture processes simulated by classical molecular dynamics in three alkali borosilicate glasses of different compositions. Applying an external tensile load results in glass fracturing through processes of nucleation, growth, and coalescence of cavities. The cavity nucleation processes begin during the elastic phase and differ depending on the glass composition and especially on the [Na ₂O]/[B ₂O ₃] ratio. The cavity growth and coalescence phases are associated with the plastic phase. The concentration of BO ₃ entities has a strong influence on the cavity growth rate because these entities limit the accumulation of local stresses. Glass specimens with the same compositions but disordered by the application of a higher quenching rate were also fractured. These glasses are considered as models of irradiated structures and analyzing their fracture behaviors gives interesting information as to the understanding on why the fracture toughness evolves under irradiation.