Pressure-induced structural variations and mechanical behavior of silicate glasses: Role of aluminum and sodium

Abstract

This study investigates the effects of pressure-induced densification on the structural and mechanical properties of albite-like (12.5 % Na₂O·12.5 % Al₂O₃·75 % SiO₂) and sodium silicate (12.5 % Na₂O·87.5 % SiO₂) glasses using Molecular Dynamics simulations. Densification increased the coordination numbers of Al and Na, facilitated Al-O-Al clustering and formation of three-bridging oxygens, reduced T-O-T angles, and packed sodium ions in albite glass. Sodium silicate glass exhibited densification primarily through increased Na coordination, reduction of Si-O-Si angle and reduced Na-Na distances. Elastic modulus calculations revealed increased stiffness with densification due to enhanced atomic packing and glass reticulation. Uniaxial tensile tests showed densified glasses had higher ductility and strength than undensified counterparts, highlighting the positive effects of pressure-induced structural rearrangements. Hydrostatic compression tests demonstrated reversible densification under varying pressure loads, with pre-treatment conditions significantly affecting residual densification.