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

• Molecular dynamics simulations have been used to simulate sodium silicate and aluminosilicate glasses. • The effect of pressure during glass production on the final structure and mechanical properties has been investigated. • The distinct roles of aluminum and sodium has been unraveled. Aluminum strengthens glasses, while sodium acts differently, impacting structures as a compensator or modifier, shaping novel coordination environments. • Uniaxial tensile tests reveals that pre-densified glasses are more ductile than silicates thanks to the possibility of bond-switching during deformation. • Hydrostatic compression tests reveal that densification is largely reversible under varying pressure loads, with pre-treatment conditions significantly influencing residual densification. This study investigates the effects of pressure-induced densification on the structural and mechanical properties of albite-like (12.5 % Na 2 O·12.5 % Al 2 O 3 ·75 % SiO 2 ) and sodium silicate (12.5 % Na 2 O·87.5 % SiO 2 ) 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.