Structural Transformations and Mechanical Properties of Porous Glasses Under Compressive Loading

The role of porous structure and glass density in the response behavior to compressive deformation of amorphous materials is investigated via molecular dynamics simulations. The disordered, porous structures were prepared by quenching a high-temperature binary mixture below the glass transition point into the phase coexistence region. With decreasing average glass density, the pore morphology in quiescent samples varies from a random distribution of compact voids to complex pore networks embedded in a continuous glass phase. We find that during compressive loading at constant volume, the porous structure is linearly transformed in the elastic regime and the elastic modulus follows a power-law increase as a function of the average glass density. Upon further compression, pores deform significantly and coalesce into large voids leading to formation of domains with nearly homogeneous glass phase, which provides an enhanced resistance to deformation at high strain.