Structural transformations in porous glasses under mechanical loading. II. Compression

Abstract

The role of porous structure and glass density in response 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 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 a porous network 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.

Deformation and flow of amorphous solids: Insights from elastoplastic models

“…These deformations are encountered locally whenever volume changes can be neglected; the cone-and-plate, plate-plate, and Taylor-Couette rheometers (Larson, 1999) used to probe the flow of yield-stress fluids fall in this category. For metallic glasses and other hard materials, uniaxial compression tests (i.e., σ(t) = σ(t) 1 0 0 0 in the bulk, with σ(t) < 0) and tension (σ(t) > 0) are often performed (Priezjev and Makeev, 2017).…”