The influence of periodic shear on structural relaxation and pore redistribution in binary glasses

Abstract

The evolution of porous structure and local density, and associated changes of potential energy in binary glasses under oscillatory shear deformation, are investigated using molecular dynamics simulations. The porous glasses were initially prepared via a rapid thermal quench from the liquid state across the glass transition temperature and allowed to phase separate and solidify at constant volume, thus producing an extended porous network in an amorphous solid material. We find that under periodic shear, the potential energy decreases over consecutive cycles due to gradual rearrangement of the glassy material, and the minimum of the potential energy after thousands of shear cycles is lower at larger strain amplitudes. Moreover, with increasing cycle number, the pore size distributions become more skewed toward larger length scales, where a distinct peak is developed and the peak intensity is enhanced at larger strain amplitudes. The numerical analysis of the local density distribution functions demonstrates that cyclic loading leads to formation of higher density solid domains and homogenization of the regions with reduced density.