Cavity formation in deformed amorphous solids on the nanoscale

Abstract

Amorphous solids, confined on the nanoscale, are studied using molecular dynamics computer simulation. Unlike in bulk samples, failure patterns in such systems are strongly affected by the confinement geometry and interfacial effects in the sample. We study a confined model glass, subjected to uniaxial loading, for varying aspect ratios of the sample geometry. While for a small aspect ratio, the sample breaks by forming a neck, above a critical value of the aspect ratio, cavitation is seen. The critical aspect ratio is associated with a strain-rate- and temperature-dependent critical curvature of the neck, above which the free energy of the system is minimized by the formation of a cavity. This mechanism of cavity formation is probably a generic mechanism for material's failure in small confined systems under mechanical load.