Vitreous 2D silica under tension: From brittle to ductile behaviour

Abstract

Based on measured ring size distributions of real 2D silica, we numerically prepare sample sets of vitreous 2D silica with varying network topology. We use a Monte Carlo bond-switching method to apply a sequence of topological flip transformations to initially hexagonal 2D silica. In doing so, we are able to control the network heterogeneity by means of the ring size distribution. This method also enables physically meaningful ring neighbourhood statistics according to the empirical Aboav-Weaire law. The obtained vitreous 2D silica sample sets undergo athermal quasistatic tensile deformation in order to investigate the changes of the mechanical behaviour as a function of the underlying network heterogeneity. The molecular statics simulations reveal that the ductility and tensile strength of 2D silica can significantly be tuned varying the network ring statistics. Furthermore, the stress-drop statistics of the respective sample sets are evaluated and shown to display a self-organised critical behaviour.