Atomistic response of a model silica glass under shear and pressure

Abstract

The Mechanical Response of a Model Silica Glass is studied extensively at the submicrometer scale, with the help of atomistic simulations. The analysis of the response to a hydrostatic compression is compared to recent experimental results. The irreversible behaviour and the variation of intertetrahedral angles is recovered. It is shown that the atomistic response is homogeneous upon compression, in opposition with the localization along shear bands occuring during shear deformation with constant volume. Moreover, the Bulk Modulus anomaly is interpreted as due to a succession of such homogeneous but irreversible atomic rearrangements.

Vibration Modes and Characteristic Length Scales in Amorphous Materials

“…The very high quenching rate (>10 11 K s À1 ) used in atomistic simulations is far larger than the largest experimental quenching rate ($10 6 K s À1 ). However, the numerically obtained equilibrium structure is very close to the experimental one 4 at least for smallscale order as measured by the pair correlation function, suggesting that the classic empirical interatomic interactions used for the calculation implicitly accelerate the relaxational dynamics. 25 This is why a comparison between classic molecular dynamics and experimental measurements is not hopeless and can be used to emphasize the role of the local structure on the mechanical properties.…”

“…In this article, we will take examples from different model amorphous materials obtained in this way and constructed with different empirical interatomic potentials: Lennard-Jones interactions as an example of two-body interactions, 23 StillingerWeber potentials with a set of variable parameters to tune the bond directionality (three-body interactions), 3 and BKS potential with effective Coulomb interactions and two different species that are used to model silica glasses. 4 The variety of these interactions will allow us to underline the role of composition on the elementary processes of the mechanical response.…”

“…These materials have no intrinsic structural length scale despite the interatomic distance, as can be probed by measuring its static structure factor 1 or, equivalently, pair correlation function. It includes amorphous semiconductors like silicon, 2,3 oxide glasses like silica and silicate glasses, 4 metallic glasses, 5 and other disordered assemblies like colloidal glasses. 6 These materials are brittle at large scale but ductile at small scale.…”

Densification as the Only Mechanism at Stake during Indentation of Silica Glass?

“…Yet, in contrast to PID, we assume that shear plays a role in triggering the densification process, which is in agreement with recent molecular dynamics studies [22].…”

Cooling rate and stress relaxation in silica melts and glasses via microsecond molecular dynamics

“…Molecular dynamics (MD) has been extensively used to study silicate glasses [1][2][3] in areas of nanosecond aging of silica [4][5][6], pressure and shear response [7][8][9], and cooling-rate effects [10][11][12][13]. In this work, we use the BKS interatomic potential [14], which has been used frequently to study the glass properties of silica, and has been demonstrated to capture experimentally observed behavior.…”