2, University of Illinois at Urbana Champaign, Urbana Champaign, Illinois, United States
Molecular dynamics simulations are used to investigate the underlying thermally activated processes contributing to stress relaxation in a model binary amorphous system (J. Mater. Res. 32, 2668 (2017); Acta Mater. 143, 205 (2018)). Depending on the degree to which the amorphous solid is relaxed, significant atomic-scale scale activity is seen well below the glass transition regime, and that this is largely independent of the external load. The observed stress relaxation is mediated by spatially localized and thermally activated structural excitations, which can collectively lead to a global gauge shearing, the location of which correlates with regions of low icosahedral content with lower coordination and higher density.