Enhancement in nanohardness of soda–lime–silica glass

For a thin commercial soda–lime–silica glass cover slip a significant increase in nanohardness (e.g. up to 74%) occurred with variations in the loading rate (10–20,000μN·s−1) along with presence of serrations in load–depth plots and deformation band formation inside the nanoindentation cavity. These results are explained in terms of shear stress acting at positions of structural weakness close to the tip of the nanoindenter and the time scale of interaction between the nanoindenter and the local microstructure of the glass. ► Improvement in nanohardness of soda-lime-silica glass cover slip with loading rate. ► Presence of shear induced serrations in load-depth plots. ► Number of serrations depend on loading rate. ► Shear induced flow due to local weakness provided by network modifiers. ► Shear band observed inside the nanoindentation cavity by scanning probe microscopy.