New observations on scratch deformations of soda lime silica glass

In spite of the wealth of literature, the role of the scratching speed in affecting the material removal mechanism in soda lime silica (SLS) glass is yet to be comprehensively understood. Here we report the surface and sub-surface deformation mechanisms of SLS glass scratched under three different normal loads of 5,10 and 15 N at various speeds in the range of 100-1000 mu m/s with a diamond indenter of similar to 200 mu m tip radius. The results show that at any given applied normal load, the width, depth, wear volume of the scratch grooves and wear rate of the SLS glass decreased with an inverse power law dependence on the applied scratching speed. The surface damage also reduced with the increase in scratching speed. A new, simple model was developed to explain these observations. The significant contributions of the time of contact, the tensile stress behind the indenter and the shear stress active just underneath the indenter in governing the material removal mechanisms of the SLS glass were discussed. (C) 2012 Elsevier B.V. All rights reserved.