3D analysis of crack morphologies in silicate glass using FIB tomography

The surface damage and induced cracks around Vickers indents in soda-lime-silicate glass have been examined for the first time in 3D by cross-sectioning the indents using a highly focused ion beam (FIB). The 3D FIB tomographic analysis determines quantitatively both the location and 3D shape of individual cracks within a cluster around an indentation, and the 3D FIB technique will be applicable to analyse other types of surface damage in amorphous materials. For silicate glass it is shown that increasing the applied indent load from 50 to 200 g, results in a significant increase in measured crack density and 3D interconnections. It is also observed that the planar FIB cross-section surfaces cut through the very centre of the indents can undergo time-dependant strain and bulge outwards in order to relieve high local residual stresses.