Crack-formation phenomena near vickers indentation in chemically and thermally pretreated sodium-silica glasses

Mechanical characteristics of solids are frequently determined by the state of veridual stresses in the near-surface region. As has been shown previosly the determination of the critical load for crack initiation during Vickers hardness indentation testing can be applied to measure these stresses. In the work reported, this procedure was exploited to study silver ion-exchanged soda-lime silica glasses which are investing because of their optical properties. It was found that in composition with potassium ions the stress induced by colloidal silver is rather small. The hinonhamogeneous distribution of silver particles and the large polarizability of silver ions are probably responsible for complicated stress relaxation processes and stress profiles.