Contact residual stress relaxation in soda-lime glass: Part I. Measurement using nanoindentation

The contact residual stress field created by a Vickers indentation is a micro-size region of high and varying stresses. Stress relaxation studies in such a micro-region may not be accessible to the conventional methods of investigation. In this paper the elastic response during nanoindentation has been used to study the isothermal stress relaxation of a Vickers residual stress field in soda-lime glass at 540 and 630 °C. At each temperature, the stress relaxation profile varied from one location of the stress field to the other suggesting non-linear response to stress. Also, the relaxation profiles at identical positions were different for the two temperatures suggesting that the Vickers residual stress field is not a thermorheologically simple region of material.