Influence of ultra-high residual compressive stress on the static and dynamic indentation response of a chemically strengthened glass

The influence of ultra-high surface compressive stresses (∼1 GPa) on the static and dynamic indentation response was investigated on an ion-exchanged glass and compared with the raw glass properties. Static hardness measurements were conducted utilizing a standard Vickers hardness tester (15 s duration), while dynamic hardness measurements were performed using a custom-made dynamic indentation hardness tester (60 μs duration). It was found that there is an 11% increase in static and dynamic hardness from the raw glass to the strengthened glass due to chemical strengthening. The dynamic hardness on the strengthened glass was also 23% greater than the static hardness. Additionally, the strengthened glass exhibited notable radial crack suppression. To examine the subsurface hardness profile, static Vickers indentations were conducted on a lateral surface which was polished to remove the strengthened layer. The hardness profile revealed that the effect of strengthening extended to 3 times the case-depth measured using photoelasticity.