In Situ Cube-Corner Indentation Of Soda-Lime Glass And Fused Silica

Indentation fracture with a cube-corner diamond pyramid on soda-lime silicate glass and fused silica is investigated during the entire indentation cycle in both silicone oil and ambient-air environments. Radial cracks form immediately on loading in all cases. The two-component, elastic-contact + elastic-plastic mismatch stress field model that has been used successfully to describe radial crack evolution at Vickers indentations fails to describe the fracture response with the cube-corner. The amplitudes of both elastic-contact and residual stress-intensity factors as deducted from these cube-corner experiments are up to a factor of 10 greater than have been previously observed.