Effects of microstructure on the cracking behaviors in the lithium aluminosilicate glass ceramics: A statistical analysis

The cracking behaviors of transparent glass ceramics have attracted much attention due to the application as a cover material for smartphones, and it is beneficial to fundamentally understand their origin. In this study, the cracks were induced by scratch and indentation, and their occurrence has been analyzed according to the Weibull’s statistical model. The roles of microstructure on the initiations and propagations of cracks were discussed in terms of modeling parameters, which provided hints for the cracking mechanisms. Overall, it was found that crystallization contributed to the formation of cracks, which seems to be inconsistent with the common sense that crystallites in glass ceramics hinder the cracking. According to the statistical analysis, the critical stress or load for crack initiation is suggested to drop due to the residual stress introduced by crystallization, while the crack propagation is still impeded by the crystalline phases and brings up the fracture toughness (K_IC).