Determination of the Fracture Toughness of Glasses via Scratch Tests with a Vickers Indenter

Abstract

Fracture toughness is an important index in safety evaluation for materials and structures. Its convenient and accurate characterization has attracted extensive attention. For small specimens, traditional testing methods of fracture toughness are not suitable due to limitations in sample size and shape. In this work, a new formula is proposed to determine the fracture toughness of glasses using scratch tests with a Vickers indenter based on dimensional analysis and finite element analysis. Fracture toughness of glasses could be calculated with elastic modulus, crack depth of scratched materials and normal force applied during the scratch tests. The effects of plastic deformation and interfacial friction between the Vickers indenter and scratched materials are considered, and the crack shape is consistent with experimental observations. The proposed formula is verified by comparing the fracture toughness of soda-lime and borosilicate glasses obtained from scratch tests with those obtained via indentation tests. This work provides an alternative method to determine the fracture toughness of glass materials.