EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

One of the main issues about characterizing zirconia-based composites incorporating graphene-based nanomaterials (GBN) is the measurement of their fracture toughness. While indentation methods have been widely used to determine fracture toughness in ceramic materials, they are not of great value when ceramic-based composites, especially zirconia-based, need to be characterized. The Single Edge V-notch Beam (SEVNB) method is a more reliable technique to carry out these measurements. Moreover, this type of notched-specimens also allows to study the slow crack growth resistance (R-curve) of the composites. Despite these facts, many authors still use the indentation method because of the complexity of SEVNB test, which requires the fabrication and machining of notched specimens. Hence, the mechanisms that control the reinforcement in zirconia matrix composites with GBN have not yet been elucidated.

In this work, R-curve behaviour of few layered graphene (FLG)/3Y-TZP composites was characterized in order to better understand in what ways the FLG may improve the ceramic crack growth resistance. To do so, we have followed the crack propagation path during a slow crack growth resistance experiment by means of optical and scanning electron microscopies. Here we present the microstructural analysis and discuss the different mechanisms that could contribute to an increase in the R-curve behaviour in such composites.