Determination of the Intrinsic Fracture Toughness from the Cod Analysis of Indentation Cracks in Spark Plasma Sintered 3y-tzp Reinforced with Mwcnt

The indentation method has been widely used to measure the fracture toughness in fragile materials due to its simplicity and that only needs of a small sample. However, it is well known that the fracture toughness values obtained by indentation methods can be substantially different from the values obtained from more rigorous methods which are based on a precise knowledge of all parameters involved in fracture. This situation has lead to the development of new methods that investigate the crack opening displacement (COD) and relate it to the intrinsic fracture toughness KI0. In the present work, a 3Y-TZP ceramic has been studied together with a composite containing 2 % vol. of multiwall carbon nanotubes (MWCNT); both of which were produced by Spark Plasma Sintering (SPS). The COD method showed that the addition of MWCNTs did not effectively affect the COD and the intrinsic fracture toughness KI0 was thus very similar in both materials. These observations in principle do not justify the differences determined by the classical indentation fracture toughness method on the present materials. PALABRAS CLAVE: Cerámicas, Resistencia, Biomateriales