Vickers indentation fracture toughness of Y-TZP dental ceramics

Abstract

The purpose of this study was to investigate and analyse the fracture toughness of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) dental ceramics by means of the Vickers indentation technique. Indentation tests are commonly used for the evaluation of the fracture toughness of brittle materials, particularly glass and ceramics, because this technique requires a small sample from which a large number of data points can be generated rapidly. However, a wide variety of equations for the evaluation of the fracture toughness by means of Vickers indentation are available. Therefore, it is important to choose the most appropriate model for the description of this ceramics' fracture behavior. In the present work, nine different fracture toughness equations are considered and the results are compared with the literature value obtained by a conventional method, single edge V-notched beam (SEVNB) test. The influence of the applied indentation load on fracture toughness was also observed. Tests were conducted under four different loading conditions (29.42N, 49.03N, 196.13N, and 294.20N). Obtained results indicate that the fracture toughness of Y-TZP dental ceramics depends on the indentation load, morphology of indentation cracking as well as on the applied model of fracture resistance.