CHARACTERIZATION OF GLASSES AND CERAMICS BY CONTINUOUS INDENTATION TESTS

Continuous indentation tests were performed on soda lime silica glasses and tetragonal zirconia polycrystal ceramic samples containing 10-14 mol% CeO2 (Ce-TZP ceramics) to determine their Vickers hardness (HV) and fracture toughness (K-IC). The load-indentation depth curves were taken during the loading as well as the unloading period by a computer controlled MTS machine. It was found that the loading force is a quadratic function of the indentation depth during both the loading and unloading stage of the deformation. Using the HV values and the measured length of the cracks the K-IC values were calculated. The fracture toughness of Ce-TZP ceramic samples decreases with increasing CeO2 content as a consequence of the reduced transformability of the tetragonal phase.