ATZ Composites Resistant to Subcritical Crack Propagation
Agnieszka Wojteczko, Marek Grabowy, Alan Wilmański, Sebastian Komarek, Dawid Kozień, Waldemar Pyda, Rosa Maria Pena Capote, Zbigniew Pędzich
Quarterly No. 3, 2024 pages 194-199
DOI: https://doi.org/10.62753/ctp.2024.05.3.3
keywords: particulate composites, zirconia, alumina, fracture toughness, subcritical crack propagation
abstract ATZ (alumina toughened zirconia) particulate composites are materials which utilize the phenomenon of residual thermal stresses arising during cooling from the sintering temperature to normal conditions. Since the stresses in zirconium dioxide grains are tensile, they increase the susceptibility to transformation of the tetragonal phase into the monoclinic one, a phenomenon which is used to strengthen the material, i.e. to increase its resistance to cracking. The paper presents the results of research on composites that were manufactured by means of special technology using the sintering of a mixture of ZrO2 powders with various contents of the stabilizing oxide Y2O3. These materials, thanks to a significant reduction in grain size, demonstrate excellent mechanical parameters, strength and resistance to brittle fracture. Moreover, it was found that incorporating alumina grains in the zirconia matrix can cause the distribution of stress to significantly reduce the tendency to subcritical cracking, which is a high risk for oxide ceramics. It was found that for some ATZ composites the phenomenon of subcritical cracking was inhibited in both air and water environments.