Slow Crack Growth in Zirconia Ceramics with Different Microstructures
Résumé
A review of Slow Crack Growth experiments conducted in the same laboratory with the same technique (Double Torsion) is presented for zirconia ceramics with different microstructures: (i) a single crystal cubic zirconia as a model brittle material, (ii) different 3%mol. Yttria Stabilised TZP ceramics with grain sizes in the range of 0.3 to 1 µm with or without grain boundary glassy phase, (iii) a 10%mol. Ceria Stabilised Zirconia with a grain size of about 2 pm and a very high transformation toughening capability, (iv) a multiplex zirconia based composite. Zirconia materials are susceptible to Slow Crack Growth (SCG) under static stress intensity factors even much lower than the toughness K1c. The analysis of the crack velocity versus stress intensity factor (V-K1) law shows that SCG is driven by a stress assisted corrosion at the crack tip. The crack resistance increases with the transformation toughening capability: a shift toward high stress intensity factors is observed when going from the single crystal to the Y-TZP and then to the Ce-TZP. The presence of an intergranular glassy phase is analysed. Multiplex zirconia based composites exhibit also other reinforcement mechanisms: enlargement of the transformed zone and crack deflection at the interface between the different layers. They present exceptional crack resistance behaviour.
Origine : Fichiers produits par l'(les) auteur(s)
Licence : CC BY NC - Paternité - Pas d'utilisation commerciale
Licence : CC BY NC - Paternité - Pas d'utilisation commerciale
