Abstract
The fracture behaviour (fracture mechanisms, fracture toughness, and strength) of yttria-partially stabilized zirconia (Y-PSZ) single crystals has been investigated between room temperature and 1700 °C. Cleavage was the fracture mechanism acting over the entire temperature interval studied, with some plastic elements arising at temperatures of 1000 °C and above, accounting for the increasing fragmentation with temperature observed for the precipitationhardened materials. Fragmentation is ensured from interdomain cleavage on {1 0 0} and {1 1 0} planes. No subcritical cracks were observed. The strength and fracture toughness follow behaviour typical for materials with a pronounced brittle-to-ductile transition. After a gradual decrease between room temperature and 1000 °C, both properties show a sharp increase under elevated temperatures, followed by a sharp decrease. This increase is associated with dislocation plasticity revealed in delaminations along {1 1 0} and {1 0 0} planes. The lower temperature limit of the brittle-to-ductile transition was estimated as 1000 °C. A higher limit was not reached and the transition of Y-PSZ [1 0 0] single crystals into a ductile state probably occurs at about 2000–2100 °C. The mechanism of ductile fracture is presumably intergranular sliding of grains, formed in the course of plastic deformation, from domain microstructure.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have