Research of Microstructurally Developed Toughening Mechanisms in Ceramics, Part 5. Effect of Temperature and Alloy on Fracture Toughness

摘要

The critical stress intensity factor (Kc) of materials containing tetragonal ZrO2 was found to decrease with increasing temperature and CeO2 alloying additions, as predicted by theory. The temperature dependence of Kc was related to the temperature dependence of the chemical free energy change associated with the tetragonal yields monoclinic transformation. Good agreement with thermodynamic data available for pure ZrO2 was obtained when the size of the transformation zone associated with the crack was equated to the size of the ZrO2 grains. The Kc vs CeO2 addition data was used to estimate the tetragonal, monoclinic, cubic eutectoid temperature of 270 C in the ZrO2-CeO2 binary system. (Author)