Temperature-dependent oxidation kinetics and mechanical properties degradation of Cf/ZrB2-SiC composites

The oxidation kinetics and microstructures evolution of Cf/ZrB2-SiC composites are investigated by experimental characterizations. An empirical model containing multi-reaction systems is further established for predicting the specimen mass evolution during isothermal oxidantion. Based on the morphological observations and in-situ tensile responses, three oxidation mechanisms of carbon phase controlled by reaction and diffusion kinetic are categorized as uniform, non-uniform and superficial oxidation. The relationship between fracture modes and internal fibers microstructures indicates that the structural origin of the fracture mode transition is the toughening mechanism transition of fibers on the ceramics matrix induced by oxidative damage.

Automated summary

The oxidation kinetics and microstructural evolution of Cf/ZrB2-SiC composites are studied, and an empirical model is established for predicting the oxidation behavior. Three oxidation mechanisms of carbon phase controlled by reaction and diffusion kinetics, categorized as uniform, non-uniform, and superficial oxidation, are identified based on morphology observations and in-situ tensile responses. The relationship between fracture modes and internal fiber microstructures suggests that the toughening mechanism transition induced by oxidative damage is the structural origin of the fracture mode transition.