Characterization of Particle Impact Damage and Residual Strength Degradation Behaviors in Structural Ceramics

In order to characterize particle impact damage in structural ceramics, the damage morphologies and the resulting strength degradation behaviors were investigated for silicon carbide and silicon nitride, using particles of different hardness. The types of damage induced in each specimen were closely related to the deformation behavior at the impact site. Particle impact damage could be characterized by the deformation behaviors, such as Hertzian cone cracks in the case of silicon carbide showing nearly elastic deformation and median cracks in the case of silicon nitride representing significant plastic deformation. Silicon nitride showed a somehow higher resistance for particle impact damage compared with silicon carbide. The effects of the particle hardness on the extent of damage and the residual strength degradation were significant in the case of silicon nitride but slight in the case of silicon carbide. The residual strength after impact test had a good correlation with the characterized crack size.