STRENGTHENING AND TOUGHENING MECHANISMS OF CERAMIC NANOCOMPOSITES

Crack-tip bridging by particles is considered to be one of the primary strengthening mechanisms of ceramic nanocomposites. Small, brittle pa rticulate inclusions have been shown to cause crack-tip bridging at sh ort distances behind the crack tip. This mechanism leads to modest tou ghness but a very steep R-curve, and it is the latter that produces th e very high fracture strength of the ceramic nanocomposite, Localized high residual stress around the particles (particularly in the case of silicon carbide-alumina material) causes the strengthening mechanism to operate effectively, even at a small volume fraction of 5%. The pre sent study predicts the magnitude of the toughness increase and the ex tent of R-curve behavior for the nanocomposite.