Strengthening and Toughening Mechanisms of Ceramic Nanocomposites

Abstract

Crack‐tip bridging by particles is considered to be one of the primary strengthening mechanisms of ceramic nanocomposites. Small, brittle particulate inclusions have been shown to cause crack‐tip bridging at short distances behind the crack tip. This mechanism leads to modest toughness but a very steep R ‐curve, and it is the latter that produces the 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 present study predicts the magnitude of the toughness increase and the extent of R ‐curve behavior for the nanocomposite.