Toughening mechanisms and microstructure of Al2O3–TiC–Co composites

Cobalt-coated Al2O3–TiC composites were prepared by hot-pressing at 1650 °C. Higher fracture toughness (7.81 MPa m1/2) and bending strength (782 MPa) were obtained for composites containing both intragranular and intergranular TiC grains. TiC grains were dispersed homogeneously with an incoherent interface in the Al2O3 matrix and most cobalt particles resided at triple grain junctions. Grain/subgrain refinement, dislocation activities, and dispersion strengthening mainly account for the toughening mechanisms.