Fabrication of alumina-based toughened nanocomposites

Highly toughened nickel dispersed alumina-based nanocomposites were fabricated using our developed soaking method, based on our previously proposed toughening mechanism of nanocomposites. Commercially available gamma-alumina agglomerate with high porosity was used as a starting material. Nickel nitrate solution was penetrated into the nano-pores of the gamma-alumina agglomerate using this new technique. The alumina-nickel composite powder with alpha-alumina seeds was then sintered using a pulse electric current sintering technique. To disperse dislocations generated around the nano-particles into alumina grains, the sintered materials were annealed. The results showed that the maximum fracture toughness was 7.6 MPam(1/2), which was about two times higher than that of dense alumina.