Microstructure and fracture toughness of graphene nanosheets/alumina composites

Graphene nanosheets (GNS)/alumina composites were fabricated by hot pressing. The microstructure and mechanical properties are apparently influenced by the addition of GNS. In particular, the fracture toughness of the composites improves notably. The maximum value is 6.6 MPa m1/2 for the 0.2 wt% GNS/alumina composite, which is about 43.5% higher than that of the monolithic. The main toughening mechanisms are crack deflection, crack bridging, crack branching and the pullout of GNS.