Enhanced fracture toughness of TiBw/Ti3Al composites with a layered reinforcement distribution

The prospect of combining laminated structure design and tailored reinforcement distribution to toughen brittle materials is investigated. TiBw/Ti3Al-Ti3Al laminated composites consisting of alternating TiBw/Ti3Al and Ti3Al layers were fabricated by reaction annealing of stacked, alternating foils of TiBw/Ti and Al. Enhancement in the fracture toughness is experimentally observed, which is attributed to stress redistribution and stress state change in laminated composites. Theoretical prediction of fracture toughness depending on a shear ligament toughening model agrees well with the experimental value. It is expected that the design strategy can be extended to other brittle intermetallic compounds, such as Ni-Al, Fe-Al, and Nb-Al systems.