Fracture of severely plastically deformed titanium

The mechanical properties with emphasis on the fracture behaviour of ultrafine-grained Ti processed by high pressure torsion were evaluated. Through this process a substantial refinement of the microstructure was induced. As a consequence, a pronounced increase of tensile strength was achieved compared to conventional Ti while the ductility exhibited only a minor reduction after processing. The fracture toughness in terms of the critical stress intensity factor and crack tip opening displacement was evaluated in different crack growth directions and showed a pronounced orientation dependency, which can be related to the typically elongated microstructure induced by this deformation method.