An investigation of high-temperature deformation strengthening and toughening mechanism of titanium alloy

The high-temperature deformation strengthening and toughening mechanisms have been investigated. It is found that equiaxed alpha phases in tri-modal microstructure have no inherent orientaion with transformed beta matrix, dislocations can easily find their slip plane, so they give coordination of materials' deformation, and result in higher ductility. The striature alpha phases not only increase the strength and creep properties, but also change the cracks' propagation directions, thus cracks make a more winding way along or cross grain boundary between striature alpha phases, and materials show a higher fracture toughness. This new deformation theory applies to α, near α, (α+β) and β titanium alloys.