Features of Deformation Behaviour of α plus β-Titanium Alloys Synthesized by Powder Metallurgy Methods

The factors, which are controlling plastic deformation, strengthening and development of dislocation structure up to fracture during active tensile process in alpha + beta (Ti-6Al-4V) and pseudo-beta (Ti-5Al-5V-5Mo-3Cr, Ti-10V-2Fe-3Al) titanium alloys fabricated by casting and by powder metallurgy, are studied. Independently on porosity and volume content of beta-phase, deformation is controlled by passing of dislocations across thin layers of extended second phases, which inhibit both active and cross slip up to the moment of attainment of critical local stress in slip plane on the interphase boundaries. The plastic deformation and dislocation-structure evolution mechanisms are well identified in these alloys from the reconstruction of the real-stress real-strain diagrams.