Abstract:
The alpha/beta titanium alloys Ti-6Al-4V and Ti-6Al-4V-0.75Mo-0.5Fe were heat treated to produce a stable colony microstructure and were compressed in air at a nominal strain rate of 10-3 s-1 to a height reduction of 25, 50, or 70$\%$ at $800^{\circ}C$. Microstructure evolution and mechanical behavior of alpha/beta Ti- 6Al-4V and Ti-6Al-4V-0.75Mo-0.5Fe titanium alloys during uniaxial compression was studied. The plasticflow response for both alloys is characterized by successive stages of strain hardening, flow softening, and steadystate flow. A higher content of beta stabilizers in Ti-6Al-4V-0.75Mo-0.5Fe alloy results in a higher percentage of the beta phase, thicker alpha lamellae and greater mismatch between the alpha and beta lattices. During compression the lamellae spheroidized to produce a partially or entirely globular microstructure. Specifically globularization of the Ti-6Al-4V-0.75Mo-0.5Fe microstructure was faster, that can be associated with easer loss of the initial Burgerstype coherency between the alpha and beta phases and the subsequent individual deformation of each phase. As a result after 70
