The interplay relationship between phase transformation and deformation behavior during hot compression in a metastable β titanium alloy

In this work, the hot compression behavior at 600 °C of a metastable β titanium alloy is investigated to resolve the correlation between phase transformation and deformation behavior. It is demonstrated that the deformation behavior includes a near linear hardening stage, a discontinuous yielding stage, a hardening stage and a final softening stage. For the near linear hardening stage, the α precipitates are formed on the grain boundaries (α_GB). The hardening behavior of the alloy in this stage balanced by boundary hardening through the formation of α_GB. For the discontinuous yielding stage, the softening of deformation behavior is originated from the fragmentation of the α_GB and the generation and movement of mobile dislocation. For the hardening stage follow the discontinuous yielding, the massive β to α phase transformation were occurred and mainly contributed to the hardening behavior. For the final softening behavior stage, three activities: the formation of deformation bands, the spheroidization of α phase and the dislocation slips contribute to the softening behavior. The present results provide comprehensive information on hot deformation mechanisms of metastable β titanium alloys.