Discontinuous yield behavior in titanium alloys caused by activated dislocations during tensile testing at room temperature

Discontinuous yield (DY) in titanium alloys at room temperature is revealed for the first time, showing its importance for formulating the deformation process. Titanium alloys with different contents of the β phase and morphology of the α phase were prepared by adding vanadium, and the DY behavior during tensile testing at room temperature was analyzed. The results show that DY is caused by dislocation slip in the primary α (α_p) phase excited by the accumulation of dislocations at the α_p/β phase interface. When the V content increases, the content of β phase increases from 17 to 53.4% and the aspect ratio of α_p phase decreases from 10.1 to 4.3. The difference of hardness and Young's modulus between β and α_p phases increases from 0.08 to 1.39 GPa and 11.18 to 25.72 GPa, respectively. These changes induce the increase of local dislocation density, which leads to DY.