Yttrium segregation induced grain growth inhibition during recrystallisation in binary titanium alloys

In the present study, the influence of yttrium addition in titanium was systematically investigated under tensile loading at room temperature. A series of thermomechanical treatments was carried out to produce Pure-Ti, Ti-0.1Y, Ti-0.5Y, Ti–1Y and Ti–3Y alloys. The annealing temperature was adjusted to figure out the effect of grain growth inhibition on Ti-xY alloys during recrystallisation. An increase of yttrium concentration effectively enhances the resistance to grain growth. The mechanism of grain growth inhibition was clearly revealed as yttrium segregation at grain boundary observed by atom probe tomography (APT). The weakened texture and its effect on the deformation behaviour was discussed in terms of the change in grain size. The mechanical properties including yield strength, tensile strength and total elongation were well consistent with the microstructural trend with respect to the variation of the grain size, though a significant drop of total elongation was unexpectedly observed in the samples annealed at 850 °C. The possible role of secondary phase particle observed by transmission electron microscopy (TEM) was also discussed in the frame of the existing literature.