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The behavior of a VTI-4 (Ti–22Al–25Nb) alloy during hot compression at a strain rate of ~2.5 s
–1
is studied. Hot compression to a strain of 65% is carried out in the temperature range 850–1020°C, covering two phase regions β + Ο and β + α
2
. Hot compression results in the dissolution and spheroidization of lamellar O and α
2
phases in the severe deformation zone. X-ray diffraction analysis does not reveal any qualitative changes in the phase composition after deformation. Energy dispersive X-ray spectroscopy (EDS) analysis conducted on a transmission electron microscope indicates niobium depletion of the O phase when the hot compression temperature increases or during compression. Niobium-depleted zones form near interphase boundaries during the dissolution and spheroidization of lamellar-shaped O and α
2
phases. The dissolution and spheroidization process includes two stages. The first stage involves defect accumulation in the O-phase and α
2
-phase lattices, and it is accompanied by a simultaneous increase in the temperature due to deformation-induced heating. The second stage icludes niobium redistribution between the β matrix and the phase in defective sites, which leads to phase dissolution and spheroidization.