Microstructural characteristics and texture evolution of Ti-6Al-4V-0.55Fe alloy during isothermal multi-stage hot compression

In this study, an isothermal multi-stage hot compression was employed at temperatures of 890°C, 920°C, 950°C, and 990°C to investigate dynamic recrystallization, α→β transformation (DT), and texture evolution in the α+ β phase region of the Ti-6Al-4V-0.55Fe alloy. The results demonstrate that the flow stress decreases with increasing deformation temperature and strain degree, indicating pronounced flow softening. During isothermal multi-stage hot compression at 920°C, discontinuous dynamic recrystallization (DDRX) consistently occurs; however, continuous dynamic recrystallization (CDRX) initiates at a strain of 0.4. At high strain, spheroidized α grains with higher stored energy achieve clustering by consuming dislocations at common grain boundaries, ultimately form irregular α phases. After isothermal multi-stage hot compression at 950°C, a pronounced DT is observed. The lamellar α phases undergo kinking, which promotes α-phase spheroidization and DRX through lattice rotation. Furthermore, the lamellar α phases are refined by shear separation. With the deformation temperature and strain increase, the HCP slip was predominantly completed by pyramidal <c+a> slip systems, and the {101̅0}< 112̅0 > slip system gradually weaken, leading to the initial < 101̅0 > //Z0 texture progressively transforms into < 0001 > //Z0 texture.