Flow behavior and dynamic recrystallization mechanisms in thermomechanical processing of a near β titanium alloy

This study provides a comprehensive analysis of the flow behavior and dynamic recrystallization (DRX) of the Ti7333 alloy under various thermomechanical processing conditions. Hot compression experiments are performed over a temperature range of 770 degrees C to 920 degrees C and strain rates ranging from 0.001 s-1 to 1 s-1 with true strain of 0.91. Microstructural characterization reveals that the main deformation mechanisms of the (3 phase in the Ti7333 alloy are dynamic recovery (DRV) and DRX. The results demonstrate that discontinuous dynamic recrystallization (DDRX) is marked by the development of bulging grain boundaries and the formation of recrystallized grains, while continuous dynamic recrystallization (CDRX) plays a significant role in reducing dislocation density and promoting microstructural homogeneity. High temperatures and low strain rates improve the DRX fraction with a maximum up to 43.64 % with the average size of 32.7 mu m compared with 76.8 mu m in initial microstructure. To describe the DRX behavior of the (3 phase under hot deformation, the study employs an Arrhenius strain-compensated constitutive equation integrated with microstructure evolution models. Additionally, finite element simulations are used to predict the microstructural evolution during hot compression. A strong correlation is observed between simulated and experimental grain sizes of the (3 phase, validating the accuracy of the model. These findings enhance the understanding of hot deformation mechanisms in near (3 titanium alloys and provide a robust predictive framework for microstructural evolution during thermomechanical processing.