Simulated and experimental investigation on discontinuous dynamic recrystallization of a near-a TA15 titanium alloy during isothermal hot compression in b single-phase field
(State Key Laboratory of Solidification Processing, School of Materials Science and Engineering,
Northwestern Polytechnical University, Xi’an 710072, China)
Northwestern Polytechnical University, Xi’an 710072, China)
Abstract: A cellular automaton (CA) modeling of discontinuous dynamic recrystallization (DDRX) of a near-α Ti-6Al-2Zr-1Mo- 1V (TA15) isothermally compressed in the b single phase field was presented. In the CA model, nucleation of the b-DDRX and the growth of recrystallized grains (re-grains) were considered and visibly simulated by the CA model. The driving force of re-grain growth was provided by dislocation density accumulating around the grain boundaries. To verify the CA model, the predicted flow stress by the CA model was compared with the experimental data. The comparison showed that the average relative errors were 10.2%, 10.1% and 6%, respectively, at 1.0, 0.1 and 0.01 s-1 of 1020 °C, and were 10.2%, 11.35% and 7.5%, respectively, at 1.0, 0.1 and 0.01 s-1 of 1050 °C. The CA model was further applied to predicting the average growth rate, average re-grain size and recrystallization kinetics. The simulated results showed that the average growth rate increases with the increasing strain rate or temperature, while the re-grain size increases with the decreasing strain rate; the volume fraction of recrystallization decreases with the increasing strain rate or decreasing temperature.
Key words: discontinuous dynamic recrystallization; cellular automaton; dislocation density evolution; recrystallization kinetics; TA15 titanium alloy