The dynamic recrystallization behavior of the Ti-5.5Mo-7.2Al-4.5Zr-2.6Sn-2.1Cr titanium alloy during hot rolling based on macro-meso multiscale crystal plasticity finite element approach

The understanding of dynamic recrystallization under complex thermo-mechanical coupling is still a technical challenge. Therefore, in this work, combining the Johnson-Mehl-Avrami-Kolmogorov recrystallization grain model, a macro-meso multiscale crystal plasticity finite element approach was innovatively proposed. The isothermal hot compression test was performed to obtain the true stress-strain curves of Ti-5.5Mo-7.2Al-4.5Zr-2.6Sn-2.1Cr titanium alloy (strain rates: 0.001 s⁻¹, 0.01 s⁻¹, 0.1 s⁻¹, 1 s⁻¹, and 10 s⁻¹; temperatures: 650 ℃, 700 ℃, 750 ℃, 800 ℃, and 850 ℃). Afterward, corresponding fitted parameters can be used to update the volume fraction and size of recrystallized grains of each sub-step. The macro simulation results showed that the surface layer had prominent strain partitioning and lower equivalent stress after hot rolling (thickness reduction: 60 %). For the region of interest, the calculated volume fraction and equivalent circle diameter of recrystallized grains were 2.45% and ∼1 µm, respectively, which were in good agreement with the experimental results.