Simulation of microstructure evolution during hot rolling of large rings of titanium alloy based on 3D-FEM

The microstructure evolution model and the rate-dependent and temperature-dependent elastic-plastic constitutive model with isotropic hardening are implemented in ABAQUS/Explicit through the subroutine VUMAT by using the elastic predictor-plastic corrector scheme combined with the implicit integration algorithm, and thus the simulation is realized with respect to microstructure evolution coupled with macro-scale mechanical and thermal behaviors. The developed subroutine is validated by comparing with experimental results in isothermal upsetting of Ti-6Al-4V cylinder. The subroutine is imbedded into the coupled thermo-mechanical 3D-FE model for hot rolling of large rings of titanium alloy, and then the characteristics and mechanism of micro-structure evolution during the process are studied. The results obtained show that along the radial direction of the deformed ring, the middle layer has smaller β grain size and β volume fraction than the exterior layer.