Characterization of the Microstructures and Dynamic Recrystallization Behavior of Ti-6Al-4V Titanium Alloy through Experiments and Simulations

The Ti-6Al-4V (TC4) is subjected to an isothermal compression test by the Gleeble-3800 thermal simulation testing machine, and the stress–strain curve is obtained, and the experimental data are corrected by friction. Through dynamic recrystallization (DRX) dynamic analysis and simulation, the microstructure evolution and hot compression behavior of TC4 titanium alloy under different deformation conditions are studied. The DRX behavior confirmed by microstructure observation is promoted at higher temperature and lower strain rate. In the compression process, when ε ˙ = 1 s - 1 , its softening effect increases significantly with the increase in temperature. When ε ˙ = 0.001 s - 1 and ε ˙ = 0.01 s - 1 , the softening effect is not obvious. At 1223K, the flow softening extent increases with the increase in strain rate where DRX plays a dominate role in the softening behavior. TC4 titanium alloy has obvious discontinuous yield behavior under high-temperature compression deformation conditions, and the yield value is not significantly correlated with the increase in deformation temperature. The DRX kinetics model was established to calculate the volume fraction and grain size of DRX under the investigated deformation parameters. In addition, the relationship between microstructure and deformation behavior and mechanical properties is also discussed. The excellent correlation shows that the organization and mechanical properties can be controlled by selecting suitable deformation parameters. Finally, the finite element model is combined with the kinetic equation to predict the microstructure of TC4 titanium alloy after hot compression. The result shows that the predicted value is highly consistent with the experimental value. The error of the recrystallization volume fraction does not exceed 10%. This shows that the model has excellent applicability in current research and has huge practical application potential in predicting the mechanical properties of TC4 titanium alloy after hot working.