Microstructural evolution of a Ti–6Al–4V alloy during β-phase processing: experimental and simulative investigations

The microstructural evolution of a Ti–6Al–4V alloy during thermomechanical processing in the β-phase field was investigated using both experimental and modelling methods. The experimental results show that dynamic and/or metadynamic recrystallization occurred when the alloy was processed in the β-phase field. A model embedding fundamental metallurgical principles of dynamic recrystallization (DRX) within the cellular automaton (CA) method was able to simulate quantitatively and topographically the microstructural evolution and the flow stress–strain relationship during the thermomechanical processing. In the simulation, the dislocation density variation and the grain growth kinetics of each dynamically recrystallizing grain (R-grain) was calculated on the physical model of DRX, and the plastic flow curve was calculated directly from the dislocation density variation of the matrix grains and the R-grains. The equiaxed growth of R-grains was simulated using the CA method. The influence of strain rate and temperature on the microstructural evolution and the flow stress during dynamic recrystallization was studied, and the results compared with experiments.