Numerical analysis of phase transformation characteristics in hot forging and subsequent air cooling processes of Ti-6Al-4V turbine blade

This work is motivated by the fact that for titanium alloys, the phase transformation characteristics of forged parts decided by hot forging operation have a strong genetic effect on the microstructures of cooled parts after subsequent air cooling process, further influencing the mechanical properties of final parts. In this paper, a 3D FE approach embedded with phase transformation models is developed for the numerical prediction of phase transformation characteristics in the hot forging and subsequent air cooling processes of Ti-6Al-4V turbine blade. Then, the temperature and phase distributions of forged and cooled blades are analyzed in detail. Further, two indexes, including average and standard deviation values, are employed to quantitatively reveal the general level and uniformity evolutions of temperature and different phases during the blade hot forging and subsequent air cooling processes. Finally, the validation of simulated results is verified by experiments. The results show that the phase distributions of forged and cooled blades are uneven, and the volume fraction of α phase is mainly influenced by the hot forging process.