Kinetics and crystallography of globularization in the additively manufactured Ti-6Al-4V

This work investigates the kinetics and crystallography of globularization in the additively manufactured Ti-6Al-4V by optical microscopy, transmission electron microscopy and electron back scatter diffraction. It is found that it follows the LSW (Lifshitz-Slyozov-Wagner) model with boundary splitting when the laser-melted Ti alloy suffers from post annealing thermal treatment, where coarsening efficient 0.124. Additionally, boundary splitting does not change the orientation relationship and the orientation relationship of globular alpha grains is consistent with the precursor (widmansta center dot tten microstructures). The current study shows that the number and crystal orientation of widmansta center dot tten microstructure in prior beta grains can be tailored well, laying the foundation for manipulation of the globular grains.