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

Abstract

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 α grains is consistent with the precursor (widmanstätten microstructures). The current study shows that the number and crystal orientation of widmanstätten microstructure in prior β grains can be tailored well, laying the foundation for manipulation of the globular grains.

Keywords

• Laser processing
• Ti alloys
• Globularization
• Kinetics
• Crystal structure