Coarse columnar β grains result in anisotropic mechanical properties in Ti alloys deposited by additive manufacturing. This study reports that Ti–6Al–4V alloy fabricated by coaxial electron beam wire feeding additive manufacturing presents a weak anisotropy, high strength and ductility. The superior tensile property arises from a microstructure with fine equiaxed β grains (EGβ), discontinuous grain boundary α phase and short intragranular α lamellae. A large region of fine EGβ arises from a special combination of the temperature gradient and solidification rate, and attractive α morphology is caused by solid phase transformations during interpass thermal cycling and post heat treatments.
- Directed energy deposition
- Equiaxed β grain
- Tensile properties
- Ti–6Al–4V alloy
- Wire feeding additive manufacturing