Microstructural characterization and comparison of Ti-6Al-4V manufactured with different additive manufacturing processes

In this work, the microstructures of Ti-6Al-4V manufactured by different additive manufacturing (AM) processes have been characterized and compared. The microstructural features that were characterized are the alpha lath thickness, grain boundary alpha (GB-alpha) thickness, prior beta grain size and alpha colony size. In addition, the micro-hardnesses were also measured and compared. The microstructure of shaped metal deposited (SMD) Ti-6Al-4V material showed the smallest variations in alpha lath size, whereas the material manufactured with laser metal wire deposition-0 (LMwD-0) showed the largest variation. The prior beta grain size was found to be smaller in material manufactured with powder bed fusion (PBF) as compared with corresponding material manufactured with the directed energy deposition (DED) processes. Parallel bands were only observed in materials manufactured with DED processes while being non-present in material manufactured with PBF processes.