Microstructure and corrosion behaviour of additively manufactured Ti–6Al–4V with various post-heat treatments

This paper presents the results of an experimental investigation into the effects of solution treatment, age and stress relief on the corrosion behaviour of direct metal laser sintered Ti–6Al–4V. The evidence of microstructural change and phase evolution, as affected by heat-treatment temperature, was characterised through scanning electron microscopy and X-ray diffraction. The corrosion behaviour was evaluated electrochemically in Ringer's solution, at 37°C. It was determined that the non-equilibrium α’ phase, with a small amount of β nuclei, formed in the as-printed sample. Enhancement in the resistance of the passive oxide layer on the alloy was observed after solution treatment and age, as well as after high-temperature stress relief. The structure of the passive layer of the surface showed a heat-treatment temperature dependency.