Corrosion behavior of additive manufactured Ti-6Al-4V in sulfamic acid cleaning solution

In the current work, the corrosion behaviors of Ti-6Al-4V alloys manufactured using spark plasma sintering (SPS), selective laser melting (SLM) and electron beam melting (EBM) techniques are comparably investigated using aircraft deicer (10% sulfamic acid cleaning solution, 10-SACS). The corrosion resistance of different Ti-6Al-4V samples is mainly characterized using electrochemical measurements and immersion tests. The traditional SPS Ti-6Al-4V alloy has a stronger corrosion resistance compared to the SLM Ti-6Al-4V alloy, and the one manufactured using the EBM technique is the most vulnerable among all samples tested. Based on the X-ray diffraction (XRD) measurements, the β-phase constitution fraction of SPS Ti-6Al-4V is 11.8%, while those of SLM and EBM Ti-6Al-4V alloys are 5.3% and 2.6%, respectively. The corrosion resistance of Ti-6Al-4V alloys against 10-SACS is found to be positively correlated to the β phase composition. In addition, a high density of coarse grain boundaries is also partially beneficial in improving the corrosion resistance in the SPS sample. This work paves a way for the practical application of additive manufactured Ti-6Al-4V alloys to be used in harsh environments.