Metastable pitting corrosion behavior of laser powder bed fusion produced Ti-6Al-4V in Hank’s solution

• Published in: Corrosion science Vol. 203; p. 110333
• Main Authors: Cui, Yu-Wei, Chen, Liang-Yu, Qin, Peng, Li, Ruifeng, Zang, Qianhao, Peng, Jinhua, Zhang, Lina, Lu, Sheng, Wang, Liqiang, Zhang, Lai-Chang
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 15.07.2022; Elsevier BV
• Subjects: Cations; Corrosion behavior; Laser powder bed fusion; Metastable pitting corrosion; Nucleation; Passive film; Pitting (corrosion); Powder beds; Titanium alloy; Titanium base alloys; Vacancies; Titanium alloy; Laser powder bed fusion; Metastable pitting corrosion; Passive film; Corrosion behavior
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2022.110333

The metastable pitting corrosion behavior of laser powder bed fusion (LPBF) produced Ti-6Al-4V is still unclear. Therefore, this work investigated the metastable pitting corrosion of LPBF-produced Ti-6Al-4V in Hank’s solution by electrochemical methods. The LPBF-produced sample (dominant by α′ phase in the microstructure) shows a higher frequency of pit nucleation than the annealed counterpart (composed by α + β dual phase). The passive films formed on the LPBF-produced sample exhibit a higher flux of oxygen vacancies, resulting in the absorption of more aggressive ions (e.g., Cl-) thereby producing more cation vacancies. The condensation of excessive cation vacancies contributes to the pit nucleation. [Display omitted] •Laser powder bed fusion (LPBF) produced Ti–6Al–4 V alloy was used as the sample.•Corrosion behavior of the LPBF-produced sample was investigated in Hank’s solution.•The LPBF-produced Ti-6Al-4 V shows frequent metastable pitting corrosion.•The flux of oxygen vacancy is large in the passive film of LPBF-produced Ti-6Al-4 V.•Redundant vacancies assemble and condense into a void at metal/film interface.