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

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 alpha ' phase in the microstructure) shows a higher frequency of pit nucleation than the annealed counterpart (composed by alpha + beta 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.

Automated summary

This study investigated the metastable pitting corrosion behavior of LPBF-produced Ti-6Al-4V in Hank's solution using electrochemical methods. The LPBF-produced sample showed a higher frequency of pit nucleation compared to the annealed counterpart, mainly due to the passive films formed on the LPBF-produced sample having a higher flux of oxygen vacancies, absorbing more aggressive ions and producing more cation vacancies.