Metastable pitting corrosion behavior of laser powder bed fusion produced Ti-6Al-4V in Hank’s solution
School of Engineering
Jiangsu Province six talent peaks project (Grant No. XCL-117), Natural Science Foundation of Jiangsu (Grant No. BK20201456, No.BK20210891 and BK20191458), Guangdong Basic and Applied Basic Research Foundation (No. 2020A1515110394), Open Foundation of Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured Materials (Grant No. 2020GXYSOF01, 2021GXYSOF03).
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.