Comparison of corrosion resistance for laser wire-feed vacuum additive manufactured and wrought Ti6Al4V alloy

Purpose This study aims to compare and study the differences in corrosion resistance and microstructure for a Ti6Al4V sample fabricated by wire-feed laser vacuum additive manufacturing (AM) and the wrought Ti6Al4V alloy. Design/methodology/approach An electrochemical corrosion test in 3.5 Wt.% NaCl water solution was used to study the corrosion behavior. The microstructure of each specimen was characterized by X-ray diffraction and scanning electron microscopy with electron backscatter diffraction. The passive film composition was analyzed using X-ray photoelectron spectroscopy. Findings The AM sample had inferior corrosion resistance as compared to the wrought alloy. The reason was because of the passive film formed on the wrought sample containing more TiO2, which was conducive to improving corrosion resistance. In addition, there was formation of acicular α′ phases and less β phase as well as a larger fraction of high-angle grain boundaries in the AM sample, and it led to inferior corrosion resistance compared to the wrought alloy. Originality/value To the best of the authors’ knowledge, this paper is the first time to conduct a comparative study on the difference of corrosion resistance and microstructure for the Ti6Al4V sample fabricated by wire-feed laser vacuum AM and the wrought Ti6Al4V alloy. In addition, the underlying reason was fully explained.