Corrosion behavior of dual-phase Ti–6Al–4V alloys: A discussion on the impact of Fe content

Abstract

Fe is a promising alloying element for the development of high strength Ti alloys. However, the distribution and phase structure of Fe in Ti alloys would have an important effect on their corrosion resistance. Therefore, the effect of Fe content on the corrosion behavior of dual-phase Ti–6Al–4V alloys was studied using a galvanic coupling technique together with the electron probe X–ray microanalysis (EPMA) and Kelvin probe force microscope (KPFM). The results indicate that the Fe is enriched in the β phases, resulting in an increase in Volta potential difference between the β and α phases. Ti–6Al–4V alloy with high Fe content (TC4-H) shows worse crevice corrosion resistance than Ti–6Al–4V alloy with low Fe content (TC4-L), which can be attributed to the worse compactness and passivation ability of the passive film on TC4-H due to Fe doping.