Role of plastic deformation and microstructure in the micro-electrochemical behaviour of Ti-6Al-4V in sodium chloride solution

The role of alloying elements and the influence of plastic deformation on the micro-electrochemical behaviour and the pitting corrosion susceptibility of TiAl6V4 have been investigated in 10 g/L NaCl using the electrochemical microcell technique. Local electrochemical measurements have revealed that both the increase of surface roughness and the increase of dislocation density have impact on the electrochemical behaviour of TiAl6V4 after plastic deformation. It has been shown the surface roughness induced by slip band emergence is the predominant parameter responsible for the increase of the cathodic current. It has also been shown that cathodic reactions occur preferentially at surface defects (α/β interfaces, slip bands, for example). The presence of aluminium oxide in the passive film hindered cathodic reactions.