Influence of a large pulsed electron beam (LPEB) on the corrosion resistance of Ti-6Al-7Nb alloys

Abstract

Pulsed electron-beam irradiation was used as a finishing process for Ti-6Al-7Nb titanium alloy to increase the corrosion resistance and surface hardness. The corrosion characteristics were investigated using potentiodynamic polarization and electrochemical impedance spectroscopy to obtain Nyquist plots and log(f)-|. Z| plots. The surface hardness was examined using nano-indentation with a Berkovich tip. The corrosion resistance of the irradiated surface increased, exhibiting a nobler corrosion potential, a higher polarization resistance, and a lower corrosion current density than the untreated surface. The variation in the contact angle and formation of a re-solidified passivation layer indicate a stable surface. The surface hardness increased significantly following irradiation, which was attributed to an increase in the density of dislocations and a decrease in the fraction of the pre-dominant slip plane.