The effect of microstructure on the corrosion behavior of Ti-6Al-4V titanium alloy was
investigated. Solution annealing at 1066 oC for 1 h followed by cooling at different rate was
applied. The microstructure as well as the chemical composition changes after heat treatment
was analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy
(EDS). Dual phase (a+ß) microstructure was obtained for the solution annealed alloy either
cooled in air or in furnace, while martensite was obtained if it was water-quenched. The stability
of passive film formed in air or in 1 M HCl + 0.5 M H2SO4 mixed solution was investigated by
conducting potential decay measurement and Auger electron spectroscopy (AES). At open
circuit potential, selective dissolution of vanadium-depleted a phase in 1 M HCl + 0.5 M H2SO4
mixed solution was found.
Keywords: Ti-6Al-4V alloy, selective dissolution, potential decay, passivity