Effect of solution and aging treatments on corrosion performance of laser solid formed Ti-6Al-4V alloy in a 3.5 wt. % NaCl solution

The solution and aging treatments (SAT) were adopted to improve the microstructure and the corrosion resistance ability of laser solid formed (LSFed) Ti-6Al-4 V titanium alloy. The effect of the SAT on the electrochemical properties of the LSFed Ti-6Al-4 V in a 3.5 wt. % NaCl solution was studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The microstructure changes after SAT, resulting in the transition from the columnar grains in the LSFed Ti-6Al-4 V to the basket-weave grains. After SAT, the microhardness of material is significantly reduced. The corrosion resistance of solution and aging treated (SATed) Ti-6Al-4 V is slightly better than that of the as-deposited Ti-6Al-4 V, which is manifested by the decrease of icorr value, the increase of impedance modulus and the reduction of the number of surface pits after electrochemical corrosion.