The Corrosion Performance of Ti6Al4V Alloy after Dry Heat Sterilization with Respect to the Initial Microstructure

Beta-annealing heat treatments were performed on Ti6Al4V samples at 1050 and 1100 °C for 15 and 60 min and at two different cooling rates. The corrosion behavior, before and after dry heat sterilization, was evaluated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). Results show that the increase in annealing time from 15 to 60 min increases the α-lamella thickness from 1.3 to 2.1 µm. The PDP and EIS results showed that the furnace cooled beta-annealed sample at 1050 °C for 15 min, so-called 1050-15-F, with the finest microstructural features, had the lowest corrosion rate equal to 0.8 × 10⁻² mm/year. The reduction of samples' corrosion rate after sterilization was highly dependent on the initial microstructure before sterilization. Compared to other samples, 1050-15-F sample with the highest naturally oxide layer thickness before sterilization showed the lowest %reduction of ≈ 52% in its corrosion rate.