Investigation of microstructural changes and corrosion resistance of Ti-6Al-4V alloy after forging for biomaterials application

This study discusses the effect of the thermomechanical process on the microstructure and electrochemical behavior of a Ti6Al4V extra-low interstitial (ELI) material, which is commonly used as a load-bearing biomaterial implant. The effect of the thermomechanical process on the morphology and distribution of (α and β) phases was examined by field emission scanning electron microscopy (FESEM). The crystallographic features during the thermomechanical process were characterized thoroughly by different methods, such as the Williamson–Hall and Debye-Scherrer equation using the XRD pattern. The use of the potentiodynamic method and EIS was employed to examine the corrosion characteristics of processed alloy in Ringer's and phosphate-buffered saline (PBS) solutions at different pH values. The corrosion kinetic parameters were calculated via Tafel extrapolation analysis and AC impedance analysis. The results showed that the microstructure (percentage of alpha and beta phases, crystallite size, and microstrain) changed significantly during the forging process. Moreover, the corrosion current density for the forged sample in PBS with different pH values differed from that of the raw alloy. It exhibited a smaller range (0.1–0.3 µA cm− 2 at room temperature) with respect to the raw alloy. In addition, the thermomechanically processed alloy in the Ringer's and PBS solutions exhibited different behaviors. This research contributes to a deeper understanding of Ti6Al4V's behavior in biomedical applications by elucidating the interplay between forging, microstructure, and corrosion.