Electromagnetic Sensing of the Corrosion at Different Microstructural Phases in a Medical Ti-6Al-4V ELI Alloy

Titanium alloys have become increasingly important for biomedical materials due to their high specific strength, good corrosion resistance, and excellent biocompatibility. In this research work, different heat treatments were performed for obtaining equiaxed and Widmanstätten microstructures of Ti-Al-4V extra low interstitials (ELI) alloy. To promote nucleation of
$\alpha _{2}$
precipitates (Ti
₃
Al), an aging process was carried out at 515 °C and 575 °C for 2, 288, and 576 h. The corrosion behavior was analyzed by double-cycle potentiodynamic corrosion tests. Hank’s balanced salt solution (HBSS) was used as the electrolyte, and the tests were maintained at 37 °C. This study uses the eddy current (EC) nondestructive evaluation technique, based on the principle of electromagnetic induction, in an effort to monitor corrosion damage in the medical Ti-6Al-4V alloy. The experimental results show significative electrical conductivity variations in EC data of different Ti-6Al-4V ELI alloy microstructures mainly on equiaxed and Widmanstätten conditions before and after corrosion performance.