Effect of the cooling rate in the corrosion behavior of a hot worked Ti-6Al-4V extra-low interstitial alloy

Abstract

This work discusses the effect of the cooling rate during a forging process on the microstructure and corrosion behavior of a Ti–6Al–4V extra-low interstitial (ELI) alloy, which is commonly used as biomaterial. The samples were hot forged at two different temperatures, both of them within the dual phase field (α+β) and a constant strain rate of 4×10−3s−1 was employed during the tests. The samples were cooled in three different cooling media (water, air and clay) and the microstructure was analyzed using scanning electron microscopy (SEM). The corrosion resistance was determined by cyclic polarization tests in Ringer’s solution at 37°C. Comparison between the results obtained for forged and commercial samples allowed to establish some correlations between cooling rate, microstructure and corrosion resistance. It was found that the clay as a cooling medium is a good candidate to obtain a proper microstructure and properties for biomedical applications, eliminating the requirement of subsequent heat treatment and reducing costs.