Biocompatible TA4 and TC4ELI with excellent mechanical properties and corrosion resistance via multiple ECAP.

Abstract

Titanium (Ti), characterized by its exceptional mechanical properties, commendable corrosion resistance and biocompatibility, has emerged as the principal functional materials for implants in biomedical and clinical applications. However, the Ti-6Al-4V (TC4ELI) alloy has cytotoxicity risks, whereas the strength of the existing industrially pure titanium TA4 is marginally inadequate and will significantly limit the scenarios of medical implants. Herein, we prepared ultrafine-grained industrial-grade pure titanium TA4 and titanium alloy TC4ELI via the equal channel angular pressing method, in which the TA4-1 sample has ultrahigh strength of 1.1 GPa and elongation of 26%. In comparison with the micrometer-crystalline Ti-based materials, it showed a 35% reduction in wear depth and more than 10% reduction in wear volume, while the difference in the corrosion potential of the simulated body fluids was not significant (only ∼20 mV). XRD, electron backscatter diffraction, and transmission electron microscope characterization confirms that their superior strengths are mainly due to grain refinement strengthening.