ANALYSIS OF STRUCTURAL, MICROMECHANICAL,AND TRIBOLOGICAL PROPERTIES OF THE Ti-6AL-4V ELI ALLOYAFTER THERMAL OXIDATION

The paper presents the structural, micromechanical, and tribological characteristics of the Ti-6Al-4V ELIalloy after thermal oxidation at 575C (50 h), 625C (50 h), and 675C (20 h). The study showed that the oxidelayers obtained on the Ti-6Al-4V ELI alloy were of a good quality and had a varied microstructure dependingon the oxidation parameters. It was found that an increase in oxidation temperature was a determinant of oxideparticles’ size and continuity of the coating. The Ti-6Al-4V ELI alloy displayed better micromechanical andtribological characteristics after thermal oxidation. Surface hardness of the alloy almost doubled (by approx.4 GPa), improving tribological characteristics. Volumetric wear reduction of the investigated Ti-6Al-4V ELIalloy after oxidation ranged from 25 to 37%. The oxide film obtained at 625C (50 h) offered the mostfavorable tribological properties. It was also evidenced that the presence of oxide layers on the Ti-6Al-4V ELIalloy led to an increase in the value of the coefficient of friction.