Oxygen Diffusion Layer on Ti–6Al–4V Alloy: Scratch and Dry Wear Resistance

Abstract

Oxygen diffusion layer (ODL) was produced on Ti-6Al-4V by thermal oxidation at a temperature of 850 °C for 3 and 6 h. Hardness of the samples was measured using a nano-indentation tester.Micro-scratch tests were performed under progressive and constant normal loads of 0 50 N. Dry wear behavior of the samples was studied using a ball-on-disk tribometer. The wear tests were carried out under various normal loads of 7.5, 15 and 30 N for sliding distances of 50, 100, 200 and 300 m using alumina balls as the counterface. The wear and scratch tracks were examined by scanning electron microscope and surface profilometer. The ODL samples showed higher hardness and lower plastic deformation as compared with Ti-6Al-4V. The brittle behavior of the ODL samples caused the formation of cracks and the development of large acoustic signals during scratching under normal loads of 40 and 50 N. The results also showed a higher scratch and wear resistance of the ODL samples compared with Ti-6Al-4V. However, the oxygen diffusion layer formed after 3 h of oxidation showed a sharp increase in the wear rate of the alloy under a normal load of 30 N and a sliding distance of 100 m.

Influence of Interstitial Oxygen on the Tribology of Ti6Al4V

“…It appears that adhesive wear can be avoided and wear volume reduced by more than two orders of magnitude. Similarly, thermal oxidation can produce an oxygen-rich diffusion layer at the surface and similar reductions in wear are reported [25,26]. It should be noted that besides a nm-thin passivation layer, no thick titanium oxide layer was reported for these experiments.…”

Effect of ultrasonic surface deep rolling combined with oxygen boost diffusion treatment on fatigue properties of pure titanium

“…It has been confirmed that the ODZ can improve the surface hardness and wear resistance [7][8][9] . However, the effect of USDR-OBD treatment on the fatigue properties of titanium is still unclear.…”

“…Various surface modification methods have been applied to enhance the surface properties and fatigue resistance of titanium and its alloys 2 . Among the existing methods, surface thermo-chemical methods, including nitriding 3 , carburizing 4 , boriding 5 , and oxidizing 6,7 , have been developed for improving the surface hardness and wear resistance. To get better surface properties, a technique for obtaining higher surface hardness named oxygen boost diffusion (OBD) treatment has been proposed by Dong et al 8 .…”

Improving the Adhesion of a Hard Oxide Layer on Ti6Al4V by a Three‐Step Thermal Oxidation Process

“…Different thermal oxidation processes have been deployed to optimize the tribological properties. The simplest concept is a singlestep air oxidation, often conducted in a temperature range from 600 to 850 C. [12,14,16,[26][27][28][29][30][31][32][33] Oxygen diffusion zones, and thus zones of a gradual hardness decrease, obtained by this process have depths generally much less than 100 μm. [12,14,[26][27][28] Reaching for thicker oxygen diffusion zones by single-step air oxidation is difficult because increasing the process temperature or the oxidation duration results in porous and less adherent oxide layers.…”