Influence of Oxidation Temperature and Exposure Time on Surface and Tribological Properties of Ti-6Al-4V Alloy After Surface Rolling

Surface modification layers (oxide layer and oxygen diffusion region) were manufactured on Ti-6Al-4V alloy substrate by combining multi-pass surface rolling with thermal oxidation. Firstly, multi-pass surface rolling at the load of 750 N was taken to improve the microstructure and properties of material surface layer. Then thermal oxidation was conducted at the temperature of 700, 750, 800, and 850 °C for 1, 1.5, and 2 h duration, respectively. Some microscopic analysis methods (SEM, EDS and XRD) were used to characterize the surface-modified layer of the samples. The microstructure, surface morphology and microhardness dispersion region of surface-modified layers provided by the different conditions treated samples were compared. Therefore, the effects of the exposure oxidation temperature and time on the microstructure and properties of surface-modified layers were studied on the basis of multi-pass surface rolling. The friction and wear properties of the different conditions treated samples were analyzed in dry friction conditions. It could be found that the properties and wear resistance of surface-modified layer is gradually increased with the increase of oxidation temperature and time. The predominant wear mechanism is the adhesive and abrasive wear under dry friction conditions, as well as the delamination of oxide film and tribolayer.