Oxide dependent wear mechanisms of titanium against a steel counterface: Influence of SMAT nanostructured surface

The analysis of the tribological behavior of a steel ball on pure titanium has been carried out under alternative motion on both, a coarse grained Ti surface and its nanostructured derivative obtained by surface mechanical attrition treatment (SMAT). Along the duration of the tribology test, variations in friction behavior were interpreted as a three stages sequence of different wear mechanisms that were controlled by the successive formation of Ti-rich and Fe-rich oxides. Surface nanostructures appeared to change the oxide formation kinetics and delay the formation of a protective Fe-rich third body oxide layer on Ti. The results indicate that apparently contradicting literature results can be explained by taking into account the contamination induced during the SMAT process.