Tribological properties of titanium-based alloys

Titanium-based alloys (including Ti alloys and TiAl intermetallics) are very attractive for many industrial sectors owing to their unique physical, mechanical, chemical and biological properties. However, titanium and its alloys are characterised by poor tribological behaviour in terms of high and unstable friction, severe adhesive wear, low resistance to abrasion, susceptibility to fretting wear and a strong tendency to seize. This may be related to their inherent characteristics of electron configuration, crystal structure, ineffectiveness of lubrication and low thermal conductivity. The tribological behaviour of TIAl intermetallics are very similar to titanium alloys. This problem can be overcome by changing the nature of the surface, i.e. surface engineering of titanium-based alloys.