Correlation of Tribological Properties of Titanium Alloys with their Microstructures

Abstract

In general titanium alloys are associated with biomedical applications due to their unique properties such as: high biocompatibility, high strength to density ratio. They have been commonly used as a prosthetic material. However the microstructural development by heat treatment, directly correlated with the changes in mechanical properties of the material, allows us to consider these alloys as components of machines. One of the main properties of machine components are tribological properties. Knowledge of tribological properties of the machine elements allow us to determine the parts' viability and improve the functionality of the entire engineering system. Titanium alloys are characterized by the low wear resistance caused by chemical reactivity and easy formation of adhesion joints. Intensive adhesive wear of this material is associated with the strong degradation of the material surface. To determine the influence of microstructure on the tribological properties of titanium alloys, dry sliding wear test was performed. The materials for the investigations were five titanium alloys. The tribological test was performed with a load of 100 N for 2000 s on a 500 m distance. The microstructural observations were performed by light microscopy, in addition the wear mechanism was also investigated and for each sample the mechanism of wear was defined. For this type of tribological test a small proportion of adhesive wear was observed. The main mechanisms of wear were microgridding and microcutting. The increase of material hardness does not seem to impact on the increase of average friction coefficient of the samples. Increase of friction coefficient corresponds to the decrease of mass loss for the titanium alloys.