Tribocorrosion properties of Ti6Al4V after sinking ED machining with glycerin water solution and hydrocarbon dielectric fluids

Titanium alloys are usually selected for orthopedic implants because they are biomaterials that withstand biological environment with combined dynamical mechanical loads and very aggressive body fluids. However, these alloys are considered difficult to be processed by conventional machining, owing to their mechanical characteristics. Due to the ED-machining thermoelectric material removal nature, which is independent of material mechanical properties, it appears as an alternative to conventional machining processes and a technique suitable to modify surface mechanical properties. This work evaluates the ED-machining surface modification influences on the tribocorrosion properties of Ti6Al4V alloy using two different dielectric fluids, a hydrocarbon and deionized water (DI) mixed with a glycerin solution. The analysis shows that the ED machined with hydrocarbon dielectric produces a modified titanium surface with lower roughness and higher hardness due to the formation of TiC phase. The produced surface improves the tribocorrosion and wear properties of the Ti6Al4V samples. The hydrocarbon-machined samples present also a lower friction coefficient when compared with ED-machined glycerin water solution and control samples (Ti6Al4V).