Adhesive wear of a Ti6Al4V tribopair for a fast friction contact

• Dry friction generated by a projectile impact against a couple of samples in titanium alloy in rest.
• Sliding velocities ranging from 40 m/s to 64 m/s under an apparent normal pressure of 110 MPa.
• Analyses of the material microstructure: confirmation of a decomposition into sub-layers.
• Adhesive wear rate depending on the sliding duration.

Friction tests at high sliding velocity are carried out by subjecting specimens to an apparent normal pressure of 110 MPa in the range of 40–64 m/s to reproduce severe conditions of contact between the rotating blades and the rotor in aircraft engines. Therefore, impacts of a projectile against a fixed sample are carried out for the investigation of a pair of Ti6Al4V materials. A mean coefficient of friction has been ascertained by two types of method: a tribometer device and an energetic approach. A slight sensitivity of the coefficient of friction with respect to the sliding velocity is observed. Postmortem analyses of samples reveal a decomposition of the frictional subsurface in multiple distinct layers: initial microstructure, severe plastic deformation (shear strain up to 16), phase transformation (T>980°C) and material transfer. A scenario of the adhesive wear mechanism is proposed in four steps.