Adhesive wear of a Ti6Al4V tribopair for a fast friction contact

Abstract

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.