Optimization of tribological parameters to enhance wear and friction properties of Ti6Al4V alloy using Taguchi method

Abstract

The present study is an endeavor to investigate the wear and friction behavior of Ti6Al4V against alumina (Al2O3) using a pin-on-disc tribometer at room temperature. The tests were performed for a given range of loads (10–90 N) and sliding velocities (0.5–4 m/s) for a sliding distance of 3000 m. The wear rate increased continuously with load and showed transition behavior with respect to the sliding velocity. Minimum friction was observed at the intermediate sliding velocities. Using the Taguchi tool, it was found that the load influenced the wear rate more significantly than the sliding velocity and the behavior was the opposite for the coefficient of friction. A wear model was predicted using regression, and subsequent confirmatory tests were carried out to validate the same. The ex-situ characterization of both worn-out surfaces and wear debris was conducted using Scanning Electron Microscope (SEM) along with the Energy Dispersion Spectroscopy (EDS) to study the surface morphology and level of oxidation, respectively. The wear mechanism was found to be a combination of adhesion, abrasion, oxidation, and delamination wear. The distinct lower wear rates at higher loads and velocities were attributed to the formation of Ti8O15 revealed by the X-ray diffraction (XRD) study.