Influences of different temperatures on the mechanical properties and wear resistance against Ti6Al4V of Ti doped diamond-like carbon deposited on cemented carbide

Abstract

Ti doped diamond-like carbon (Ti-DLC), as an advanced tool coating material, manifests good lubricating properties and strong wear resistance. By controlling the Ti concentration, the friction coefficient and wear rate of Ti-DLC against Ti6Al4V can be controlled at a lower level. Whereas in view of the high temperature easily aroused during Ti6Al4V machining process, the composition of Ti-DLC is generally greatly affected, causing changes in the carbon structure and the Ti concentration. In the current work, Ti-DLC deposited on YG8 substrate was heat-treated at different temperatures ranging from room temperature to 400 °C. The microstructure, mechanical properties, and Ti6Al4V wear resistance of Ti-DLC were investigated by Raman spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, nano-indentation tests, and ball-on-disk friction tests. It was found that the rearrangement of the carbon matrix occurred at 300 °C. At this elevated temperature, a large amount of hydrocarbon escaped causing a significant weight loss, and the particle size on the film surface increased due to oxidation. The atomic percentage of incorporated Ti varied from 2.43 at% at room temperature to 12.43 at% at 400 °C. Abrasive wear was observed when the temperature was below 300 °C, whereas adhesive-diffusive-oxidation wear occurred when the temperature exceeded 300 °C.