Mechanical analysis and high temperature wear behaviour of AlCrN/DLC coated titanium alloy

Abstract

The present investigation focused on the mechanical and the tribological behaviour of PVD coated Ti-6Al-4V for elevated temperature applications. The effects of AlCrN and DLC coatings on the surface of the titanium alloys produced by arc evaporation method were studied. Nano indentation, tensile and high temperature wear tests were carried out to evaluate the hardness, strength and tribological properties of coated Ti-6Al-4V. The DLC coating on the titanium alloy exhibits a higher hardness value of 1,125 HV. The results of tensile test made clear that both AlCrN and DLC coatings can improve the plasticity of uncoated Ti-6Al-4V alloy. High temperature sliding wear characteristics of AlCrN and DLC coatings was studied under lubricated condition for elevated temperature applications. The wear tests showed that the wear rates and friction coefficients of AlCrN and DLC coatings, both increases with the increasing temperature. The wear results were compared with those of uncoated Ti-6Al-4V titanium alloys, which exhibited a lower coefficient of friction (COF) due to the change of wear mechanism to slight abrasion wear from severe delamination. The superiority of the DLC coated Ti-6Al-4V was confirmed by the final results.