Frictional and wear performance of TiAlN/TiN coated tool against high-strength steel

Abstract

The sliding friction and high-speed turning experiments were carried out in dry conditions to reveal the anti-friction characteristics and wear mechanisms of the TiAlN/TiN coated tool against high-strength steel. The friction coefficient was collected and wear rate was calculated in the sliding tests, while the value of flank wear width was measured in the turning tests. The microstructure and composition of the worn surfaces were observed by an ESEM and an EDX, respectively. During the sliding wear process, the friction coefficient showed an upward trend with the increase of applied load, while it showed a downward trend with the increase of sliding speed. With the changes of the sliding speed and applied load, the wear volume and wear rate of the coating showed the opposite trend. The combined action of the peeling off, chipping, adhesion, mechanical scratch, element diffusion and oxidation was the dominate wear mechanisms of the TiAlN/TiN coated tool in sliding and turning process. Furthermore, the build-up layer and oxide films formed on the worn surface can prevent the direct contact of the friction pair, which played a positive role in lubrication and anti-friction.