Alloying-Driven Mechanical Enhancement in TiAlN Coatings with Mo and Mo/W

TiAlN-based coatings are widely used in demanding machining applications; however, further improvement of their mechanical and tribological performance is required under increasingly severe operating conditions. In this study, the effect of progressive refractory metal alloying on the performance of TiAlN-based coatings was investigated by comparing TiAlN, TiAlMoN, and TiAlMoWN coatings deposited by reactive magnetron sputtering. The incorporation of Mo and Mo/W induced compositional and microstructural modifications, resulting in fine surface and cross-sectional structure features. Alloying progressively improved the mechanical response, with increased hardness and higher H/Er and H3/Er2 ratios, suggesting improved elastic strain tolerance and resistance to plastic deformation. The tribological performance was strongly influenced by alloying, with Mo addition reducing the wear rate by approximately 50% compared with the TiAlN reference coating, while subsequent W incorporation maintained the improved wear resistance and further increased hardness and deformation-resistance indicators. These results demonstrate that the performance of multicomponent TiAlN-based coatings must be assessed through their mechanical response and sliding durability rather than hardness alone. The findings provide insight into the design of refractory metal-alloyed nitride coatings for high-performance machining applications.