An investigation of unbalanced-magnetron sputtered TiAlN films on SKH51 high-speed steel

A thin coating of TiAlN was deposited on SKH51 high-speed steel using an unbalanced-magnetron sputtering process. The chemical composition, microstructure and mechanical properties of deposited TiAlN films were investigated. The Ti/Al ratio of TiAlN films can be successfully predicted from the sputtering parameters, involving the applied target currents, the yielding of targets impinged by Ar ions and the target configurations. When Ti atoms are partially replaced by Al atoms during the deposition, TiAlN films are identified as a δ-TiN structure and have the preferred texture of the (200) plane. The more internal stress occurring within the deposited TiAlN films is suggested to result in adhesion of TiAlN films inferior to that of TiN films under the same sputtering condition. TiAlN film with a 50% Ti fraction exhibits an excellent cutting performance due to the slight adhesion of SKS-95 steel fragments during the cutting process.