Effect of Al content on microstructure and mechanical properties of Ti–Al–Si–N nanocomposite coatings

Ti–Al–Si–N coatings, which consist of 6 at% Si and different Ti/Al atomic ratios deposited onto cemented carbide using cathodic arc evaporation, form nanocomposite structure of nanocrystalline (nc)-TiAlN encapsulated in an amorphous (a)-Si3N4 tissue phase. The improved mechanical properties for hardness and cutting performance were obtained with increasing Al content that accompanies the distribution variation of a-Si3N4 tissue phase and decreased TiAlN grain size and improved hardness.