Mechanical properties of (Ti, Al)N monolayer and TiN/(Ti, Al)N multilayer coatings

Magnetron sputtered (Ti, Al)N monolayer and TiN/(Ti, Al)N multilayer coatings were deposited on cemented carbide substrates. Microstructure and mechanical properties of two coatings have been characterized by using electron probe microanalysis (EPMA), scanning electron spectroscopy (SEM), typical secondary ion mass spectroanalyzer (SIMS), nanoindentation, Rockwell A indentation test and cutting tests. Experimental results show that a (Ti, Al)N monolayer coating has dense columnar structures, and (Ti, Al)N grains of TiN/(Ti, Al)N multilayer are still fine columnar crystals though TiN layer periodically interrupt the growth of columnar in (Ti, Al)N. The crystal structure of (Ti, Al)N is face-centered cubic (fcc) structure, when the AlN content is 50 mol%. It is found that the TiN/(Ti, Al)N multilayer coating exhibits higher hardness, lower brittleness and excellent cutting performance, compared with (Ti, Al)N monolayer coating.