A comparative study of fatigue properties of TiVN and TiNbN thin films deposited on different substrates

Transition metal nitrides, especially ternary phase films attract attention due to their high mechanical and tribological features. Besides these, fatigue properties play a very important role on the performance in service life of these types of films. TiVN and TiNbN films were deposited on M2 and H13 steel substrates by reactive magnetron sputtering system. Fatigue properties of the films were characterized via multipass scratch tests. 100, 250 and 500 cycles with bidirectional multipass scratch tests were conducted at room temperature by applying 20 N constant load. Structural properties were determined with X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. Mechanical features of the films were observed with nano hardness tests. Fatigue behaviors, deformation types, coefficient of frictions of the films and effect of different substrates were discussed comparatively. According to the results, the TiVN films showed better fatigue resistance than the TiNbN films although critical adhesion load value of the TiNbN films was higher than the TiVN films. The TiVN films generally showed ductile type cracks at the edge of the tracks and the TiNbN films showed more brittle type cracks. Additionally, the films deposited on M2 substrates exhibited better strength than those of H13 substrates.