Effect of modulation period on microstructure and mechanical properties of (AlSiTiVNbCr)N/(AlSiTiVNbCr)CN nano-multilayer films

(AlSiTiVNbCr)N/(AlSiTiVNbCr)CN nano-multilayer films were prepared by reactive magnetron sputtering under different modulation periods. The effects of modulation period on the microstructural evolution and mechanical properties of the films were studied. The microstructure and mechanical properties of the films were characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), nano-indentation instrument and scratch test. The results show that the modulation periods of (AlSiTiVNbCr)N/(AlSiTiVNbCr)CN nano-multilayer films are 133.00 nm, 57.80 nm, 23.12 nm and 7.71 nm, respectively. All films exhibit a single face-centered-cubic (FCC) structure. With the decrease of modulation period, the intensity of (220) diffraction peak increases significantly, and the intensity of (200) diffraction peak disappear, indicating that the preferred orientation of the films is (220). When the modulation period is 7.71 nm, the film exhibit an outstanding hardness of 47.64 ± 5 GPa, elastic modulus of 318.36 ± 26 GPa, and adhesion strength of 78 N with the highest H/E and H2/E. The strengthening effect is mainly attributed to the super-hard effect, which caused by the decrease of grain size and the increase of interfaces. Based on the outstanding properties of nano-multilayer films, (AlSiTiVNbCr)N/(AlSiTiVNbCr)CN films present a potential application prospect on cutting tools.