Surface Modification of Cemented Carbide Substrates with AlTiXN/AlTiN（X = Cr,Si） Multilayered Coatings

The surfaces of cemented carbide substrate and face-milling tool were modified with the AlTi (X) N/AlTiN (X = Cr, Si) multilayered coatings synthesized by arc ion plating. The interfacial adhesion and surface tribological behavior of the multilayered coatings were characterized with scanning electron microscopy, X-ray diffraction, energy dispersive spectroscopy and conventional mechanical probes. The results show that the smooth compact multilayered coatings with strong interfacial adhesion significantly improved the surface hardness and wear-resistance to varying degrees. For example, the interfacial adhesion of the AlTiN, AlTiCrN/AlTiN and AlTiSiN/AlTiN coatings were 47, 49. 79 and 53. 76 N, respectively. The increased milling lifetime of the surface modified tools was listed in an ascending order: AlTiN < AlTiCrN/AlTiN < AlTiSiN/AlTiN. The adhesion-wear, abrasive-wear and oxidationwearpossibly accounted for the wear mechanisms of the multilayered coatings. We suggest that the AlTi (X) N/AlTiN (X = Cr, Si) coatings be of some technological interest in machining of titanium alloys.