Effect of TiC addition and Co binder content in cemented carbide substrates on the microstructure and mechanical properties of the TiAlN-based composite films

Abstract

The development of cutting technologies promotes the diversification of cutting tool materials. To better guide the design and preparation of the surface films on different tools, it is necessary to explore the relationship between substrate materials and films’ properties. The TiAlN-(TiAlN/CrAlSiN)–TiAlN composite films were coated on cemented carbide substrates with different content of Co binder and TiC addition by arc ion plating. The results showed that Co binder in the cemented carbide reduced the surface energies of substrates, and the film on the cemented carbide substrate with higher Co content grew slower. (Ti,W)C phase formed in the cemented carbide substrate since WC dissolved in TiC, which was favorable for the growth of film. (Ti,W)C phase in the cemented carbide substrate improved the bonding strength of the composite film, but it reduced the hardness of the film. High Co binder content in cemented carbide substrate was disadvantageous to both the adhesion and hardness of the film. The composite films deposited on the WC-6wt%Co and WC-15 wt%TiC-6wt%Co achieved the maximum hardness and best bonding strength, respectively. The wear mechanism of the composite films on all different cemented carbide substrates was the mixture form of abrasive wear, oxidative wear, diffusion and adhesive wear.