Improvement on the mechanical, tribological properties and cutting performance of AlTiN-based coatings by compositional and structural design

(Al)TiSiN multi-layered coatings are promising candidates for use in processing of difficult-to-machine materials. In this study, AlTiN and three different Si-containing multi-layered coatings were designed to fabricate by arc evaporation technology to compare the effect of composition and structure on their microstructure, mechanical and tribological properties, oxidation behavior, and cutting performance. The results indicate that (Al)TiSiN G-3 (AlTiN + AlTiSiCN + AlTiSiCN/TiSiN + TiSiN) coating exhibits high adhesion strength (similar to 87.3 N), low residual stress (similar to 3.89 GPa) and high hardness (H similar to 34.2 GPa) combined with a high elastic modulus (E similar to 403.7 GPa) and a high ratio of H3/E*(2) (similar to 0.21 GPa). (Al)TiSiN G-2 (AlTiN + AlTiSiN + AlTiSiN/TiSiN + TiSiN) and (Al)TiSiN G-3 had lower friction coefficients and wear rates than AlTiN and (Al)TiSiN G-1 (AlTiN + AlTiSiN) coatings due to a greatly reduction of abrasive wear. Oxidation resistance of the coatings was estimated in the following order: (Al)TiSiN G-1 > (Al)TiSiN G-2 > (Al)TiSiN G-3 > AlTiN. In addition, (Al)TiSiN G-3 coated tool possessed the optimal cutting performance in continuous and intermittent turning of 304 stainless steel due to the highest hardness and best toughness.

Automated summary

AlTiSiN multi-layered coatings show promise for processing difficult-to-machine materials, with AlTiSiN G-3 exhibiting the best mechanical and tribological properties. Additionally, the oxidation resistance of the coatings follows the order of AlTiSiN G-1 > AlTiSiN G-2 > AlTiSiN G-3 > AlTiN.