Microstructure, mechanical properties and high-speed dry-cutting performance of AlCrSiCN composite coatings
Wei Fang, Junkai Chen, Qi Zhou, Haipeng Xue, Fei Cai, Leiqi Fang, Shihong Zhang
Abstract
AlCrSiCN specimens with different carbon contents were fabricated by cathodic vacuum arc technique, and the microstructures, mechanical property, tribological and high-speed dry-cutting performance were investigated. The results show that the structural transformation from dense and fine nanocomposite to coarse columnar structures was found for the AlCrSiCN coatings when increasing the C content. The excess carbon was presented in the form of nanocrystalline graphite and/or amorphous carbon. Addition of C also reduces the surface roughness and the micro-hardness. The adhesive strengths of AlCrSiCN coatings (such as C10 and C20 coatings) with a low C content were enhanced, whereas it decreased to a value of Lc2 of 17.7 N when the C content increased to 5.58 at. % for C30 coating. Tribological experiments showed that C atoms reduced the coefficient of friction due to the lubricating effect of nanocrystalline graphite and/or amorphous carbon. The high-speed dry-cutting results also showed that AlCrSiCN-coated tools performed better than those with an AlCrSiN coating, and the coatings (C10) with a lower C content possessed the greatest wear resistance.