Effect of Different Coatings on the Cutting Performance of Ultrafine Gradient Carbide Tools

Compared with conventional cemented carbide, ultrafine gradient cemented carbide exhibits higher hardness, toughness, and wear resistance, together with better crack resistance under high temperature and high-pressure cutting conditions. However, most studies on coated cutting tools have focused on conventional cemented carbide substrates, while studies on the compatibility between ultrafine gradient cemented carbide substrates and different coatings, as well as their cutting performance, remain limited. In this study, single-layer AlTiSiN, AlCrTiN, and multilayer CrAlTiN coatings were deposited on ultrafine gradient cemented carbide substrates using arc ion plating. Cutting experiments combined with finite element simulations were conducted to analyze tool wear behavior and temperature distribution during high-speed turning of Ti-6Al-4V alloy. The results indicate that the AlCrTiN coating shows better compatibility with the substrate than AlTiSiN and multilayer CrAlTiN coatings, exhibiting superior cutting performance. When the cutting length was below 575 m, the flank wear was approximately 0.1 mm. The error between experimental and simulation results was less than 20%, confirming the reliability of the model. In long-stroke simulations, the AlCrTiN coating effectively suppressed cutting temperature and maintained excellent wear resistance. The study reveals the differences in cutting performance among different coatings on ultrafine gradient cemented carbide substrates, providing new insights for the design of high-performance cutting tools for titanium alloy machining.