This study focuses on a comparative analysis of AlCrXN (X = Mo or V) coatings with the reference AlCrN coating via arc ion plating technique (AIP). The XRD and XPS results showed that the AlCrXN coatings were mainly composed of fcc-(Cr,Al)N solid solution phases. Both the AlCrMoN and AlCrVN coatings exhibited much higher hardness and adhesive strength than the AlCrN coating. The addition of Mo or V decreased the coefficient of friction (COF) and wear rate, which was due to the formation of lubricant oxides containing Mo or V on the coating surfaces. The cutting results showed that abrasive wear, adhesive wear, and oxidation wear were the main wear mechanisms for the coated tools at the cutting speeds of 60 m/min and 94 m/min. The addition of Mo or V dramatically improved the cutting performance of AlCrXN-coated tools by increasing the anti-wear ability due to the high hardness and the formed lubricant VO_x or MoO_x films.

AlCrN/AlCrMoN multilayer coatings with various bilayer numbers (1, 2, 4, and 6) were deposited on high speed steel (HSS) via arc ion plating technology. The effects of bilayer numbers on the microstructure, mechanical and tribological properties were investigated. XRD and TEM results showed that the solid solution (Al, Cr, Mo) N was the main phase in the AlCrN/AlCrMoN multilayer coatings. As compared with the AlCrN/AlCrMoN-1 coating, the AlCrN/AlCrMoN multilayer coatings showed the improved adhesion, hardness and tribology performance. The AlCrN/AlCrMoN-4 coating showed the highest adhesion (Lc2 = 52 N) and micro-hardness (3500 HK_0.05). The AlCrN/AlCrMoN-4 coating also exhibited the lowest friction coefficient and wear rate both at room temperature and high temperature due to the optimal structure and good overall performance.

Titanium alloys have been extensively applied due to their outstanding features, including high specific strength and corrosion resistance. However, the machining of these alloys presents challenges, leading to significant tool wear and reduced tool lifetime, ascribed to the difficult-to-machine features of Ti alloys. In the context of pursuing environmental sustainability and enhanced productivity, high-speed dry-cutting technology coupled with high-quality tool coatings are prospective. This paper comprehensively explores wear patterns and recent advancements in tool coatings for high-speed dry cutting of Ti-alloys. Key coating properties such as resistance to abrasion, adhesion, oxidation, fatigue, hot hardness, and self-adaptability are briefly introduced. Design strategies for enhancing micro-hardness, toughness, and adhesion, including nanocomposite, multilayer, and gradient architectures, are also discussed. Furthermore, the paper highlights several Boron (B) doped hard coatings as promising candidates for high-speed dry cutting against Ti-alloys, exploring the impact of B on microstructure, hardness, thermal stability, oxidation resistance, and lubrication. In summary, this work provides a systematic overview of novel B-doped tool coatings applied in high-speed dry cutting against Ti-alloys.