Design and application of B-containing hard coatings for high-speed dry cutting against Ti-alloys- A review

Abstract

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.