The research objective of this award is to investigate a new concept in coatings for cutting tools that will enable dry, high-speed machining of steels and other hard-to-cut metal alloys. The approach is to design coatings that are resistant to both high-temperature oxidation and diffusion-based wear mechanisms. Current state-of-the art coatings have been promoted based primarily on their oxidation resistance. Resistance to diffusion-based wear mechanisms will be achieved using large-metal nitride compounds that have a limited solubility within the work piece to be machined. Since high-speed machining operations are subject to both oxidative and diffusion wear, multilayer coatings that are structured as alternating layers of large-metal nitrides with oxidation-resistant nitrides will be investigated. Depositing these coatings as nano-scale multilayers will also enhance the hardness and fracture resistance of the coatings. Sputter deposition and full chemical and mechanical characterization of the deposited coatings also will be carried out. Research will be conducted to evaluate the performance of these coatings during high-speed turning of steel.
The societal benefits of the research will be realized through the promotion of dry machining in place of lubricated machining. Both environmental and health concerns have been raised for machining operations that use cutting fluids. The disposal of cutting fluids has become more regulated and therefore more costly for the metal cutting industry. The success of the coatings to be examined in this study will enable a substantial reduction in the quantity of lubricant used, and in some cases complete elimination of cutting fluids during cutting.
