On the development of a dual-layered diamond-coated tool for the effective machining of titanium Ti-6Al-4V alloy

• Published in: Journal of physics. D, Applied physics Applied physics, 2017-01, Vol.50 (1), p.15302
• Main Authors: Srinivasan, Balaji, Ramachandra Rao, M S, Rao, Balkrishna C
• Format: Article
• Language: English
• Subjects: aerospace; diamond coating; dual layered; machining; titanium Ti-6Al-4V
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/1361-6463/50/1/015302

This work is focused on the development of a dual-layered diamond-coated tungsten carbide tool for machining titanium Ti-6Al-4V alloy. A hot-filament chemical vapor deposition technique was used to synthesize diamond films on tungsten carbide tools. A boron-doped diamond interlayer was added to a microcrystalline diamond layer in an attempt to improve the interface adhesion strength. The dual-layered diamond-coated tool was employed in machining at cutting speeds in the range of 70 to 150 m min−1 with a lower feed and a lower depth of cut of 0.5 mm rev−1 and 0.5 mm, respectively, to operate in the transition from adhesion- to diffusion-tool-wear and thereby arrive at suitable conditions for enhancing tool life. The proposed tool was then compared, on the basis of performance under real-time cutting conditions, with commercially available microcrystalline diamond, nanocrystalline diamond, titanium nitride and uncoated tungsten carbide tools. The life and surface finish of the proposed dual-layered tool and uncoated tungsten carbide were also investigated in interrupted cutting such as milling. The results of this study show a significant improvement in tool life and finish of Ti-6Al-4V parts machined with the dual-layered diamond-coated tool when compared with its uncoated counterpart. These results pave the way for the use of a low-cost tool, with respect to, polycrystalline diamond for enhancing both tool life and machining productivity in critical sectors fabricating parts out of titanium Ti-6Al-4V alloy. The application of this coating technology can also be extended to the machining of non-ferrous alloys owing to its better adhesion strength.