Analysis on the Wear Performances of Cemented Carbide Tools Containing Ti in the Coatings When Machining Ti-6Al-4V Alloys

Because of the high affinity of the same element Ti, cemented carbide tools containing Ti seem to be non-optimal in machining titanium alloys. However, in practice, cemented carbide tools containing Ti are still widely used in machining titanium alloys. Cutting experiments were conducted in order to systematically explain the contradictions between the practice and theory. The diffusion process between titanium alloys and the cemented carbide tools was analyzed by auger electron spectroscopy detecting the cutting regions. It was also analyzed by Ti/Co diffusion behavior simulated by molecular thermodynamics. The experimental results and the simulation results showed that the mutual diffusion of Ti/Co atoms was the major reason for the diffusion wear. The dissolution-diffusion wear was one of the main wear mechanisms for the cemented carbide tools containing Ti in the coatings. Moreover, four types of cemented carbide tools and two other types of cermet tools were used to machine the Ti-6Al-4V alloys at different cutting speeds to further verify the high affinity of cutting tools containing Ti in the substrate/coating. The verification experiments results showed that the cemented carbide tools containing Ti generally cannot be used for machining titanium alloys, but could show less affinity in the cutting regions with reasonable cutting conditions.