Design,preparation And Cutting Performance Of CrCN-WS₂ Soft/hard Composite Coated Tool In Dry Cutting

Aiming at the problems of bad cutting friction environment and easy tool wear in dry cutting,this paper proposes to combine high hardness CrN with CrC with good friction performance to prepare CrCN hard coating,and combine it with soft coating WS2 to prepare a CrCN-WS2 soft and hard composite coating tool for dry cutting.According to the design theory and the preparation technology of CrCN-WS2 soft/hard composite coated cutting tool,a green-cutting-oriented CrCN-WS2 sof/hard composite coated cutting tool was prepared.It was applied to dry-cutting TC4 titanium alloy and CFRP.And the preparation technology of the coating and the cutting performance of the coated cutting tool were analyzed.According to the theory of residual thermal stress of coated tool,the residual thermal stress of different interlayer materials and thickness of coatings was analyzed by simulation experiment of residual thermal stress.The distribution of residual thermal stress was analyzed by equivalent residual thermal stress nephogram.The minimum residual thermal stress is at the axis of the unit,and the maximum residual thermal stress concentrates at the bond between the base and the interlayer.The optimum interlayer material and thickness were obtained.The CrCN-WS2 soft/hard composite coated cutting tools prepared in this paper are as follows:interlayer Cr-0.4μm,hard coating CrCN-1.8μm and soft coating WS2-0.8μm from the base to the top.The effects of sputtering deposition parameters(power,gas flow rate,temperature and pressure)on the thickness,hardness,crystallinity and surface morphology of CrCN hard coatings were studied.The optimum preparation parameters were obtained as follows:gas pressure is 0.8Pa,power is 300W,gas flow rate is N2:Ar=4sccm:46sccm,temperature is 200 ℃.Finally,the CrCN-WS2 soft/hard composite coated tool was successfully fabricated.Traditional uncoated tool NT,hard-coated tool CT,soft-coated WS2 tool WT and CrCN-WS2 soft/hard composite coated tool CWT were applied to dry cutting TC4 titanium alloy and CFRP at five cutting speeds,respectively.The results show that among the four cutting tools,the CrCN-WS2 soft-hard composite coated tool exhibits the best cutting performance,which can effectively reduce cutting force and heat,and the bonding of rake face is greatly improved,which is more suitable for high-speed cutting TC4 titanium alloy.