Effects of Thermo-physical properties of Ti0.41Al0.59N coating on transient and steady cutting temperature distributions in coated cemented carbide tools

Coated cutting tools have such advantages as high thermal shock resistance, excellent properties of anti-wear and anti-chemical corrosion compared with uncoated ones. However, the role and influence mechanism of coatings on thermal shock resistance and thermal barrier performance of cutting tools have not been clear. Firstly, the effects of Ti0.41Al0.59N coating on the temperature distribution within the rake face area during cutting process are quantitatively analyzed using one-dimensional transient and steady-state models proposed in this paper. The thermo-physical properties of coating and substrate with temperature are considered as varying with tool rake face temperature. The results demonstrate that lower thermal conductivity of the coating material and lower thermal diffusivity of the substrate material will generate instantaneous thermal barrier effect. The effects of Ti0.41Al0.59N coating on the thermal barrier performance and the decrease of internal temperature within the tool body are more remarkable at high temperature. Secondly, the interval time of temperature distribution within cutting tool from the transient state to the steady state is proposed and quantitatively analyzed. The interval time is mainly depended on the thermo-physical properties of the substrate material. It decreases with the increase of the tool substrate thermal conductivity, while increases with the increase of the tool substrate thermal diffusivity. Finally, the simulated experiments of heat transfer for Ti0.41Al0.59N coated cutting tools are designed to verify the numerical results. The research results provide the basis for understanding of the thermal barrier performance of Ti0.41Al0.59N coating as well as the choice of reasonable physical properties for the cutting tool materials.