涂层刀具表面强化技术研究现状及发展趋势OA

The manufacture of high-performance tools is facing challenges by the emergence of higher strength materials and more efficient,precise and low-damage machining process.Coated tools could suffer from the degradation of mechanical properties,interfacial failure and coating spalling under the severe thermo-mechanical coupling conditions,which could lead to the acceleration of tool wear significantly.Surface strengthening treatment of the coated tool could achieve the effect of regulating interfacial adhesion properties and enhancing the mechanical performance of tool material.Thus,it is of great significance to attain the strengthening and toughening of coated tool.Firstly,the process principles and recent advances in three surface strengthening technologies for coated tools of the phase transformation strengthening,strain strengthening and high-energy surface layer strengthening were reviewed.Then,the effect mechanisms of specific processes such as the heat treatment and cryogenic treatment(phase transformation strengthening),the shot peening treatment(strain strengthening),the pulsed magnetic field treatment and pulsed electron beam treatment as well as the laser treatment(high-energy surface layer strengthening)were discussed in detail.The surface mechanical properties,interfacial adhesion properties and cutting performance of coated tools under the strengthening treatments were evaluated.It was demonstrated that the optimization of process parameters played a critical role in improving the hardness and interfacial adhesion properties of coated tools.The coating/substrate interfacial adhesion properties could be enhanced by the regulation of internal stress state and the refinement of microstructure of coated tools during the heat treatment and cryogenic treatment.The hardness of coated tools could be improved by the elastic-plastic deformation and strain hardening effect during the shot peening treatment.The defect density within the coating was reduced and the residual stress distribution of coated tools could be modified during the pulsed magnetic field treatment.This could increase the resistance of coating spalling and enhance the cutting performance of coated tools.The elemental diffusion effect at the coating/substrate interface was promoted during the pulsed electron beam treatment.This could increase the thickness of the transition layer at the coating/substrate interface,and improve the bonding strength between the coating and substrate.The laser strengthening treatment could accurately locate the modified position of coated tools and reduce the surface roughness of the coating.The performance enhancement mechanisms of the coating/substrate interface after strengthening treatment could be due to the comprehensive strengthening effect of the dislocation tangle,twinning and grain refinement.The gradient organizational structure generated at the coating/substrate interface after strengthening treatment could improve the cutting performance of coated tools.In addition,it could be noted that the optimization of different process parameters had a significant improvement on the performance strengthening of the coated tool.However,there was a critical value of the different process parameters.Once the critical values were exceeded,continuing to increase,the parameter values would reduce the service performance of the coated tools.Finally,the critical challenges of the performance strengthening technology of coated tools were summarized.The future research direction and the development strategy of the high-performance coated tool strengthening technology were proposed.