Technology Research Of Surface Treatment Of TiAlN Coated Carbide Tools By High Current Pulsed Electron Beam

TiAlN coated carbide tools have become the current focus of research and widely used with the rapid development of manufacturing technology. From the technical point of surface engineering, the development of TiAlN coated carbide tools has important significance. Post treatment technology of coated carbide tools will become a new way of coating technology. TiAlN coated cutting tools were treated by High-Current Pulsed Electron Beam(HCPEB) with different energy of electron beam and different pulse numbers. The influences of microstructure, mechanical properties of TiAlN coated carbide tools treated with different electron beam energy and different pulse numbers were investigated, finally the best cutting performances of coated cutting tools were obtained.The treating parameters were designed and optimized with the response surface design methods, the optimum process parameters were finally obtained. Meanwhile, the significant models of response values were analysed. Degrees of effects of various factors on response values were investigated. Then, the surface morphology and cross-section morphology of TiAlN coatings were observed by SEM, laser con focal microscope experimental equipments. The thickness, element content of the section, and phase composition of coatings were tested by SEM, EDS and XRD analytical methods and the roughness and micro-hardness of the coatings were measured. The influences of microstructure and properties of high-current pulsed electron-beam treatment of TiAlN coatings were investigated. Finally, cutting performances of untreated and treated coated tools were obtained through the turning and milling experiment.The results show that with different energy of the electron beam, the surface morphology, the element content and the performances of TiAlN coatings have been changed.The XRD patterns show that, with the increasing energy of the electron beam. The diffraction peak orientation degree of main phases of TiAlN coatings has been changed, but the coating phases are still poly crystal. The diffraction peaks of phases of TiAlN coatings migrate towards the higher angles, and have been widened. It indicates that electron-beam bombardment causes internal larger compressive stress, and grain refinement. The internal stress of coatings has driven Ti and Al’s elements in the coating into a wider distribution, to a certain extent. It is conducive to the improvement of the adhesion between substrate and coating; Stress state variation of TiAlN coatings and fine grain strengthening effect makes surface hardening. The cutting experiment results show that TiAlN coated carbide tools treated with the electron-beam energy of 32. 5J have a higher cutting life than the original coating tools in turning experiments, and TiAlN coated carbide tools treated with the electron-beam energy of 77.2 J, compared with the original coated cutting tools. Its flank wear has decreased by 60%, and its cutting performance has obviously improved.