Development Of(W,Ti,Ta) C/c-BN Cermet Tools And Their Cutting Performance

The low toughness and low wear resistance of cermet tool materials have limited its development.In order to promote its development,this article adopts the heterogeneous nucleation method to c-BN surface coating treatment,add it to the mixture,so that it is evenly distributed in the grains or boundaries of the ceramic phase particles,the ceramic phase and during the sintering process of the added phase particles,the residual stress caused by thermal mismatch can change the fracture mode and thereby improve the performance of the material;and the high hardness of c-BN can enhance the wear resistance of the tool;the ceramic phase is a solid solution the material can play the role of solid solution strengthening.Through the joint action of the three,（Ti,W）C-based and（W,Ti,Ta）C-based cermet tools were prepared,and their mechanical properties,microstructure and the cutting performance was studied.A coated powder（c-BN@Al₂O₃）with good dispersibility and good coating effect was prepared and added to the tool.The（Ti,W）C-based cermet tool was sintered.The strengthening mechanism of c-BN@Al₂O₃ to the tool was studied.The presence of c-BN@Al₂O₃ can inhibit the growth of（Ti,W）C particles;it can ensure that c-BN does not change its phase and exert its excellent physical properties;it will be introduced Al₂O₃material,and Al₂O₃ helps sintering,will improve the density of the material;at the same time,the presence of c-BN@Al₂O₃ will introduce a variety of toughening mechanisms such as crack deflection.Comparing the effects of c-BN and c-BN@Al₂O₃on tool materials,the effect of c-BN@Al₂O₃ is better than that of c-BN.And the tool material with 10vol.%c-BN@Al₂O₃ has the best comprehensive performance,and the flexural strength,hardness and fracture toughness can reach 1021.35±26.62 MPa,21.11±0.57 GPa and 13.25±0.42 MPa·m^1/2,respectively.The（W,Ti,Ta）C-based cermet tool material was prepared by using the multi-phase solid solution material as the ceramic phase.Compared with（Ti,W）C/Ni/Mo/Co tool material,Ta element is introduced into（W,Ti,Ta）C/Ni/Mo/Co tool material by solid solution technology,and the existence of Ta element will inhibit the growth of（W,Ti,Ta）C particles,which will cause serious lattice distortion of ceramic particles,and improve the mechanical properties of the material.At the same time,the effect of c-BN@Al₂O₃ was analyzed.The effect of adding 10vol.%c-BN@Al₂O₃ was the best.The flexural strength,hardness and fracture toughness were 1462±49 MPa,19.81±0.43GPa and 13.68±0.51 MPa·m^1/2,respectively.Finally,the cutting performance of the tool was studied,and the single-factor experimental method was used to determine the optimal cutting parameters of 40Cr,a difficult material for tool cutting.The influence of coated powder and solid solution strengthening on the cutting performance of the tool is analyzed.The results show that the existence of coated powder can improve the friction coefficient,cutting temperature,mechanical properties and service life of cutting tools.The solid solution strengthening can improve（W,Ti,Ta）C-based cermet tools.The friction coefficient can further effectively reduce the cutting performance and service life of the tool and improve the machining surface quality of the tool...