Study On Strengthening And Toughening Of Ti(C,N)-based Cermets

As one of the important components of cutting tool,it directly affect s the quality and efficiency of cutting.As the new tools materials,Ti（C,N）-based ceramics have high red hardness,wear resistance and excellent chemical stability.However,the strength and toughness of Ti（C,N）-based cermet is still insufficient and it is easy to break in the cutting process.In this paper,Ti（C,N）-based cermet materials were prepared by powder metallurgy,the effects of raw material composition on the microstructure,hardness,strength,toughness and other properties of cermet were discussed in detail.In this paper,the effects of Ru on the microstructure,mechanical properties,cutting properties and corrosion resistance of Ti（C,N）-based cermets are systematically studied.The experimental results show that:Ru can be diffused into the binder phase of cermet to refine Ti（C,N）grains;the binder phase of cermet was strengthened by solution strengthening mechanism,which improved the mechanical properties of the matrix.Ti（C,N）-based ceramics with 1.0 wt%Ru have excellent mechanical properties:the hardness is 92.6 HRA,the transverse fracture strength is2806 MPa and the fracture toughness is 9.11 MPa m^1/2.In addition,Ru in the binder phase can improve the wear resistance of cermet and significantly improve the service life of tools.When 0.5 wt%Ru is added to cermet,it can inhibit the dissolution process of binder phase in hydrochlori c acid solution and improve the corrosion resistance of cermet.In this paper,the influences of ultrafine Ti（C,N）additions on the microstructure,mechanical properties,wear resistance and corrosion resistance of Ti（C,N）-based cermets are investigated systematically.The experimental results show that:the proper ultrafine Ti（C,N）additions in Ti（C,N）cermets generate an inhomogeneous microstructure with a hybrid distribution of micron and ultrafine grains and increase the hardness of cermets obviousl y.In addition,adding a proper amount of ultrafine Ti（C,N）particles into Ti（C,N）cermets can inhibit the crack growth and improve the strength and toughness of cermets.In cermets,the combination of ultrafine and micro Ti（C,N）grains can make the matrix obtain excellent wear resistance.The addition of ultrafine Ti（C,N）particles will increase the grain boundary,which may reduce the corrosion resistance of cermet in acid solution.In this paper,the effects of carbon fiber on the microstructure,mec hanical properties,wear resistance and corrosion resistance of Ti（C,N）-based cermets were studied.The experimental results show that:adding a proper amount of carbon fiber to Ti（C,N）-based cermets can make cermets form fiber-reinforced microstructure.The hardness and toughness of cermets are enhanced by a series of strengthening measures.However,adding excess carbon fiber will hinder the diffusion of various elements and material migration in the process of liquid phase sintering of cermet,increase the micropores and defects in the matrix,and reduce the mechanical properties of cermet.In addition,adding carbon fiber to Ti（C,N）cermet can improve the wear resistance and corrosion resistance of the material.