Research On The Structure And Properties Of Nano Modified Ti(C, N)-based Cermets And Their Cutting Performance

As a new-style tool material instead of cemented carbide,Ti(C,N)-based cermets have been widely used in cutter manufacture owing to their outstanding physical,mechanical and wear-resistant properties.But Ti(C,N)-based cermets are less used in China at the present time.In the thesis,the cutting performance of the self-made Ti(C,N)-based cermets were studied and analysed by means of finite element method(FEM) technology and turning experiment,which can provide theoretical basis and technical support for studying the reasonable geometry of Ti(C,N)-based cermets cutting,and are of great significance to generalize Ti(C, N)-based cermets cutters in China.First,two kinds of samples were prepared by the method of traditional powder metallurgy,one is nano TiN modified TiC-based eermets cutters and another is ultra-fine Ti(C,N)-based cermets cutters.Then the composition-microstructure-property relationship of the two kinds of cermets was discussed with XRD and SEM.Results show that nano TiN modified TiC-based cermets cutters possess better mechanical properties than ultra-fine Ti(C,N)-based cermets cutters except for hardness.Next,2D and 3D machining finite element models were founded.Then the turning process of Ti(C,N)-based cermets cutters were simulated with DEFORM software.Results reveal that the best clearance angle of nano TiN modified TiC-based cermets cutters is 6°,and the best rounded cutting edge radius is 0.2mm; simultaneity,the wear-resistant property of the ultra-fine Ti(C,N)-based cermets cutters is better than nano TiN modified TiC-based cermets cutters,which is opposite to the results of latter turning experiment.Last,the turning experiment of two kinds of cutters against AISI 1045 carbon steel were carried out.Results show that when the clearance angle is 6°,the wear-resistant property of nano TiN modified TiC-based cermets cutters is the best, which proves that the machining finite element models are reasonable;at the same time,the wear mechanisms of two kinds of cutters were investigated and discussed, and the oxidative wear and diffusion wear were two principal wear mechanisms in high cutting parameters.