The Preliminary Research Of Ti (c, N) Based Cermets Without Tungsten And Cobalt

In this study, two different mass ratio of Ti(C,N) /TiC based cermets without tungsten and cobalt were made by powder metallurgieal method. By using cobalt magnetic meter, coercive force meter, X-ray diffraction, back scattered electrons and spectra, the materials were characterized and analyzed from the microstructure,physics,mechanical,microstructure and micro-area composition. Effect of the different contents of NbC and microcontent boron etc on the macroscopic mechanical properties of cermets were explained by the differences of microstructure. Finally, the milling performances of blades which were made in this experiment and YNG151 trademark were investigated, wear mechanism and cutting life of cermet tools were compared in the high cutting speed.Through studying microstructure and micro-area composition changing of cermets with different contents of NbC, ring structure becomes more complete and bonding phase becomes more uniformly distributed with the increasing of NbC content. The different contents of TiC and NbC can influence solution and diffusion, so it brings about variety of volume fraction of ring structure and the distribution of elements. Mechanical performance test shows that when the mass ratio of Ti(C,N) /TiC is 3:2, cermets adding 6wt% of NbC manifests the better comprehensive mechanical properties.Adding of various kinds of microcontent boride on the structural constituent and properties of cermets were researched. Because TiB2 and TiC are difficult in solution reaction in the liquid phase sintering process, Atomic arrangement cannot stack most closely and achieve combine in the crystal face; in addition, MoB and some intermetallic compounds appeared, eventually bend strength and fracture toughness decline, but vickers hardness was improved. To compare of the effect of various additives, when the content of TiB2 is 0.064wt%, it has good comprehensive mechanical properties.The effect of TaC and NbC were compared. In the system of Ti( C, N) based cermets without tungsten and cobalt, the dissolution rate of NbC is quicker than TaC's, it restrains hard phase growing up more stronger; moreover, NbC is more easier to occur solution reaction with Ti(C,N) in the liquid phase sintering, in a word, adding NbC is better than TaC.Finally, three kinds of blades of milling performance were investigated. It can be seen that the failure of blades were main flank wear, Rake face wear were main crater wear. The spread of crater and hot cracking lead to chipping blade. Two different hardness of 42CrMo workpieces were milled in high speed, when mill the lower hardness workpiece, milling performance of the blade with 6wt% of NbC was nearly to YNG151; when mill the higher hardness workpiece , the cutting life of two blades which were made in this research reduced, and these blades occured chipping blade in various degree. Fracture toughness should be improved in the future.