Research Of Gradient Cemented Carbide With A Depleted β Phase By Adding Ultra-fine TiCN Powder

Along with the fast development of high speed and precise manufacturing, high quality cutting tool is becoming more and more wanted. With the surface depleted cubic phase gradient cemented carbide (for short: depletedβphase gradient alloy) is a kind of good substrate material for CVD coating. The depletedβphase gradient can prevent the cracks caused by high temperature and stress in coating process by its depleted cubic phase ductile structure, which assures the excellent quality of coating tool.This thesis choosed the most important P30 alloy of cemented carbide as the research object, studied the depletedβphase gradient alloy prepared by adding Ti(C, N) or TiN powder in P30 alloy. Researched this gradient's sintering methods, forming mechanism, preparing process, affecting factors,coating quality and cutting performance by means of changing the method of adding N, alloy's composition, process parameters and coating the alloy. Studied the alloy'gradient with its composition, structure, element distribution, gradient thick, transverse rupture strength (TRS), coating-substrate appearance and adherence force of coating by the X-ray diffraction (XRD), scanning electron microscope(SEM) and cutting tests. First, added some 3μmTiN, 1.2μm TiC0.5N0.5, 0.13μm TiC0.5N0.5 powder in the P30 alloy respectively, with continuous sintering, in free-nitrogen atmosphere, attained different depletedβphase gradient alloy. Sintering temperature is 1440℃,sintering time is 1 hour. Metal graph investigation and XRD detection show that all the three...