Study On Performance And Organization Of Ultra-Fine (W,Ti,Ta)C Cemented Carbides

Ultrafine cemented carbide cutting tools are widely used in machining industry.With the development and renovation of material,the performance of cemented carbide cutting tools have been put forward more requirements.In this paper,different contents of Cr3C2,(W,Ti,Ta)C were doped in ultra-fine cemented carbides based on WC-6%Co,WC-8%Co and(VC / Cr3C2).The cemented carbides are preparad by researching the sintering temperature,sintering pressure and the ball grinding process,preparation process,adding inhibitor or(W,Ti,Ta)C.The results showed that the grain size of cemented carbides had no significant changement With Cr3C2 and(W,Ti,Ta)C increasing,the transverse rupture strength was decreasing,and hardness of cemented carbides was increasing In this test.The microstructure similar to twin was observed in WC-8%Co--0.5%(VC/Cr3C2)-4%(W,Ti,Ta)C cemented carbides by TEM.According to dispersive X-ray results,Cr3C2 and(W,Ti,Ta)C were validated.Under the certain condition temperature,the porosity could be decreased and relative density could be improved by Increasing pressure.Under the same pressure,the higher temperature is,the faster dissolution and diffusion velocity is,the more WC is dissolved,the faser speed that the fine WC move to the coarse WC is,it is more likely that abnormal grain WC appear.The WC-8%Co-0.5%(VC/Cr3C2)-4%(W,Ti,Ta)C cemented carbides which was prepared in pressure sintering at temperature of 1390? were achieved 99.7 % density,93.8 HRA hardness and 2250 MPa transverse rupture strength.The results also showed that the(W,Ti,Ta)C ultra-fine cemented carbides could be made by the method of milling the Composite powder of the(W,Ti,Ta)C and other powder At a certain milling time.