| Al2O3 ceramic has excellent high temperature strength, wear resistance and corrosion resistance, the nanometer powder can further reduce the sintering temperature, but low strength at room temperature and low fracture toughness limit its development. AI2O3 will greatly improve the material performance by hot-pressing sintering when Adding carbide or nitride. Ti(C,N) is a continuous solid solution of TiC and TiN, it takes both the good performance, it could hinder the Al2O3 grain from growing, it have the effect of enhancing toughness. ZrO2 phase transformation is an effective way of increasing toughness for ceramic. It could hinder crack propagation by t-ZrO2?m-ZrO2 phase transformation, which reinforce toughness. cBN as a new kind of super hard material, its structure is similar to diamond, and its hardness is second only to diamond, it has good heat stability, its heat resistant is up to 1400?-1500?, it has good chemical stability, it won't be oxidized below 1000?. Under 1200-1300?, it has no chemical reaction with iron series material, cBN also has good thermal conductivity and small friction factor, it can improve the cutting performance of the cutting tools.This paper studies the effect of ZiO2 content and hot-pressing temperature on Al2O3-Ti(C,N)-ZrO2 composite materials. Results show that, when the content of ZiO2 is 10vol.%, press is 44 MPa, hot-pressing temperature is 1200?, time of heat preservation for is 15min, the optimum comprehensive mechanical properties of composite is observed, the relative density is 99.8%, Vickers hardness is 21.5 GPa, fracture toughness is 5.13 MPam"2.Prepare the Al2O3-Ti(C,N)-cBN composite materials by hot pressing technology. This paper studies the effect of different hot pressing process and cBN content on the composite materials. Results indicate that, when the cBN content is 5vol.%, hot-pressing temperature is 1450?, pressure is 44 MPa, heat preservation time for 30 minutes, the composite material has best comprehensive mechanical properties, the relative density of 99.9%, Vickers hardness of 22 GPa. And with the increase of content of cBN, relative density and hardness of the composites decrease, when the temperature is over 1550?, the change of cBN to hBN will occur.Respectively use Al2O3-Ti(C,N)cutting tools and Al2O3-Ti(C,N)-cBN cutting tools for TC4 titanium alloy's machining, the wear morphology of the cutting tools under different cutting parameters is studied and the surface roughness of the workpiece is detected. The results show that, the Al2O3-Ti(C,N)-cBN composite ceramic blade could process TC4 titanium alloy without apparent collapse, but micro crack edge phenomenon, with the increase of cutting speed, the wear of back-surface area increased. The Al2O3-Ti(C,N)-cBN cutting tools with 5vol.% cBN has better wear resistance than the Al2O3-Ti(C,N) composite without cBN under the condition of high speed continuous dry cutting, the main wear modality of Al2O3-Ti(C,N)-cBN composite is flank surface abrasion of the cutting tool, and the wear area is narrow with a small chamfering radius R. the add of cutting fluid has advantage for ceramic cutting tools than dry cutting, both the surface roughness and the wear is reduced. |
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