D Jianxin et al. / International Journal of Machine Tools Manufacture 45(2005)1393-1401 be attributed to the mechanical impact, transient thermal stresses. and excessive crater and flank wear Thus, the ceramic tools are not suitable for machining of Inconel718 nickel-based alloys with a cutting speed higher than 150 m/min 4. Conclusions AlO/TiB,/SiCw ceramic cutting tools volume fraction of TiB2 particles and Sic whiskers were produced by hot pressing. Machining tests with these ceramic tools were carried out on the Inconel718 nickel based alloys. Results showed that Fig. 9. Effect of cutting speed on the cutting temperatures of ABW20 ceramic tool when machining Inconel718 nickel-based alloys 1. The fracture toughness and hardness of the tool materials continuously increased with increasing Fig. 12 shows the SEM micrograph of the tool wear profile SiCw content up to 30 vol %. The relative density ABW20 ceramic tool at a cutting speed of 180 m/min decreased with increasing Sic whisker content, It can be seen that both the tool tip and the cutting edges were the trend of the flexural strength being the same as that broken down completely under these test conditions. This may of the relative density. Imm Fig. 10. SEM micrographs of the worn rake face of ABw20 ceramic cutting tool when machining Inconel718 nickel-based alloys(a)v=100 m/min,(b)v 120 m/min, (c)enlarged SEM micrograph corresponding to(a).Fig. 12 shows the SEM micrograph of the tool wear profile of ABW20 ceramic tool at a cutting speed of 180 m/min. It can be seen that both the tool tip and the cutting edges were broken down completely under these test conditions. This may be attributed to the mechanical impact, transient thermal stresses, and excessive crater and flank wear. Thus, the ceramic tools are not suitable for machining of Inconel718 nickel-based alloys with a cutting speed higher than 150 m/min. 4. Conclusions Al2O3/TiB2/SiCw ceramic cutting tools with different volume fraction of TiB2 particles and SiC whiskers were produced by hot pressing. Machining tests with these ceramic tools were carried out on the Inconel718 nickel￾based alloys. Results showed that 1. The fracture toughness and hardness of the composite tool materials continuously increased with increasing SiCw content up to 30 vol.%. The relative density decreased with increasing SiC whisker content, the trend of the flexural strength being the same as that of the relative density. Fig. 9. Effect of cutting speed on the cutting temperatures of ABW20 ceramic tool when machining Inconel718 nickel-based alloys. Fig. 10. SEM micrographs of the worn rake face of ABW20 ceramic cutting tool when machining Inconel718 nickel-based alloys (a) vZ100 m/min, (b) vZ 120 m/min, (c) enlarged SEM micrograph corresponding to (a). D. Jianxin et al. / International Journal of Machine Tools & Manufacture 45 (2005) 1393–1401 1399