| In this paper, Al2O3/TiC ceramic cutting tool materials with high mechanical properties by microwave sintering were fabricated by adjusting the forming pressure and improving the microwave sintering process parameters. The mechanical properties and microstructure of microwave sintering alumina matrix ceramic tool materials were analyzed. The cutting performance and wear mechanism of the microwave sintering alumina matrix ceramic cutting tools were studied.The relative density of green specimens increased as the forming pressure raised. When the forming pressure is 200MPa, the green specimen had optimal relative density. Its axial shrinkage and lateral shrinkage were 23.8% and 19.5%.The Al2O3/TiC ceramic cutting tool materials which were sintered at 1700℃for 10 minutes had optimal mechanical properties. Its Vickers hardness and fracture toughness were 21.2GPa and 5.18MPa·m1/2, respectively. Phase composition and microstructure analysis showed that the microwave sintered Al2O3/TiC micro-composites had a tendency to obtain a homogeneous microstructure in a short time, and restrain the reaction between Al2O3 and TiC.As for the machining of hardened alloy steel 40Cr, the tool life of AT is about 1.14～1.6 times of LT55 with the cutting depth ap=0.1mm and the feed f=0.1mm/r, but the wear resistance ability becomes poor when the feed is high. The main wear modes were tool wear on the rake face and flank, and the main wear mechanisms were bonding wear and abrasive wear.As for the machining of hardened alloy steel T10A, the tool life of AT is about 1.6 times of LT55 with the cutting speed v=104m/min, but the tool life of AT becomes lower when the cutting speed is high (v=155m/min). The main wear modes were tool wear on the rake face and flank, and the main wear mechanisms were bonding wear and abrasive wear. Fracture becomes more serious with the increasing of cutting speed.Moreover, there was diffusion wear on the flank under the high cutting speed (v=155m/min). |
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