采用热压烧结法制备了组成（体积分数，下同）为80% TiB₂-20% B₄C（TB2）和20% TiB₂-80% B₄C（TB8）的陶瓷并制成刀具，分别在切削速度为50 m·min^-1和150 m·min^-1下对Inconel 718合金进行切削加工，研究了陶瓷刀具的切削性能和磨损机制，并与YG硬质合金刀具的进行了对比。结果表明：TB2陶瓷的抗弯强度和维氏硬度均低于TB8陶瓷的，但断裂韧度比TB8陶瓷的高约26%；在两种切削速度下，TB2陶瓷刀具的寿命最长，约为TB8陶瓷刀具和YG硬质合金刀具的2倍；TB2陶瓷刀具后刀面和刀尖的磨损机制主要为黏结磨损，边界沟槽的形成机制主要为轻微崩刃和冷焊层剥落；TB8陶瓷刀具后刀面和刀尖的磨损机制主要为崩刃，边界沟槽的形成机制主要为崩刃和冷焊层成片剥落。

80vol%TiB₂-20vol%B₄C (TB2) and 20vol%TiB₂-80vol%B₄C (TB8) ceramics were prepared by hot-pressed sintering and were made into cutting tools; the ceramic cutting tools were used to machine Inconel 718 alloy at cutting speeds of 50 m·min^-1 and 150 m·min^-1, respectively. The cutting performance and wear mechanism of the ceramic cutting tools were studied and compared with those of YG cemented carbide cutting tool. The results show that the flexural strength and Vickers hardness of TB2 ceramics were lower than those of TB8 ceramics while the fracture toughness was about 26% higher than that of TB8 ceramics. The life of TB2 ceramic cutting tool was the longest at the two cutting speeds, which was about twice that of TB8 ceramic cutting tool and YG cemented carbide cutting tool. The adhesive wear was the main mechanism for the wear of flank and tool tip of TB2 ceramic cutting tool; the grooves at boundaries were caused by slightly tipping and flaking of cold welding layer. The wear of flank and tool tip of the TB8 ceramic cutting tool mainly contributed to tipping; the formation of grooves at boundaries was due to tipping and large-pieced flaking of cold welding layer.