Preparation and cutting performance study of YSZ-toughened PcBN superhard tools

Abstract

Titanium alloy, as a recognized difficult-to-cut material, places higher demands on the performance of cutting tools. Compared with the mainstream cemented carbide tools, PcBN tools have a higher life and better machining performance. In this paper, a new type of cubic boron nitride superhard tool was prepared by introducing Y₂O₃-stabilized ZrO₂ (YSZ) under high temperature and high pressure (1500 °C, 5.5 GPa), and the effect of the variation of YSZ addition on the mechanical properties of the tool was systematically analyzed, and the cutting performance of the tool was also analyzed by cutting TC4. It was found that a small amount of YSZ addition, which generated a sub-stable t-ZrO₂ phase during the sintering process, could improve the mechanical properties of the tool and increase its cutting life. When YSZ was added at 5 wt%, the flexural strength and fracture toughness of the composites reached the maximum values of 637.77 MPa and 7.18 MPa m^1/2, while the cutting life of the tools reached the maximum value of 2615.81 m. And when YSZ was added at 2.5 wt%, the hardness of the material reached the maximum value of 43.62 GPa.