Effect of the TiC-TiB2-AlN system on properties of PCBN tool material

Abstract

Polycrystalline cubic boron nitride (PCBN) materials were prepared to use cBN, TiC, Ti, and Al as raw materials under high temperatures and high pressures with varying sintering temperatures (1300–1600 °C) and holding times (6–15 min). The study analysed the reaction synthesis mechanism and interface bonding state of the PCBN materials and investigated the effects of sintering temperature and holding time on the mechanical properties and cutting performance of the PCBN materials. The results show that under high-temperature and high-pressure conditions, metal atoms' diffusion was accelerated, allowing the binder and cBN to react quickly, forming a new binding phase The new bonding phase had a strong bond between the cBN grains of PCBN, resulting in a dense composite material with excellent mechanical properties. The PCBN material's mechanical properties initially increased and then weakened with an increase in sintering temperature. At 1500 °C, the material's flexural strength and hardness reached 970.9 MPa and 3489.2 Hv, respectively. The mechanical properties of the PCBN material increased with an increase in holding time, with a holding time of 15 min resulting in flexural strength and hardness of 980.2 MPa and 3529.1 Hv, respectively. The PCBN tool material prepared at 1500 °C and 12-min holding time exhibited the best cutting performance. During a 10 km cutting length of cast iron, the tool wear was only 0.26 mm.