Effect of Ti3AlC2 content on microstructure and properties of PcBN materials

Abstract

The monolithic PcBN composite tool materials were prepared at 5.5 GPa and 1450 ℃ with different contents of Ti3AlC2 as the binder phase. The effects of different mass fractions of Ti3AlC2 on the phase composition, microstructure, and mechanical properties of PcBN tool materials were studied. The results show that Ti3AlC2 can decompose completely to form TiC and Al-Ti alloys under high temperature and high pressure, and reacts with cBN to form AlN, TiB2, and TiC0.7N0.3 phases. TiC, AlN, TiB2, and TiC0.7N0.3 are uniformly distributed around the cBN and tightly bonded to the cBN, thereby improving the mechanical properties of PcBN. When the mass fraction of Ti3AlC2 is 25 %, the relative density, bending strength, fracture toughness, and wear ratio of PcBN reach the maximum values, which are 98.9%, 592 MPa, 6.87 MPa·m1/2and 7 350, respectively. When the mass fraction of Ti3AlC2 is 20%, the microhardness of PcBN reaches the maximum value of 4 786.7 HV.

Keywords

• pcbn
• ti3alc2
• binder
• high temperature and high pressure(hthp)
• mechanical properties