Abstract：PCBN composites were prepared by sintering rare earth Eu2O3 and Pr2O3 as additives in the cBN-Al-Ti
system at high temperature（1600 ℃）and high pressure（5.5 GPa）. The effects of rare earth on the phase，microstructure，
porosity and mechanical properties of PcBN were studied. The results show that the addition of Eu2O3
and Pr2O3 not only improves the morphology of the reinforced phase TiB2 and reduces the porosity of the sample，but
also increases the hardness and bending strength of the sintered body. When adding rare earth Pr2O3，PCBN obtains
the best mechanical properties，its microhardness reaches 40.15 GPa，and its bending strength reaches 801.24 MPa.
2020, Vol. 30 
