Synthesis and characterization of cBN-Al2O3-Al cutting tool material by dual power spark plasma sintering

A cBN-Al2O3-Al cutting tool material was prepared by a dual power spark plasma sintering method, and the effects of sintering temperature, holding time and Al2O3 content on the microstructure and mechanical properties of cBN-Al2O3-Al cutting tool material were studied. The results showed that the dual power sintering method strengthened the spark plasma generated between the particles, increased the uniform discharge effect of the metal Al in the sintered body, generated a local high temperature and reacted with the activated cBN to produce AlN, and inhibited the phase change of cBN. When the sintering temperature was 1500 °C, the holding time was 5 min, and the pressure was 50 MPa, the overall mechanical properties of cBN-Al2O3-Al cutting tool material with 50 wt% Al2O3 content were the most optimal, with a hardness of 24.45 GPa, a fracture toughness of 5.92 MPa·m1/2, and a flexural strength of 423 MPa.