Composites of the cBN–Si3N4 system reinforced by SiCw for turning tools

Abstract

The cBN–Si3N4–SiCw composites with different SiCw contents up to 20 vol % have been produced at high pressure of 8.0 GPa and high temperature of 2500 K. It has been defined that the Young modulus of the composites were within 740–846 GPa, the Vickers hardness and fracture toughness values were 37.5–42.0 GPa and 11.4–12.9 MPa·m1/2, respectively. An important feature of the composite microstructure is the breaking of SiCw as a result of HPHT action. It has been shown that at the addition of 10 vol % SiCw to the structure of a cBN–Si3N4 composite the interrupted turning of hardened steel results in the flank wear reduction up to 20%.