Mechanical properties of ZrB2/SiC/WC ceramic tool materials from room temperature to 1100 °C and cutting performance

Abstract

ZrB2/SiC/WC ceramic tool materials with a WC content of up to 10 vol% were prepared using spark plasma sintering technology. The mechanical properties at room temperature showed that the ZrB2/SiC/WC ceramic tool material with a WC content of 5 vol% had the best comprehensive mechanical properties, with a hardness, flexural strength, and fracture toughness of 19.1 GPa, 590 MPa, and 4.9 MPa·m1/2, respectively. With the increase in temperature, the hardness and fracture toughness of the ZrB2/SiC/WC ceramic tool materials gradually decreased; however, the flexural strength first increased and then decreased. When the temperature was 600 °C, the flexural strength reached a maximum value of 630 GPa, which was an increase of 6.8% when compared to that at room temperature. The increase in flexural strength was mainly due to the increase in the transgranular fracturing during the fracture process of the ZrB2/SiC/WC ceramic tool material. Dry machining tests of 40Cr hardened steel were performed using ZrB2/SiC/WC ceramic tools. As the cutting speed increased, the tool life gradually decreased, but the surface quality of the workpiece gradually increased. When the cutting speed was 300 m/min, the tool life of the ZrB2/SiC/WC ceramic tool was 15.8 min, and the surface roughness Ra of the workpiece after cutting was between 1.0 and 2.0 μm. According to the wear morphology, adhesive wear was the main form of the ZrB2/SiC/WC ceramic tools.