Effect of plasma sintering preparation process on the mechanical properties of WC/Cr3C2/La2O3 cutting tool materials

Traditional cemented carbide tools with binder phase is easy to be worn under high-speed cutting. In order to improve tool life, WC/Cr3C2/La2O3 cemented carbide without binder phase was prepared by Spark Plasma Sintering.The effect of chromium carbide content, sintering process on the microstructure and properties of sintered specimens were investigated. After testing the samples prepared at Cr3C2 content of 0 wt%~2 wt%, sintering temperature of 1550 ℃~1550 ℃ and sintering pressure of 15 MPa~45 MPa, respectively, the results show that the optimum chromium carbide content is 0.5 wt%. WC/Cr3C2/La2O3 cemented carbide sintered at 1550 ℃ and 25 MPa has the best comprehensive properties.The density, Vickers hardness and bending strength are 97.5%, 2124.3HV and1281.0 MPa, respectively. With the increase of sintering temperature, the density increases and microstructure becomes more even for WC-based tool materials. However, too high temperature leads to abnormal growth of grains, uneven distribution of microstructure, more porosity and lower mechanical properties.As sintering pressure increases, the size of the grains reduces, the microstructure is more even and mechanical properties increase. While sintering pressure is above 25 MPa, mechanical properties of tool materials decrease.