Microstructure and characterization of WC-2.8 wt% Al2O3-6.8 wt% ZrO2 composites produced by spark plasma sintering

WC-Al2O3 and WC-ZrO2 composites in previous research suffered a trade-off between hardness and fracture toughness. Herein, it is found that combining 2.8 wf% Al2O3 and 6.8 wt% ZrO2 together in a WC composite, via spark plasma sintering, can produce both high hardness and high fracture toughness. The new composite was sintered at temperatures ranging from 1350 to 1600 degrees C, and the densification, phase constitution, microstructure, and mechanical properties of it were investigated. Surprisingly, the WC-2.8 wt% Al2O3-6.8 wt% ZrO2 composite achieved full densification at a low sintering temperature of 1400 degrees C. With a sintering temperature of 1450 degrees C, the optima hardness and fracture toughness were produced, 21.0 GPa and 8.5 MPa m(1/2), respectively. The mechanisms driving the low sintering temperature and well-combined mechanical properties of the composite were identified and explored. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.