Effect of Cr3C2 on the microstructure and properties of TiWMoC-based cermets

Effect of Cr3C2 on the microstructure and mechanical properties of TiWMoC-based cermets were studied. The microstructure was investigated by using x-ray diffraction (XRD) and scanning electron microscope (SEM) in combination with energy dispersive spectrometry (EDS). Mechanical properties of transverse rupture strength (TRS), fracture toughness (K-IC) and Vickers hardness (HV) were measured. The results show that Cr3C2 mainly dissolved in the binder phase and the dissolution of Cr3C2 into the binder phase reduced the solubility of TiC, WC, and Mo2C. As the Cr3C2 addition increased from 0.4 wt% to 1.2 wt%, the proportion of black core with medium grains increased with a concomitant decrease of coarse grains. Additional dimples appeared in the fracture surface. The porosity decreased with the increase of Cr3C2 addition, and the mechanical properties of TiWMoC-based cermets were improved. However, owing to decreased solubility of TiC in the binder phase, some coarse grains formed with thicker rims. The crack propagation path became a transgranular fracture-led model, the porosity increased and the mechanical properties decreased. The cermet with 1.2 wt% of Cr3C2 demonstrated better mechanical properties.