Tracking the evolution of microstructure and phases of WCoB-Co cermets during sintering

Transition metal boride enable applications in fields of cutting tools as the hard phase, but their fabrication suffers from shortcomings high temperature for binary and hard/soft phase balance. Here, we leveraged a WCoB-Co cermets prepared by using elemental powders W, Co B via situ synthesis method investigated microstructure evolution composite structure WCoB/Co. The evolution, mechanical properties were X-ray diffraction (XRD), differential scanning calorimetry (DSC), electron microscopy (SEM) energy dispersive spectrometer (EDS). complete sintering process consist three solid-phase reaction stages one liquid-phase stage. stage includes following reactions: + 2Co → Co2B, 11 W +15 Co2B 9WCoB W2Co21B6, 14 2W2Co21B6 12WCoB 23Co Co7W6. eutectic liquid essential densification, forms at 1323 °C. Rockwell hardness density value reach 87.5HRA 12.11 g/cm3, respectively. At 1380 °C, traverse rupture strength (TRS) reaches peak 1495 MPa. Moreover, results show that transgranular fracture is main mode. densification was completed ~1400 In particular, Co7W6 discovered during study cermets. An increase content found to be beneficial eliminate proved detrimental properties.