High-pressure high-temperature synthesis of WC-Co composites: overcoming the hardness-toughness trade-off through thermobaric processing

This study presents a novel high-pressure, high-temperature (HPHT) synthesis route for WC-Co cemented carbides, aiming to overcome the classic hardness-toughness trade-off. WC-Co composites were synthesized directly from elemental W, C, and Co under thermobaric conditions (4-8 GPa, 1200-2200 °C), enabling in situ WC formation and densification in a single step. Structural characterization (XRD, SEM, TEM), mechanical testing (hardness, fracture toughness, wear resistance), and electrophysical analysis (resistivity, magnetic saturation) were performed. The synthesized composites achieved 13-15 GPa hardness and 12-14 MPa·m 1/2 fracture toughness, surpassing typical WC-6Co grades (12-14 GPa hardness and 8-11 MPa·m 1/2 toughness). These findings demonstrate that HPHT synthesis yields dense, homogeneous WC-Co materials with superior balance of mechanical properties and thermal stability, providing a viable alternative to conventional sintering.