Enhancement of Mechanical Properties of Low‐Density WC–TiC–Co Cemented Carbides

In this work, the effects of composition, carbide grain size, and WC matrix structure on the mechanical properties of low‐density WC–TiC–Co cemented carbides have been studied. It is found that increasing the TiC content promotes WC dissolution into TiC to form a (Ti,W)C solid solution. When the TiC particle size exceeds ≈2 μm, the sintered alloys exhibit a mixed microstructure of (Ti,W)C and core–shell‐structured (Ti,W)C@TiC grains. Refining TiC to the ultrafine scale eliminates the core–shell structures and generates a transition layer between WC and (Ti,W)C phases. This transition layer forms coherent and semi‐coherent interfaces with the adjacent carbides through lattice distortion and dislocation accommodation, which enhances interfacial bonding and increases intergranular fracture resistance. Furthermore, by incorporating ultrafine WC–Co composite powder to partially replace submicron WC, a bimodal grain microstructure is obtained in the sintered alloy, along with the formation of numerous Co‐rich nanoparticles within WC grains. The prepared WC–TiC–Co cemented carbides with optimized TiC content and particle size achieve reduced density and enhanced mechanical properties simultaneously. The present findings provide new insights into strengthening and toughening of low‐density cemented carbide materials.