Microstructure and mechanical properties of hot-pressed WC-MgO composites with Cr3C2 or VC addition

► VC or Cr3C2 addition improved the mechanical properties of WC-MgO composites. ► Indentation size effect was observed in the hardness measurement of WC-MgO composites. ► The load-independent hardness of WC-MgO composites was firstly calculated. ► Niihara's model was preferable for estimating the indentation fracture toughness.