Cr3C2 and VC doped WC–Si3N4 composites prepared by spark plasma sintering

• Inhibitors do not hinder transformation of α–β-Si3N4 and growth of β-Si3N4 grains.
• Addition of Cr3C2 and VC shows an inhibitory effect against WC-grain growth.
• It is simple to obtain fine WC-matrix with well-developed elongated β-Si3N4 grains.
• Composite with inhibitors obtains higher hardness and comparative fracture toughness.

Cr3C2 and VC doped WC–10 wt.% Si3N4 composites were prepared by spark plasma sintering. The influences of Cr3C2 and VC on densification behavior, grain growth and mechanical properties of the WC–Si3N4 composites were investigated. During densification of the WC-based materials, the Cr3C2 and VC additives assist the preliminary densification of solid-state-sintering, and mitigate the subsequent densification of liquid-sintering. The addition of Cr3C2 and VC shows an inhibitory effect against WC-grain growth, resulting in higher hardness for the WC–Si3N4 composites. Moreover, the inhibitors do not hinder the transformation of α to β-Si3N4 and the growth of elongated β-Si3N4 grains, which act as toughening agent for the composites.