Formation of solid solution structures in (Ti,W,Ta,Mo)(C,N) cermet via spark plasma sintering

In this paper, a (Ti,W,Ta,Mo)(C,N) cermet material was prepared by spark plasma sintering. The formation of (Ti,W,Ta,Mo)(C,N) solid solution was characterized, and the effects of the sintering behavior and the binder content on the microstructure and mechanical properties of (Ti,W,Ta,Mo)(C,N) cermet materials were investigated. The results shown that a core-shell microstructure with cyclic gradient distribution was formed through the dissolution-reprecipitation mechanism, and the sintering behavior was improved and the relative density was increased. The optimized binder content can promote the dissolution and diffusion of Ti(C,N) particles. At the same time, the crack deflection and crack bridging caused by the core-shell microstructure improved the fracture toughness of the cermets, and the lattice distortion caused by fine grain and solid solution enhanced the flexural strength. When the binder content is 9 wt%, the mechanical properties of the cermet is better, the Vickers hardness, the flexural strength and the fracture toughness reach 18.17 ± 0.14 GPa, 1510.5 ± 47 MPa and 8.16 ± 0.40 MPa·m1/2, respectively. •In this paper, (Ti,W,Ta,Mo)(C,N) cermets with core-shell microstructure were sintered by spark plasma sintering.•The better densification degree was found when binder content was 9 wt%.•When the binder content is 9 wt%, the grain refinement and mechanical properties of the cermet is better.•The core-shell microstructure increased the crack deflection and improved toughness of cermet material.