Microstructure and strengthening mechanism of Mo@Ni reinforcement (W,Ti)C cermet via spark plasma sintering

A new type of Mo@Ni reinforcement (W,Ti)C cermet was prepared by spark plasma sintering. The solution strengthening mechanism of the Mo@Ni reinforcement (W,Ti)C cermet was investigated. The results showed that proper holding time and sintering pressure could achieve a solid solution between the metal and ceramic phases. Under a sintering temperature of 1325 °C and a heating rate of 400 °C/min, the optimal holding time and sintering pressure of the (W,Ti)C cermet were 10 min and 20 MPa, respectively. Under these conditions, the flexural strength, fracture toughness, and Vickers hardness of the material reached 1550 ± 34 MPa, 12.35 ± 0.31 MPa m 1/2 , and 17.54 ± 0.33 GPa, respectively. The formation of a braided structure at the grain boundary increased the grain boundary strength and the bond strength between the grains; additionally, it increased the relative density, decreased the microstructure flaws, and made the grain size of the material fine and homogeneous.