Effect of Ni content on the microstructure and properties of WCoB-TiC cermets

To expand the applications of WCoB ternary borides in industry, the effect of Ni addition to WCoB-TiC cermets on their microstructures and properties was investigated in this study. Most of the Ni added was in the binder phase, forming a solid solution with Co. Although traces of Ni were dissolved in the hard phase, no new hard phase was generated. The thickness of the elongated hard phase increased with increasing Ni content. The sample with a Ni content of 15 wt% had the maximum Vickers hardness of 2102.5 HV0.5 at a fracture toughness of 9.84 MPa center dot m(1/2). The hardness and fracture toughness of the sample increased by 14.8% and 14.2%, respectively, when compared with the corresponding values of the sample with no added Ni. The fractures in the sample changed from intergranular fractures to a mixture of intergranular and transgranular fractures. The sample underwent abrasive wear; however, the change in its wear performance was not significant. The results indicate that the material can be toughened without significant impact on hardness and wear resistance.