Effect of Mo addition on the microstructure, fracture behavior and interface characteristics of faveolate Ti(C, N)-based cermets prepared by multiphase-flow agglomeration and subsequent vacuum sintering

Faveolate Ti(C, N)-based cermets with different Mo contents were prepared utilizing multiphase-flow agglomeration and subsequent liquid phase sintering. By precisely controlling the drying conditions, a multiphase flow was formed by the powders and liquid medium and bubbles generated when the slurry boiled, thereby achieving the agglomeration of particles. The impact of Mo content on the microstructure, interface characteristics and fracture behavior of cermets was investigated by XRD, SEM, EDS, TEM and fractal dimension. As the Mo content increased from 6 wt% to 14 wt%, the clear interface between the matrix and agglomerates gradually disappeared and the grains of cermets were refined. The volume fraction of agglomerates increased from 15.55 % to 20.93 % and then decreased to 19.49 % when the Mo content reached 14 wt%. There was a significant increase in the proportion of tearing ridges and dimples within the fracture morphology of both the matrix and the agglomerates showing the largest fractal dimension (2.345) in the sample with 12 wt% Mo. Moreover, cracks propagation path exhibited the largest fractal dimension (1.349) and a greater propensity to bridge or deflect, leading to more tortuous propagation paths that substantially consumed fracture energy. The faveolate cermet containing 12 wt% Mo demonstrated the most favorable mechanical properties, with TRS of 2422 ± 31 MPa, fracture toughness of 10.46 ± 0.15 MPa m^1/2, and hardness of 91.9 ± 0.2 HRA. The interface between the hard phase and the Ni phase in the agglomerates and the matrix both exhibited a coherent relationship, enhancing the properties of faveolate cermets.