Study of Mo 3 NiB 3 and Mo 2 NiB 2 cermets by first-principles calculation and experiment

In this work, the mechanical properties of Mo 3 NiB 3 and Mo 2 NiB 2 phases in Mo-Ni-B cermets were studied. The first-principles calculation results demonstrate the thermodynamic and mechanical stability of both Mo 3 NiB 3 and Mo 2 NiB 2. Among them, Mo 2 NiB 2 shows superior stability and toughness compared to Mo 3 NiB 3. On the other hand, the Young’s modulus and hardness values of Mo 3 NiB 3 are higher than those of Mo 2 NiB 2. Mo 3 NiB 3 exhibits enhanced isotropy and stronger covalent bonding properties, as confirmed by DOS and Mulliken analysis. Further research shows that Mo 3 NiB 3 has brittleness (B/G = 1.586) and high Vickers hardness (22.3 GPa), indicating its potential use as a wear-resistant material. To validate the accuracy of the theoretical calculations, Mo 3 NiB 3 and Mo 2 NiB 2 cermets were fabricated through vacuum hot pressing sintering, followed by comprehensive analysis of their microstructure and mechanical properties. Specifically, the experimentally measured compressive strength and hardness values of Mo 3 NiB 3 (3213.2 MPa and 3264.2 HV0.3, respectively) were closely matched by the theoretical predictions. Notably, these experimental findings are in good agreement with the theoretically calculated values. This investigation provides reference value for a more in-depth analysis of the mechanical properties of Mo-Ni-B cermets, provides a theoretical and practical basis for its application in the field of materials, and promotes the development of Mo-Ni-B cermets materials.