Refractory Metals Enhanced the Mechanical and Thermodynamic Properties of B‐Rich Region YB₁₂ Borides

To improve the overall properties of YB 12 ceramics, the influence of refractory metals on the structural stability, Vicker hardness, elastic properties, elastic anisotropy, and thermodynamic properties of YB 12 boride is studied using first‐principles calculations. The result shows that the structural stability of TM‐doped YB 12 becomes better with decreasing the valence electronic density for these refractory metals. In particular, the calculated Vickers hardness of Re‐doped YB 12 is 40.2 GPa, which is higher than that of YB 12 (36.21 GPa) and the other TM‐doped YB 12 . The high hardness of TM‐doped YB 12 is demonstrated by the change of Poisson ratio (δ) and B/G ratio. Naturally, the high hardness of Re‐doped YB 12 is that the refractory metal enhances the localized hybridization between B and B atoms in B 12 cage, which is demonstrated by the change of the B–B covalent bond. In addition, YB 12 and TM‐doped YB 12 borides exhibit elastic isotropy. Finally, it is found that these refractory metals (except for Re) enhance the melting point of YB 12 .