First-principles calculations to investigate influence of transition metals TM (TM = Ti, Zr, Hf) on elastic properties and thermodynamic properties of ScB12 and YB12 dodecaborides

In present work, the first-principles calculations were adopted to investigate the influences of transition metals TM-doped on the structural, mechanical, and thermodynamic properties of ScB12 and YB12 dodecaborides. Three transition metals TM: Ti, Zr, and Hf were selected for present investigations. The thermodynamic data and phonon frequencies confirm that TM-doped models show the structural stability. According to the elastic constants and elastic moduli, these TM-doped transition metals weakened the mechanical strength of ScB12 and YB12, but well improve the brittle behavior of ScB12 and YB12. The elastic hardness of ScB12 and YB12 is weakened by the TM-doped transition metals. The electronic structure explains the essential mechanism. The TM-doped transition metals weaken the hybridization behavior of B-B, Sc-B, and Y-B atoms. The anisotropy of TM-doped models were illustrated by three-dimensional surface constructions. The thermal parameters show the effect of TM-doped on the thermodynamic properties of ScB12 and YB12 at elevated temperature.