New Insight into the Effect of Alloying Elements on Elastic Behavior, Hardness, and Thermodynamic Properties of Ru₂B₃

How to improve the mechanical and thermodynamic properties is still a big challenge for transition metal borides. Alloying method is a good route based on the valence electronic discrepancy. However, the mechanism of alloying addition is unknown. In this article, the influence of alloying elements (TM = Mo, W, Os, and Re) on the structural stability, elastic properties, hardness, and thermodynamic properties of Ru 2 B 3 is studied by first-principles approach. Phonon dispersion, elastic properties, hardness, electronic structure, Debye temperature, and heat capacity of Ru 2 B 3 with alloying elements are calculated. It is found that Ru 2 B 3 with alloying elements are thermodynamic stability and dynamic stability at the ground state. We predicted that the alloying elements can improve the elastic properties and hardness for Ru 2 B 3 . Owing to the high valence electronic density, the shear deformation resistance of Ru 2 B 3 with alloying elements of Re and W is up to 12.7% and 11.1% in comparison with the perfect Ru 2 B 3 . We suggested that heavy alloying elements can result in charge transfer from TM atom to B atom and forms the strong B–B covalent bond. Finally, we concluded that alloying can improve the Debye temperature for Ru 2 B 3 .