The influence of high pressure on the structural stability, Vickers hardness and mechanical properties of Re and Ru dodecaborides

Abstract

We apply the first-principles approach to study the structural stability, Vickers hardness, and elastic modulus of ReB 12 and RuB 12 . In particular, we further investigate the influence of high pressure on the structural stability and mechanical properties of ReB 12 and RuB 12 . The calculated results show that ReB 12 and RuB 12 are thermodynamic stability under high pressure. Here, ReB 12 is more thermodynamic stability than that of the RuB 12 . The calculated Vickers hardness of ReB 12 and RuB 12 is 16.25 and 16.55 GPa, respectively. It is found that the calculated elastic constants and elastic modulus of ReB 12 and RuB 12 increase with increasing pressure. In particular, the calculated elastic constants and elastic modulus of ReB 12 are larger than that of the RuB 12 . The calculated electronic structure shows that the high hardness and elastic modulus of ReB 12 and RuB 12 are attributed to the 3D network B-B covalent bonds. K E Y W O R D Sfirst-principles calculations, hardness, mechanical properties, ReB 12 , RuB 12 , superhard materials

The structure and multifunctionality of high-boron transition metal borides *

“…As shown in figures 5(a) and (b), in these two structures, TM atoms are surrounded by B 24 cages, and B 12 clusters are also found inside these two structures, which are all cubic octahedrons (right of figures 5(a) and (b)). The difference is that the B 24 cage forms a face-centered cubic structure with TM atoms in the UB 12 structure, while ScB 12 forms a bodycentered cubic structure [17,86,[99][100][101][102][103][104][105][106][107][108][109]. Besides, a 2D structure of TiB 12 was also predicted in 2017.…”