The structural,mechanical, and thermodynamic properties of B2-type TMZr (TM = Ru,Mo, Rh,Os, and Re) compounds from first-principles calculations

The B2-type cubic Zr-based compounds are attractive advanced high-temperature materials because of the strong and symmetrical bonds. However, the mechanical and thermodynamic properties of the B2-type cubic Zr-based compounds are not well understood. Here, we use the first-principles calculations to investigate the structural, elastic modulus, ductility, and thermodynamic properties of TMZr (TM = Ru, Mo, Rh, Os, and Re) compounds. Two novel TMZr compounds, MoZr and ReZr, are first predicted by using the phonon dispersion and formation enthalpy, respectively. The results show that the B2-type TMZr compounds not only exhibit high elastic modulus but also show better ductility due to the symmetrical TM-Zr metallic bonds. In particular, the calculated elastic modulus of OsZr is larger than that of the other four TMZr compounds, indicating that the OsZr shows the strongest deformation resistance in five TMZr compounds. The calculated Θ _D of RuZr is 328 K, which is larger than that of the other four TMZr compounds. The calculated phonon density of state shows that the high-temperature thermodynamic properties of TMZr derive from the vibration of Zr atom. Therefore, our work predicts that the B2-type OsZr is an attractive high-temperature structural material.