Thermodynamic stability, electronic structure and mechanical properties of Mo-Re binary alloys: A first-principles calculations

Abstract

Using first-principles calculations, we have systematically studied thermodynamic stability, electronic structure and mechanical properties of Mo-Re binary alloys. The alloying element Re prefers to occupy the substitution position with a formation energy of 0.10 eV in Mo rather than the tetrahedron/octahedron interstitial position. The charge transfers are obviously present between Re and Mo atoms, which can be confirmed by the Bader charge analysis. The density of states (DOS) demonstrates that the d orbitals of Re and Mo atoms are hybridized, revealing that Re and its adjacent Mo atoms can form the directional bond containing covalent components. On the basis of above studies on the most stable occupancy structure, the mechanical quantities (the elastic constants Cij, bulk modulus B, Young’s modulus E, shear modulus G, Poisson’s ratio v, and B/G) have been analyzed for three Mo-Re alloys with the low Re content, which are Mo127Re1, Mo53Re1 and Mo15Re1, respectively. All these mechanical quantities of both Mo127Re1 and Mo53Re1 alloys are nearly the same as that of perfect Mo, while all these mechanical quantities of Mo15Re1 alloy are obviously larger or smaller than that of perfect Mo. This demonstrates that Mo15Re1 alloy has significantly different mechanical characteristics from Mo127Re1 and Mo53Re1 alloys as well as perfect Mo. These results can provide a significant reference for the application of Mo-Re alloys in future fusion fields.

Keywords

• Molybdenum
• Alloying element Re
• Electronic structure
• Mechanical properties
• First-principles calculations