Probing the Structural Stability, Mechanical, Electronic, and Thermodynamic Properties of Mg–Y–Zn Ternary Compounds via First-Principles Calculations

Abstract

Magnesium alloys have large reserves and good strength, attracting a lot of attention. Herein, the thermodynamic, elastic constants, and electronic properties of the Mg-Y-Zn ternary compounds were calculated; among them, MgYZn₂ belongs to the cubic structure, MgYZn, Mg₃Y₂Zn₄, and Mg₁₄YZn-1 belong to the hexagonal structure, Mg₆YZn-1, Mg₆YZn-2, MgY₂Zn, and Mg₁₄YZn-2 possess the orthorhombic structure, and Mg₃Y₂Zn₃ is trigonal structure. The calculated cohesive energies of the results show that all compounds are thermodynamically stable. Moreover, the MgYZn₂ compound exhibits the highest modulus of 76.84 MPa, and the Mg₃Y₂Zn₃ has the biggest hardness of 6.6 GPa. In addition, the Mg₆YZn-2 has the strongest elastic anisotropic with A^U of 6.14 and A_G of 0.38, respectively. According to the population analysis, the Mg-Y covalent bond is due to the biggest bond population. The shortest weighted average bond length indicates that MgYZn₂ has better elastic properties. Furthermore, the calculated limiting thermal conductivity results show that Mg₁₄YZn-2 has better thermal conductivity with maximum values of 0.94 W·m⁻¹·K⁻¹ and 0.74 W·m⁻¹·K⁻¹ for Clarke’s and Cahill’s models.