Structural stability and mechanical properties of Pt–Zr alloys from first-principles

Highlights: • The convex hull indicates that Pt₁₁Zr₇ is the most stable structure. • Pt₈Zr has the strongest volume deformation resistance. • Pt₃Zr has the strongest shear deformation resistance and has highest stiffness. • The high elastic modulus originated from Pt concentration and bond characteristic. - Abstract: The correlation between structural stability and mechanical properties of Pt–Zr alloys is systematically investigated by first-principles calculations. Additionally, the thermodynamic properties and electronic structure are discussed in detail. The convex hull indicates that the Pt₁₀Zr₇ with orthorhombic structure is more stable than other Pt–Zr alloys at ground state. The bulk modulus of Pt–Zr alloys increases linearly as Pt concentration increases. Pt₈Zr has strong volume deformation resistance, which is derived from the high Pt concentration. Pt₃Zr exhibits strong shear deformation resistance and has high elastic stiffness, which originated from the strong Pt–Pt metallic bond along the b-direction. The trend of Debye temperature is consistent with the variation of shear modulus and Young's modulus, and the calculated Debye temperature of Pt₃Zr is 342 K, which is bigger than other Pt–Zr alloys. The results provide a helpful for the design of Pt-based high-temperature structural materials with excellent mechanical properties