Exploring the Impact of Zirconium Doping on the Mechanical and Thermodynamic Characteristics of Pt-40Rh Alloy through First-Principles Calculations

Abstract

Zirconium (Zr) element doping has proven to be an effective strategy for reinforcing the strength and toughness of Pt-Rh alloys. However, the incorporation of Zr into Pt-Rh alloy in solid solution form renders its microstructural observation challenging through experimental means, thus complicating the elucidation of its underlying mechanisms. Therefore, this study employs density functional theory-based first-principles calculations to investigate the mechanical and thermodynamic properties of Pt-40Rh-xZr (x = 0, 0.1, 0.5, 1.0) alloys. The results reveal that with an increasing Zr weight percentage, Young’s modulus, and hardness of Pt-40Rh-xZr alloys exhibit a trend of an initial decrease followed by a subsequent increase. Notably, at a Zr weight percentage of 1.0 wt.%, the alloy Pt-40Rh-1.0Zr demonstrates the highest Young’s modulus (329.119 GPa) and hardness (10.590 GPa). Concurrently, thermodynamic calculations indicate that as Zr content increases, the crystal thermal stability of Pt-40Rh-xZr alloys initially decreases before rising again. More specifically, the coefficient of thermal expansion for Pt-40Rh-1.0Zr is merely 89.518% of that observed in Pt-40Rh. These results imply that incorporating 1.0 wt.% Zr results in the most substantial enhancement in the comprehensive mechanical properties of the Pt-40Rh-xZr alloy. Consequently, this study offers theoretical insights that can guide the extended application of Pt-Rh alloys.