Rapid screening of alloy elements to improve the elastic properties of dilute Pt-based alloys: High-throughput first-principles calculations and modeling

Abstract

Platinum (Pt)-based dilute solid solutions are an important category of high-temperature alloys and bond coatings. In this study, the effects of 33 alloying elements on the mechanical and electronic properties of dilute Pt-based solid solutions are systematically investigated under atom relaxation and full relaxation using first-principles calculations based on density functional theory. The negative mixing enthalpy of Pt-dilute solid solutions means that the solubility of the solute elements in the Pt-based dilute alloys is energetically favorable at 0 K. Niobium, rhenium, and scandium are promising candidate elements for increasing the hardness and ductility of dilute Pt-based solid solutions. In addition, the electronic basis for the mechanical properties of Pt-dilute solid solutions is investigated in terms of the electronic density and mean bond population. The results demonstrate that the Pt–X bond lengths are shorter than the Pt–Pt bond length, resulting in greater hardness. Moreover, the model for the composition dependent elastic properties is built based on the CALPHAD approach, which will be used to the Pt-based multiphase alloys in the future. As certain alloying elements improve the hardness and ductility of Pt, this research expands our knowledge of the mechanism of dilute Pt-based solid solutions and provides a basis for next-generation superalloys or bond coatings at higher temperatures.