First-principles calculations of intrinsic stacking fault energies and elastic properties in binary nickel alloys

Density Functional Theory based first-principles calculations were performed to determine the compositional variation of the intrinsic stacking fault energy (ISFE) and the elastic properties in Ni-based concentrated alloys, modeled as chemically disordered solid solutions. Most of the solutes reduce the ISFE of the nickel matrix, where elements characterized by half or near half d -band filling (Mo, V, Tc, Ru, Cr, Os, Re, W) are predicted to produce the highest decline rates of the ISFE. The decisive role played by chemical short range order in determining the ISFE in Ni-based multicomponent y phase alloys is discussed. Osmium is predicted to improve the elastic moduli of the fcc Ni matrix. Osmium high ISFE decline rate and excellent elastic moduli make it a potent element improving the mechanical properties of Ni-based super and multi -principal element alloys. This role seems to have been identified in a recently developed osmium-containing Ni-based superalloy, see Wei et al . (2022).