The Influence of Alloying Elements on Young’s Modulus Of γ- and γ'-Phases of Nickel-Based Superalloys. Review

This review considers the results of experimental and theoretical investigations of the influence of alloying elements on Young’s moduli of the γ(Ni)- and γ′(Ni 3 Al)-phases of nickel-based superalloys. The influence of alloying on Young’s moduli of the γ- and γ′-phases can be characterized by the coefficients dE^Ni/dcᵢ and dE^Ni_3Al/dcᵢ . A comparison of the results presented in literature shows that theoretical calculations of these coefficients based on first principles yield greatly overestimated values of the same sign. More realistic values can be obtained by molecular dynamics simulations. It is shown that the experimental values of dE^Ni/dcᵢ and dE^Ni_3Al/dcᵢ can be used to predict Young’s moduli of the γ- and γ′-phases of a nickel-based superalloy, as well as the alloy as a whole. In the present work, this was demonstrated for a nickel-based superalloy CMSX-4. The temperature dependences of Young’s moduli of this alloy and its γ- and γ′-phases were predicted and explained, the effect of γ′-phase dissolution was also shown.