Effects of Re/Os doping on the stability and mechanical properties of nickel-based single crystal superalloys: First-principles study

Abstract Based on first-principles calculations, by constructing a nickel-based γ/γ′ two-phase model with a γ′ phase volume fraction of 66.6%, the influence of Re/Os doping on the stability and mechanical properties of nickel-based single crystal alloys was studied. The results showed that at 0 K, the Re-doped model was more stable than the Os-doped model, and when the Re/Os doping content was 2.08%, both the γ/γ′-Re and γ/γ′-Os models exhibited the best structural stability. On this basis, the elastic properties and electronic structures of the γ/γ′-Re and γ/γ′-Os models were further calculated. It was found that both Re and Os form strong d-d hybridization with the d orbitals of Ni, resulting in covalent-like bonding, thereby enhancing the elastic properties of the nickel-based γ/γ′ two-phase model. Through comparative analysis of the elastic constants (C11、C12、C44) of the Re/Os doping models and the Young’s modulus and shear modulus along the [001], [110] and [111] crystal directions, it was found that the strengthening effects of Re and Os doping on the elastic properties of the nickel-based γ/γ′ two-phase model were similar. In addition, both the γ/γ′-Re and γ/γ′-Os models exhibited good toughness characteristics, and the Young’s modulus and shear modulus had significant anisotropy.