[PO-F1] Poster Session 1

[P1-34] Transition-metal alloying of γ‘-Ni₃Al: Effects on the ideal uniaxial compressive strength from first-principles calculations

^○Minru Wen^2,1, Chongyu Wang² (1.Guangdong University of Technology, China, 2.Tsinghua University , China)

The addition of transition metal (TM) elements into the γ′ precipitate phase of a Ni-based single-crystal superalloy can significantly affect its mechanical properties, including the intrinsic mechanical property of compressive strength. Using first-principles density functional calculations, the effects of 3d (Sc-Zn), 4d (Y-Cd) and 5d (Hf-Au) TM alloying elements on the ideal uniaxial compressive strength of γ′-Ni₃Al were investigated. The stress-strain relationships of pure Ni₃Al under [100], [110] and [111] compressive loads and the site occupancy behavior of TM elements in Ni₃Al were prior studied using a total-energy method based on density functional theory. Our results showed that the capacity of TM elements for strengthening the ideal compressive strength was associated with the d-electron number. The alloying elements with half-filled d-bands (i.e., Cr, Mo, W, Tc and Re) manifested the greatest efficacy for improving the ideal strength of Ni₃Al under a deformation along the weakest compressive direction. Furthermore, the charge redistribution of Ni₃Al doped with 5d elements were also analyzed to understand the strengthening mechanisms of TM elements in the γ′-Ni₃Al phase.