First-principles modeling of superlattice intrinsic stacking fault energies in Ni3Al based alloys

Abstract

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Segregation-Assisted Plasticity in Ni-Based Superalloys

“…For the case of the lower energy faults (SISF-SESF), the segregation of solute species is believed to decrease the energy of these faults according to the published work in the literature. [26,27] Obviating quantitative deviations of the different concentration levels, the segregation patterns reported show no qualitative distinction between faults. This implies that the same segregation mechanisms are likely to be present regardless of the kind fault.…”

First-Principles Modeling of the Temperature Dependence for the Superlattice Intrinsic Stacking Fault Energies in L1$$_2$$ Ni$$_{75-x}$$X$$_x$$Al$$_{25}$$ Alloys

“…In fact, in our previous investigation 11 we have shown that the change in SISF energies as a function of alloying compositions, upon allowing local-atomic-relaxations, for the solutes Co, Cu, Pd and Pt is not significant, which is in contrast to the large increase induced by solutes substituting for Al sites. Consequently, it follows from the results presented here and Ref.…”

“…An alternative approach is to employ the Ising model to describe the energy of a large supercell as a sum of contributions arising from the interactions of pairs of planes 10 . Both methods have been used to compute various planar fault energies and the effect of composition on planar fault energies for γ -Ni 3 Al-based alloys 8,9,11 .…”

“…Thus, it becomes necessary to assess how these energies may change as temperature is increased. In our recent major work 11 , we have established the effect of composition on the SISF energies in all γ -Ni 3 Al-based alloys at 0 K. We have as well addressed the temperature effect on the SISF energies for several Ni 3 Al-based systems, specifically:…”

“…In this work, we try to establish the SISF energies variation as a function of temperature. The investigated alloys are those recently 11 addressed: (N i 75−x X x )Al 25 pseudo-binary system, where X = Co, Cu, Pd or Pt, and x= 4.62975, 9.2595, 13.88925 and 18.51825 at. % X.…”