Interface energy anisotropy and interface step structure in γ-Ni/γ'-Ni3Al: An atomistic simulations perspective

S Ghosh and R Mukherjee and C Brandl, PHYSICAL REVIEW MATERIALS, 9, 103601 (2025).

DOI: 10.1103/csqw-lzsh

The anisotropy of interface energy, alongside coherency strain energy, is crucial in determining precipitate morphology and interface instabilities in superalloys. However, most experiments and mesoscale simulations assume isotropic interface energy, although the interface energy anisotropy is significant in Ni-based superalloys. While atomistic simulations have progressed, the whole orientation space of the coherent face-centeredcubic/L12 interface remains unexplored, especially for low-symmetry interface plane orientations. In the present work, we investigate the full interface plane orientation space of coherent interfaces of a binary Ni-based superalloy (Ni/Ni3Al) using molecular dynamics simulations, determining the full interface energy anisotropy. The unprecedented orientation resolution allows the identification of structural and energetic details, which can build the basis for identifying structural building blocks (step lines) explaining interface energy anisotropy. We propose a step-structure model of coherent interfaces and apply it to predict the interface energy anisotropy based on noninteracting steps on facets.

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