The site substitution behavior of Cr and Ta in the Ni3 Al (L 12) -type γ′ -precipitates of a Ni-Al-Cr-Ta alloy is investigated by atom-probe tomography (APT) and first-principles calculations. Measurements of the γ′ -phase composition by APT suggest that Al, Cr, and Ta share the Al sublattice sites of the γ′ -precipitates. The calculated substitutional energies of the solute atoms at the Ni and Al sublattice sites indicate that Ta has a strong preference for the Al sites, while Cr has a weak Al site preference. Furthermore, Ta is shown to replace Cr at the Al sublattice sites of the γ′ -precipitates, altering the elemental phase partitioning behavior of the Ni-Al-Cr-Ta alloy.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)