On the interplay between tungsten and tantalum atoms in Ni-based superalloys: An atom-probe tomographic and first-principles study

The partitioning behavior of W in a multicomponent Ni-based superalloy and in a ternary Ni–Al–W alloy is investigated using atom-probe tomography APT and first-principles calculations. APT observations indicate that whereas W partitions preferentially to the L12 -precipitates in the ternary alloy, its partitioning behavior is reversed in favor of the fcc -matrix in the multicomponent alloy. First-principles calculations of the substitutional formation energies of W and Ta predict that Ta has a larger driving force for partitioning to the phase than W. This implies that Ta displaces W from the -precipitates into the -matrix in multicomponent alloys. © 2009 American Institute of Physics. DOI: 10.1063/1.3073885