Evaluation of Partitioning Ratios of Re Atoms in Ni-Al-Re-X (X : Cr, Mo, W, Ti, Ta, Nb, Co)Quaternary Alloys

Abstract

In order to examine alloying behaviour of rhenium (Re) and its effect on the properties of Ni-based superalloys, the partitioning ratio of Re atoms between the γ and the γ' phases and also the phase stability were investigated using Ni-Al-Re-X(X : Cr, Mo, W, Ti, Ta, Nb, Co) quaternary alloys. When those elements, X, which occupy preferably either Al sites or both Ni and Al sites in the Ni₃Al(γ') compound were added to the Ni-Al-Re ternary alloys, the trend of the partitioning of the Re atoms into the γ phase became considerably high in these alloys. Also, the compositional limit of a γ + γ' two phase region in the phase diagram was found to be 34 (mol%) for X(X : Mo, W, Ta, Nb) and 56 (mol%) for Ti in Ni-Al-Re-X quaternary alloys. The results on the partitioning ratio were analyzed with the alloying vectors.