The γ' single phase interdiffusion in selected pseudo-binary sections of the Ni3Al-X (X = Cr, Fe, Nb and Ti) ternary alloys was studied at 1173 to 1533K in order to assess the influence of the site-preference of components upon their diffusion rate. It was observed that a higher fraction of Cr or Fe on the Al sub-lattice led to lower values of DXX(Ni). Both Ti and Nb, which strongly preferred the Al sub-lattice, exhibited significantly lower interdiffusion coefficients than did Fe and Cr. The equation, DXX(Ni) = DAlAl(Ni), held for Ti and Nb whereas the relationship, DXX(Ni) > DAlAl(Ni), was valid for Cr and Fe. The activation enthalpy of Qii(j) exhibited a systematic decrease with increasing valence electron number of the alloying element. It was noted that Nb exhibited a transient behavior. It had low values of diffusion coefficient as compared with its site occupation, but also a low activation energy.

Interdiffusion in Ternary Ni3Al/Ni3Al-X Diffusion Couples with X = Cr, Fe, Nb and Ti. J.Cermak, A.Gazda, V.Rothova: Intermetallics, 2003, 11[9], 939-46