Ternary interdiffusion coefficients in the γ-Ni and γ'-Ni3Al phases of the Ni-Al-Pt system at 1150C were determined experimentally by applying a Boltzmann-Matano method at a common composition in the time-invariant diffusion paths for a given two couples. The variation of the main-term interdiffusion coefficients of Al, DAlAlNi, with increasing of Pt content was different for the γ and γ' phases. In γ DAlAlNi generally increased with increasing Pt content, but it decreased with increase in Pt in γ' phase. By contrast, the main-term coefficients for Pt, DPtPtNi, apparently increased monotonically with increasing Pt content in both phases, but there was little dependency upon Al content. The cross-term interdiffusion coefficients, DAlPtNi and DPtAlNi, were negative in both γ and γ', showing that the chemical interaction between Al and Pt in these phases was negative. DAlPtNi values were larger than those of DPtAlNi; however, there was no clear dependence of DAlPtNi and DPtAlNi upon Pt and Al contents within the composition ranges studied. The cross-term interdiffusion coefficients were comparable to the main-term coefficients in γ and within an order of magnitude of each other in γ'. The significance of these findings were quantitatively assessed.

Interdiffusion in Pt-Containing γ-Ni and γ'-Ni3Al Alloys at 1150C. Hayashi, S., Sordelet, D.J., Walker, L.R., Gleeson, B.: Materials Transactions, 2008, 49[7], 1550-7