Interdiffusion in intermetallic samples which were alloyed with 0 to 19at%Co was studied on 3 pseudo-binary sections: cAl = 22, cCo = 3.5 and cCo = 16at%. The experiments were carried out at 1173 to 1473K. An attempt was made to resolve the interdiffusion coefficient into the intrinsic diffusivities of individual components. Since no detectable shift of W inert markers was observed, it was concluded that the intrinsic diffusivities of element pairs with varying concentration (Al/Ni and Co/Ni) on pseudo-binary sections were approximately equal. The interdiffusion in Al/Ni pseudo-binary alloys (cCo constant) was slightly faster than that in Ni/Co pseudo-binary alloys (cAl constant). The relationships between the measured interdiffusion coefficients in the Ni3-xAlCox ordered γ’ phase agreed well with published data on interdiffusion coefficients in the ordered γ’ and γ’-Co phases and also in disordered Al–Ni and Co–Ni solid solutions. They were qualitatively explained by mutual interactions between the constituents and by their interactions with vacancies.

Interdiffusion in Pseudobinary Sections of Ni3Al-Co Ternary System. Gazda, A., Rothova, V., Cermak, J.: Intermetallics, 2002, 10[9], 859-64