The diffusion of Al and Ni in the L12-type phase was examined by measuring the intrinsic diffusion coefficients. Interdiffusion coefficients were first determined by using Ni/NiAl diffusion couples which formed Ni3Al phase at the interface. The intrinsic diffusion coefficients were then deduced, via the Darken equations, from the interdiffusion coefficients and the velocities of the Kirkendall interface with respect to the Matano plane. It was shown that the intrinsic diffusion coefficients of Al and Ni in Ni3Al were of almost equal magnitude at 1423 to 1523K. The self-diffusion coefficient of Al in Ni3Al was obtained from the intrinsic diffusion coefficients of Al and Ni in Ni3Al. It was shown that the present results supported diffusion mechanisms which involved antisite defects.

Measurement of Intrinsic Diffusion Coefficients of Al and Ni in Ni3Al using Ni/NiAl Diffusion Couples. Fujiwara, K., Horita, Z.: Acta Materialia, 2002, 50[6], 1571-9