Electron microscopy study of Ni/Ni₃Al diffusion-couple interface-II. Diffusivity measurement

Interdiffusivities have been determined from compositional variations measured across the Ni/Ni₃Al diffusion-couple interface with an analytical electron microscope (AEM) and an electron probe microanalyser (EPMA). The AEM was used for measurement at lower temperatures and the EPMA was used at higher temperatures. The Boltzmann-Matano technique has been applied to the determination of interdiffusivities in the Ni-rich disordered phase and those in the Ni₃Al ordered phase. The interdiffusivities obtained in this study are compared with those reported in the literature including self-diffusivities and impurity diffusivities. It is shown that the present interdiffusivities are consistent with those predicted from the modified Darken's equation.