Diffusivity and Atomic Mobility in fcc Ni-Fe-V System: Experiment and Modeling

Abstract

In this work, the ternary diffusion behavior in fcc Ni-Fe-V system has been investigated by means of solid-state diffusion couple technique at 1000, 1100 and 1200 °C. The composition-dependent ternary interdiffusion coefficients were determined via Whittle-Green method, in which the uncertainties were calculated by error propagation and the reliability was validated via thermodynamic constraints. The ternary main interdiffusion coefficients of $$\tilde{D}_{\text{FeFe}}^{\text{Ni}}$$ and $$\tilde{D}_{\text{VV}}^{\text{Ni}}$$ were compared with the ones in binary Fe-Ni and Ni-V systems in the literature, respectively. The obtained interdiffusion coefficients combined with the thermodynamic description were employed to evaluate the atomic mobilities in fcc Ni-Fe-V system through the DICTRA (DIffusion-Controlled TRAnsformations) software package. A comprehensive comparison between the model-predicted diffusion behaviors and the experimental ones, including concentration/interdiffusion-flux distribution and diffusion path, confirms the reliability of the present atomic mobility. Besides, based on the presently obtained atomic mobilities, three-dimensional surfaces for the diagonal interdiffusivity at 1000, 1100 and 1200 °C were plotted. Furthermore, three-dimensional planes of the activation energy and frequency-factor of main interdiffusivities were evaluated using the Arrhenius equation. This work is part of our work to build a general kinetic database for soft magnetic alloys and cemented carbides.