Phase-field simulation of diffusion couples
Linking thermodynamic and atomic mobility databases with two-dimensional phase-field simulation, the evolution of interdiffusion microstructures in a series of Ni–Al diffusion couples associated with γ, γ', and β was studied. The formation and subsequent growth of the γ' phase layer in β/γ and γ'+β/γ diffusion couples were well reproduced, compared with the experimental observations. Moreover, the effect of coherent strain on the γ–γ' microstructural evolution, as well as that of external compressive force on the γ+γ'/γ+γ' diffusion couple, was investigated. The phase-field simulated concentration profiles of some Ni–Al diffusion couples were also compared with the corresponding experimental data, as well as one-dimensional DICTRA (Diffusion Controlled TRAnsformations) simulations. The discussion on the rafting direction was also made by comprehensively comparing the phase-field simulations with the predicted results from the elastic model.