Assessment of atomic mobilities in the Al-Li fcc_A1 phase

Diffusion is one of the key factors that controls the precipitation of Al3Li metastable phase in Al-Li alloys. In this work, the diffusivity data in fcc Al-Li binary alloys available in the literature were comprehensively reviewed and critically evaluated, the diffusion mobilities of Al and Li in the Al-Li fcc_A1 phase were then assessed based on the reliable experimental data and empirical equations in the literature. An early relationship that correlates the diffusion activation energy and the melting temperature was revisited for group I elements, Li, Na, and K, and was used to predict the diffusivity of fcc Li. One set of self-consistent atomic mobility parameters for the Al-Li fcc_A1 phase was obtained. The limited reliable experimental diffusivity data can be generally reproduced by the present model parameters. In combination with the related thermodynamic description, the atomic mobility parameters were further verified by simulating the diffusion profiles of ion implanted Al samples at different annealing times. The model parameters were also used to simulate the concentration profiles of a cylindrical diffusion couple and the solidification process of an Al-3.5 wt.% Li alloy.