  Based on the idea of maintaining physical diffuse interface kinetics,
enhancing interfacial diffusivity has recently provided a new direction for
quantitative phase-field simulation at microstructural length and time scale.
Establishing a general relationship between interface diffusivity and width is
vital to facilitate the practical application. However, it is still limited by
time-consuming numerical corrections, and its relationship with non-dilute
thermodynamic properties still needs to be revealed. In this study, we present
a new thermodynamic and analytical method for determining interfacial
diffusivity enhancement. Unlike previous numerical corrections of partition
coefficients and interface temperature, this new method aims to keep several
thermodynamic quantities unchanged after enlarging the interface width. These
essential quantities are theoretically proven to be diffusion potential jump
across the diffuse interface and free energy dissipation by trans-interface
diffusion. Since no dilute approximation has been employed in model derivation,
the present method is available for binary alloys with arbitrary thermodynamic
properties and can be easily extended to describe multicomponent systems.
Therefore, the present method is expected to advance the recent quantitative
phase-field framework and facilitate its practical applications.
