Thermal diffusion coupled quantitative phase-field simulations with large undercooling

Abstract

The numerical solution of phase-field model depends on the input interface-width particularly when the undercooling is high. In order to make the computation feasible, the interface is required to be thick, but such choice of interface-width renders the numerical solution inaccurate. In the present work, we investigate the effect of interface-width on phase-field computation with thermal diffusion under high undercooling. We show that the accuracy of phase-field computation is actually related to the interfacial-energy. A numerical strategy based on mobility-correction is formulated and applied to the transformation of γ→α-iron under various conditions. We also numerically solve the moving-boundary model based on the sharp interface and compare it with the phase-field computations to assess its accuracy. It has been observed that convergence of the phase-field computations to sharp-interface based predictions is remarkably good with the proposed computational strategy over a wide ranges of input interface widths and undercoolings.