Effect of Concentration-Dependent Diffusion Coefficient on the Migration of Interphase Boundaries

Abstract

The diffusion-controlled interphase-boundary migration problem is defined by a system of equations in which the boundary conditions for the diffusion equation are determined by capillarity. Numerical computer solutions to these equations were obtained for steady-state Widmanstätten ferrite plate growth. The effect of a concentration-dependent diffusion coefficient on the migration rate of some simple interphase boundary shapes was investigated. It was found that a constant diffusion coefficient corresponding to the weighted average coefficient in the matrix gave an exact growth rate.