Partitioning of carbon from supersaturated ferrite plates

Abstract The time required for the diffusion of carbon out of suturated plates of ferrite, into the residual austenite, is investiagted using a finite difference model. The results are compare with an earlier approximate analytical solution. It is found that in all cases investigated, the analytical solution underestimates the diffusion time, the discrepany increasing at lower temperatures, or when the concentration of substitutional solutes which stabilise austenit is reduced. This is attributed to the fact that the analytical method fails to take account of the coupling of the diffusion fluxes that arise in both the austenite and the ferrite. The results are discussed in the context of displacive transformations in steels.