Partitioning of carbon from supersaturated ferrite plates

S. A. Mujahid and H. K. D. H. Bhadeshia
University of Cambridge


The time required for the diffusion of carbon out of supersaturated plates of ferrite, into the residual austenite, is investigated using a finite difference model. The results are compared with an earlier approximate analytical solution. It is found that in all the cases investigated, the analytical solution underestimates the diffusion time, the discrepancy increasing at lower temperatures, or when the concentration of substitutional solutes which stabilise austenite 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.

Acta Metallurgica et Materialia, Vol. 40, 1992, pp. 389-396.