This blog is about a paper by Sahu, et al. (202)
Sahu, V. K., Tripathy, S., Jena, P. S. M., Krishna, M. V., Chowdhury, S. G., & Mandal, G. K., On the experimental validation of a local equilibria based framework for design of Fe-C-Cr alloys exhibiting predicted partitioning behaviour during pearlite formation Materials Characterization. 2025 Jul 1;225:115143.
The claim is that on transformation of Fe-0.83C-0.34Cr wt% alloy to pearlite at 680°C, growth occurs by a the negligible-partitioning local equilibrium mechanism (NPLE).
Figure 8 is used to support the argument, but in fact it shows that the cementite in the vicinity of the growth front has a significantly larger average Cr concentration, all the way up to the marked interface position.
According to Figure 3, and consistent with NPLE, there should be a depletion in Cr in the austenite in contact with cementite, to 0.1 wt%, and an enrichment in the austenite that is in contact with ferrite, to 1 wt% Cr. Neither of these spikes are detected with the claimed chemical analysis resolution of 1 nm. The authors do not provide calculated widths or shapes of the concentration profiles.
My conclusion is that the fundamental parameters needed to establish NPLE have not been tested.
More information in Some difficulties in the theory of diffusion-controlled growth in substitutionally alloyed steels