Non-classical critical precipitates in a nucleation and growth regime: Reconciliation of simulation and experiment

International audienceIn this study, we have derived a method which consists in setting up and solving an original dynamics that provides critical precipitate characteristics, thus circumventing the theoretical difficulties encountered when modeling nucleation phenomena. Our model constitutes a substantial advance in this field as it enables critical nuclei characteristics to be determined irrespective of the energy barriers associated with the metastable state. Furthermore, the method is entirely consistent with the phase field approach, and in that respect, can be viewed as extending its applicability beyond the coarsening stage alone. The theoretical and numerical developments presented are assessed against original data obtained on an Fe-Cr alloy, used as a model system for studying nucleation and growth in the context of first order phase transitions