Prediction of chromium depleted-zone evolution during aging of Ni–Cr–Fe alloys Original Research Article

The phenomenological and analytical study of depleted chromium zone in Ni–Cr–Fe alloys has been carried out in order to predict the evolution of chromium profiles resulting from carbide precipitation during aging. A diffusional model has been developed to take into account the two stages of chromium concentration evolution: dechromization and rechromization. The model has been verified using the available experimental data found in the literature for a nickel alloy type: Inconel 690. The changes of the chromium concentration at the carbide–matrix interface xiCr(t) and near the grain boundary xCr(x,t), as a function of annealing conditions, can be assessed with a reasonable accuracy by the proposed model and compared to the previous thermodynamic and kinetic models.