Numerical Analysis of Internal Oxidation and Nitridation by the Cellular Automata Approach

In this study, the phenomena of internal oxidation and nitridation are modeled numerically by means of the cellular automata approach. As an example, TiN formation in Ni-base alloys was simulated by treating nitrogen diffusion and precipitation separately and simultaneously. It was shown that the concentration profiles of nitrogen diffusion are consistent with the analytical solution. The progress of internal nitridation follows a parabolic rate law in agreement with Wagner’s theory of internal oxidation and experimental results. Furthermore, the cellular automata approach is capable to predict the transition from internal precipitation to superficial scale formation and to implement the process of nucleation and growth of nitride and oxide precipitates.