A finite-difference model to predict 2D depletion profiles arising from high temperature oxidation of alloys

摘要

ODIN is a 2-D finite-difference diffusion/interdiffusion computer model capable of predicting the solute depletion profiles evolved in binary and ternary alloys due to high temperature oxidation. The 2-D geometries that can be analysed include corners, rectangular edges and rib features. Empirical mass gain kinetics in the form of a general power law are employed as a boundary condition to define the rate of removal of solute at the oxidizing surfaces of the alloy. The diffusion equations are then solved over the bulk region to obtain the resulting concentration profile at a series of discrete time steps up to the desired exposure time t. The model has been validated for planar foil-type 1-D geometries using existing analytical models which consider parabolic oxidation kinetics. The code predictions have also been compared satisfactorily against direct measurements of aluminium depletion near the 2-D edges of FeCrAlY steel samples.