Theoretical prediction of microstructure evolution during the internal oxidation fabrication of metal-oxide composites: the case of Cu–Al2O3

Abstract

We report a systematic strategy for theoretically characterizing the interface-level microstructure evolution during in situ internal oxidation of the metal-oxide composite Cu–Al₂O₃. First, the interface phase stability diagram and phase diagram are constructed from first principles based on thermodynamics calculations, to predict the equilibrium structures and corresponding energetics of the internal interfaces as a function of thermodynamic oxidation parameters (i.e. the ambient oxygen partial pressure and temperature). Further, the equilibrium solubility of oxygen in Cu is coupled with diffusion kinetics derivations, to find a way to connect between the ambient oxygen partial pressure and the local internal oxygen activity in the matrix. Eventually, by combining both thermodynamic and kinetic calculations, the microstructure evolution with time during the internal oxidation fabrication can be predicted at interface level for any practical internal oxidation conditions, such as using the oxidizer Cu₂O.