On the evolution of wave structure at the metal/oxide interface during oxidation of Zr alloys

• Model of evolution of a wavy metal/oxide interface has been proposed.
• The model is based on mechanical energy minimization.
• Fourier-analysis of experimental data shows existence of multiple harmonics.
• Experimental data can be explained by the model proposed.

Undulations of metal/oxide interface were determined in experiments during oxidation. Such structure can cause cracking near metal/oxide interface when a critical thickness of oxide film has been achieved. Cracking of the oxide leads to increase of metal oxidation rate and changes the oxide growth kinetics. In this paper conditions of the periodic structure parameters evolution have been determined based on minimization of mechanical stress energy appearing in the oxide film and the metal during oxidation. It has been shown that the process leading to increase of the wavelength near metal/oxide interface during oxidation can be the effect of period doubling bifurcation.