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Diffusion and Stress Coupling Effect during Oxidation at High Temperature

Xue Feng (Tsinghua University)

Materials for Extreme Environments: Multiscale Experiments and Simulations

Mon 10:45 - 12:15

Salomon 203

Oxidation of materials at high temperature is the key issue for thermal protection in extreme environments. We report the diffusion and stress coupling effect during oxidation. The experiment shows the micro-crack induced by oxide film stress, however, the micro-cracks did not accelerate the oxidation. An analytical model is developed for the stress and diffusion coupling effect based on equilibrium relationship and diffusion equation considering for the stress effect. Compressive stress will generate during the oxidation due to the growth strain. This growth stress can modify the diffusion coefficient therefore the oxidation kinetics is also affected. The coupling effect reduces both the oxidation rate and the stress.