Modeling of hydrogen diffusion process at a blunt notch in zirconium

The two-dimensional diffusion of interstitial hydrogen atoms in zirconium in a non-uniform stress field was simulated using the phase-field method. The interaction between hydrogen interstitials and the stress field was described by Khachaturyan's elastic theory. The Cahn-Hilliard diffusion equation was then solved by an explicit finite difference method. The result shows that hydrogen atoms diffuse to the high-tensile hydrostatic region near the tip of the notch. The content of hydrogen near the tip of the notch increases by 13%, while the stress distribution caused by hydrogen interstitials around the notch is modified by only 0.7%.