Effect of applied load on nucleation and growth of γ-hydrides in zirconium

γ-hydride precipitation and growth in zirconium were investigated by using a phase-field kinetic model. The orientation difference of hydride is represented by non-conservative structural field variables, whereas the concentration difference of hydrogen in precipitates and matrix is described by a conserved field variable. The temporal evolution of the spatially dependent field variables is determined by numerically solving the time-dependent Ginzburg-Landau equations for the structural variables and the Cahn-Hilliard diffusion equation for the concentration variable. It is demonstrated that a certain load level is required to completely re-orient hydride precipitates and it is most effective to apply loads during the initial nucleation stage for producing anisotropic precipitate alignment.