An elastoplastic phase-field model for the evolution of hydride precipitation in zirconium. Part I: Smooth specimen

An elastoplastic phase-field model was developed to simulate the morphology evolution of hydride precipitation in zirconium bulk material without flaws (considered in this part), and with flaws (considered in Part II). In the present Part I, a theoretical framework based on the phase-field method is described. In addition to long range order parameters used to describe the orientation difference of hydrides and the conserved parameter used to represent the hydrogen concentration, the plastic strains were adopted as new order parameters to describe the plastic deformation around the hydrides. The simulation results showed that the plastic deformation decreases the stress level around hydrides significantly. Moreover, the externally applied stress not only plays an important role in the morphological evolution of hydride precipitation, but also results in tensile stresses inside hydride particles, which may cause crack initiation at the hydrides.