A microstructure-based modeling of delayed hydride cracking in Zr-2.5Nb pressure tube material

In this work, a microstructurally sensitive computational model is developed to simulate delayed hydride cracking (DHC) in Zr-2.5Nb alloy. The model is validated by comparing threshold stress intensity factor (KIH) predictions available in the literature. The anisotropy of Zr-2.5Nb is considered through microstructures containing grains and grain boundaries with different ori-entations and strengths at the mesoscale. A physically consistent damage model with evolving characteristics based on hydride formation is employed to simulate DHC. Results show that the grain anisotropy and grain boundary strength significantly affect the DHC, which may not be generally noticed in the traditional models.