A microstructure-based modeling approach to predict the mechanical properties of Zr alloy with hydride precipitates

In nuclear reactors, hydrides can form in fuel cladding due to hydrogen absorption in Zircaloy and cause embrittlement. This work presents a microstructure-based finite element model to predict the stress-strain response of Zircaloy containing hydrides. Microstructural details extracted from scanning electron microscopy (SEM) images were used to generate heterogeneous microstructures including the morphology and spatial distribution of hydrides. The constitutive material model for Zircaloy in this study is based on crystal plasticity theory which considers the hexagonal close-packed (HCP) atomic structure of Zircaloy material. The hydrides were modeled as brittle material along with a damage model. Hydride formation inside the Zircaloy matrix results in residual stress. This phenomenon is also captured in this model. A parametric study has been conducted to understand the effect of volume fraction, orientation, and lamellae width of the hydride phase on the mechanical properties of the overall material and the findings were validated against experimental results from the literature.

Automated summary

This study presents a microstructure-based finite element model to predict the stress-strain response of Zircaloy containing hydrides, considering the effect of hydride formation on mechanical properties. Parametric study and experimental validation show that the volume fraction, orientation, and lamellae width of the hydride phase significantly influence the overall material properties.