Deformation mechanism of embedded hydride within the polycrystalline zirconium matrix

Abstract

It is widely accepted that the characteristics of hydrides in the Zr-based nuclear fuel cladding are critical factors determining the integrity of the spent fuel. Therefore, to mitigate any harm caused by them, we need to gain a deep understanding of the underlying mechanical behavior involving the precipitated hydrides. Using the molecular dynamics (MD) simulation method, we investigated the deformation mechanisms of embedded hydride in the polycrystalline zirconium matrix under uniaxial tensile loading. The plasticity of hydridized zirconium is controlled by the slip transmission from the metallic matrix into the embedded hydride, for which the considerable stress concentration at the metal-hydride interface needs to precede. The proposed mechanism manifests the size-dependent plasticity in the hydride, where the morphology of embedded hydride plays an important role in allowing the slip transmission through the matrix-hydride interface.