The effect of δ-hydride on the micromechanical deformation of Zircaloy-4 studied by in situ high angular resolution electron backscatter diffraction

Abstract: Zircaloy-4 is used extensively as nuclear fuel cladding materials and hydride embrittlement is a major failure mechanism. To explore the effect of {\delta}-hydride on plastic deformation and performance of Zircaloy-4, in situ high angular resolution electron backscatter diffraction (HR-EBSD) was used to quantify stress and geometrically necessary dislocation (GND) density during bending tests of hydride-free and hydride-containing single crystal Zircaloy-4 microcantilevers. Results suggest that while the stress applied was accommodated by plastic slip in the hydride-free cantilever, the hydride-containing cantilever showed precipitation induced GND pile-up at hydride-matrix interface pre-deformation, and considerable locally increasing GND density under tensile stress upon plastic deformation.