Site specific dependencies of hydrogen concentrations in zirconium hydrides

Zircaloy-4 specimens were H-charged up to 1230 wppmH. Intra-, inter- and trans-granular zirconium hydride precipitates (or ZrH2−x where 1/(2 − x) is the Zr/H molar ratio) were observed throughout the α-Zr matrix. Transmission Electron Microscopy and electron diffraction confirmed that the ZrH2−x precipitates were face-centred cubic structures consistent with the δ-ZrH2−x phase. Electron Energy Loss Spectroscopy analysis of the δ-ZrH2−x precipitates at three different nucleation spots displayed shifts in the plasmon energy loss peaks that can be attributed to local variations of the H content of the δ-ZrH2−x precipitates rather than the presence of different ZrH2−x phases as has previously been assumed.