The preparation of Zr-deuteride and phase stability studies of the Zr-D system

Deuteride phases in the zirconium-deuterium system in the temperature range 25-286 degrees C have been studied in-situ by high resolution neutron diffraction. The study primarily focused on observations of delta ->gamma transformation at 180 degrees C, and the peritectoid reaction alpha + delta gamma at 255 degrees C in commetcial grade Zr powder that was deuterated to a deuterium/Zr ratio of one to one. A detailed description of the zirconium deuteride preparation route by high temperature gas loading is also described. The lattice parameters of alpha-Zr, delta-ZrDx and epsilon-ZrDx were determined by whole pattern crystal structure analysis, using Rietveld and Pawley refinements, and are in good agreement with values reported in the literature. The controversial gamma-hydride phase was observed both in-situ and ex-situ in deuterated Zr powder after a heat treatment at 286 degrees C and slow cooling. (C) 2017 Elsevier B.V. All rights reserved