Observations of temperature stability of γ-zirconium hydride by high-resolution neutron powder diffraction

Summary, in English

The phase evolution in a zirconium–50 deuterium (Zr–50D, at.%) alloy system during thermal cycling has been investigated using in situ high-resolution neutron powder diffraction. The results showed that the peritectoid reaction α-Zr + δ-ZrD → γ-ZrD previously suggested to occur at high temperatures does not take place in the system. Slow cooling, from high temperatures (≥520 K) to room temperature at a rate of 5 K min–1, promoted the γ-hydride formation rather than fast cooling as reported earlier. In contrast to the observation that the δ-hydride present in the system remained at temperatures up to 740 K, the produced γ phase transformed to δ-hydride in the temperature range of 370 K to 559 K, with the transformation completing at approximately 559 K. It is confirmed that the formation of the γ-hydride was reproducible with slow cooling, and a diffusion-controlled sluggish δ-to γ-hydride transformation is suggested to be responsible for the favorable development of γ-hydride during slow cooling.

• Author: Zhiyang Wang; Axel Steuwer; Nanxi Liu; Tuerdi Maimaitiyili; Maxim Avdeev; Jakob Blomqvist; Christina Bjerkén; Caroline Curfs; Justin A. Kimpton; John E. Daniels
• Publishing year: 2015
• Language: English
• Pages: 55-61
• Publication/Series: Journal of Alloys and Compounds
• Volume: 661
• Links: http://dx.doi.org/10.1016/j.jallcom.2015.11.187
• Document type: Journal article
• Publisher: Elsevier
• Topic: Materials Engineering
• Keywords: Metal hydrides; Phase transitions; Neutron diffraction; Zirconium hydride; Zirconium; Nuclear materials
• Status: Published
• ISBN/ISSN/Other: ISSN: 0925-8388