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

JOURNAL OF ALLOYS AND COMPOUNDS

卷:661

Article

Wang, Zhiyang^1,2  Steuwer, Axel³  Liu, Nanxi¹  Maimaitiyili, Tuerdi⁴  Avdeev, Maxim⁵  Blomqvist, Jakob⁴  Bjerken, Christina⁴  Curfs, Caroline⁶  Kimpton, Justin A.²  Daniels, John E.¹ 

[1] UNSW Australia, Sch Mat Sci & Engn, Sydney, NSW 2052, Australia

[2] Australian Synchrotron, Clayton, Vic 3168, Australia

[3] Nelson Mandela Metropolitain Univ, ZA-6031 Port Elizabeth, South Africa

[4] Malmo Univ, Mat Sci & Appl Math, S-20506 Skane, Sweden

[5] Australian Nucl Sci & Technol Org, Bragg Inst, Lucas Heights, NSW 2234, Australia

[6] European Synchrotron Radiat Facil, F-38000 Grenoble, France

关键词: Metal hydrides;    Phase transitions;    Neutron diffraction;    Zirconium hydride;    Zirconium;    Nuclear materials;   

DOI  :  10.1016/j.jallcom.2015.11.187

来源: Elsevier

【 摘 要 】

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 alpha-Zr + delta-ZrD -> gamma-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 gamma-hydride formation rather than fast cooling as reported earlier. In contrast to the observation that the delta-hydride present in the system remained at temperatures up to 740 K, the produced gamma phase transformed to delta-hydride in the temperature range of 370 K-559 K, with the transformation completing at approximately 559 K. It is confirmed that the formation of the gamma-hydride was reproducible with slow cooling, and a diffusion-controlled sluggish delta-to gamma-hydride transformation is suggested to be responsible for the favorable development of gamma-hydride during slow cooling. (C) 2015 Elsevier B.V. All rights reserved.

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