Quantifying irradiation defects in zirconium alloys: a comparison between transmission electron microscopy and whole-pattern diffraction line-profile analysis

Levente Balogh, Fei Long, Zhongwen Yao, Michael Preuss, Mark R. Daymond

Research output: Chapter in Book/Report/Conference proceedingConference PaperOther

Abstract

Irradiation-induced dislocations significantly affect the mechanical properties of zirconium alloys, altering slip and influencing creep and growth. Thus, the quantitative characterization of irradiation defects as a function of fluence, cold work, and/or thermal treatments is important for models that attempt to predict their impact on properties. Whole-pattern diffraction line-profile analysis (DLPA) is a well-established modern tool for microstructure characterization based on first-principle physical models for dislocation density measurements in plastically deformed materials. However, applying these DLPA methods directly to irradiated materials yields higher than expected dislocation density values compared with historical transmission electron microscopy (TEM) measurements and past line-broadening analysis studies calibrated to TEM observations. In an effort to understand these differences, a new microstructural model was developed for DLPA to specifically address dislocation structures consisting of elliptical 〈a〉- and 〈c〉-component loops. To compare the refined DLPA method with TEM measurements, high-resolution neutron diffraction patterns on nonirradiated and irradiated Zr-2.5Nb samples were collected with the Neutron Powder Diffractometer instrument at the Los Alamos Neutron Science Center and were evaluated. High-resolution TEM measurements were performed at the Reactor Materials Testing Laboratory, Queen's University, for comparison with the DLPA results. The capabilities and inherent uncertainties of both the refined DLPA and TEM methods are compared and discussed in detail. We show that the differences between the density values provided by DLPA and TEM are inherent to the methods and can be reconciled with the interpretation of the data.

Original languageEnglish
Title of host publicationZirconium in the Nuclear Industry
Subtitle of host publication18th International Symposium
EditorsRobert J. Comstock, Arthur T. Motta
PublisherASTM International
Pages691-724
Number of pages34
ISBN (Electronic)9780803176416
DOIs
Publication statusPublished - 2018
Externally publishedYes
EventInternational Symposium on Zirconium in the Nuclear Industry 2016 - Hilton Head, United States of America
Duration: 15 May 201619 May 2016
Conference number: 18th
https://www.astm.org/DIGITAL_LIBRARY/STP/SOURCE_PAGES/STP1597.htm

Publication series

NameASTM Special Technical Publication
VolumeSTP 1597
ISSN (Print)0066-0558

Conference

ConferenceInternational Symposium on Zirconium in the Nuclear Industry 2016
CountryUnited States of America
CityHilton Head
Period15/05/1619/05/16
Internet address

Keywords

  • Dislocation loops
  • Irradiation defects
  • TEM
  • X-ray diffraction

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