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Title: Irradiation-induced β to α SiC transformation at low temperature

Abstract

Here, we observed that β-SiC, neutron irradiated to 9 dpa (displacements per atom) at ≈1440 °C, began transforming to α-SiC, with radiation-induced Frank dislocation loops serving as the apparent nucleation sites. 1440 °C is a far lower temperature than usual β → α phase transformations in SiC. SiC is considered for applications in advanced nuclear systems, as well as for electronic or spintronic applications requiring ion irradiation processing. β-SiC, preferred for nuclear applications, is metastable and undergoes a phase transformation at high temperatures (typically 2000 °C and above). Nuclear reactor concepts are not expected to reach the very high temperatures for thermal transformation. However, our results indicate incipient β → α phase transformation, in the form of small (~5–10 nm) pockets of α-SiC forming in the β matrix. In service transformation could degrade structural stability and fuel integrity for SiC-based materials operated in this regime. However, engineering this transformation deliberately using ion irradiation could enable new electronic applications.

Authors:
 [1];  [1];  [2];  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Kyoto Univ., Kyoto (Japan)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Nuclear Science User Facility (NSUF)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1356892
Grant/Contract Number:
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 7; Journal Issue: 1; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ceramics; electronic devices; nuclear fusion and fission

Citation Formats

Parish, Chad M., Koyanagi, Takaaki, Kondo, Sosuke, and Katoh, Yutai. Irradiation-induced β to α SiC transformation at low temperature. United States: N. p., 2017. Web. doi:10.1038/s41598-017-01395-y.
Parish, Chad M., Koyanagi, Takaaki, Kondo, Sosuke, & Katoh, Yutai. Irradiation-induced β to α SiC transformation at low temperature. United States. doi:10.1038/s41598-017-01395-y.
Parish, Chad M., Koyanagi, Takaaki, Kondo, Sosuke, and Katoh, Yutai. Wed . "Irradiation-induced β to α SiC transformation at low temperature". United States. doi:10.1038/s41598-017-01395-y. https://www.osti.gov/servlets/purl/1356892.
@article{osti_1356892,
title = {Irradiation-induced β to α SiC transformation at low temperature},
author = {Parish, Chad M. and Koyanagi, Takaaki and Kondo, Sosuke and Katoh, Yutai},
abstractNote = {Here, we observed that β-SiC, neutron irradiated to 9 dpa (displacements per atom) at ≈1440 °C, began transforming to α-SiC, with radiation-induced Frank dislocation loops serving as the apparent nucleation sites. 1440 °C is a far lower temperature than usual β → α phase transformations in SiC. SiC is considered for applications in advanced nuclear systems, as well as for electronic or spintronic applications requiring ion irradiation processing. β-SiC, preferred for nuclear applications, is metastable and undergoes a phase transformation at high temperatures (typically 2000 °C and above). Nuclear reactor concepts are not expected to reach the very high temperatures for thermal transformation. However, our results indicate incipient β → α phase transformation, in the form of small (~5–10 nm) pockets of α-SiC forming in the β matrix. In service transformation could degrade structural stability and fuel integrity for SiC-based materials operated in this regime. However, engineering this transformation deliberately using ion irradiation could enable new electronic applications.},
doi = {10.1038/s41598-017-01395-y},
journal = {Scientific Reports},
number = 1,
volume = 7,
place = {United States},
year = {Wed Apr 26 00:00:00 EDT 2017},
month = {Wed Apr 26 00:00:00 EDT 2017}
}

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