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Title: Transmutation-induced precipitation in tungsten irradiated with a mixed energy neutron spectrum

Abstract

Transmutation-induced precipitation in neutron-irradiated tungsten is an important performance concern for its application as plasma facing material in fusion reactors. In this study, segregation and precipitation of transmutant elements in single crystal and polycrystal tungsten irradiated at 460–1100 °C to 0.02–2.4 displacements per atom (dpa) in the High Flux Isotope Reactor were investigated using transmission electron microscopy. The results indicated that nanoscale W-Re-Os clusters were identified in the low dose regime from 0.02 to 0.44 dpa with irradiation temperature lower than 800 °C while acicular-shape precipitates formed when irradiation dose is higher than 1.5 dpa. A tentative roadmap of the kinetics process of the transmutation-induced precipitation in neutron-irradiated tungsten is presented characterizing the defect features (i.e., W-Re-Os clusters and precipitates) consisting of transmutant elements in tungsten irradiated to various doses. All TEM-visible voids were associated with the acicular-shape precipitates. Voids were formed prior to the formation of acicular-shape precipitates and act as strong trapping sites for mobile species involved in the precipitation together with dislocations. Thermal stability of W-Re-Os clusters was assessed by performing a 2-h anneal at 1200 °C on tungsten irradiated to 0.44 dpa at 705 °C. In conclusion, the kinetics process of transmutant elements and radiation defectsmore » are discussed to reveal the underlying mechanisms controlling the formation of precipitates in tungsten.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1];  [2]; ORCiD logo [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24); USDOE Office of Nuclear Energy (NE)
OSTI Identifier:
1484661
Alternate Identifier(s):
OSTI ID: 1484124
Report Number(s):
LA-UR-18-28278
Journal ID: ISSN 1359-6454
Grant/Contract Number:  
AC05-00OR22725; 89233218CNA000001
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 165; Journal Issue: C; Journal ID: ISSN 1359-6454
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Transmutation; Precipitation; Neutron irradiation; Tungsten; Plasma facing material

Citation Formats

Hu, Xunxiang, Parish, Chad M., Wang, Kun, Koyanagi, Takaaki, Eftink, Benjamin Paul, and Katoh, Yutai. Transmutation-induced precipitation in tungsten irradiated with a mixed energy neutron spectrum. United States: N. p., 2018. Web. doi:10.1016/j.actamat.2018.11.032.
Hu, Xunxiang, Parish, Chad M., Wang, Kun, Koyanagi, Takaaki, Eftink, Benjamin Paul, & Katoh, Yutai. Transmutation-induced precipitation in tungsten irradiated with a mixed energy neutron spectrum. United States. doi:10.1016/j.actamat.2018.11.032.
Hu, Xunxiang, Parish, Chad M., Wang, Kun, Koyanagi, Takaaki, Eftink, Benjamin Paul, and Katoh, Yutai. Wed . "Transmutation-induced precipitation in tungsten irradiated with a mixed energy neutron spectrum". United States. doi:10.1016/j.actamat.2018.11.032. https://www.osti.gov/servlets/purl/1484661.
@article{osti_1484661,
title = {Transmutation-induced precipitation in tungsten irradiated with a mixed energy neutron spectrum},
author = {Hu, Xunxiang and Parish, Chad M. and Wang, Kun and Koyanagi, Takaaki and Eftink, Benjamin Paul and Katoh, Yutai},
abstractNote = {Transmutation-induced precipitation in neutron-irradiated tungsten is an important performance concern for its application as plasma facing material in fusion reactors. In this study, segregation and precipitation of transmutant elements in single crystal and polycrystal tungsten irradiated at 460–1100 °C to 0.02–2.4 displacements per atom (dpa) in the High Flux Isotope Reactor were investigated using transmission electron microscopy. The results indicated that nanoscale W-Re-Os clusters were identified in the low dose regime from 0.02 to 0.44 dpa with irradiation temperature lower than 800 °C while acicular-shape precipitates formed when irradiation dose is higher than 1.5 dpa. A tentative roadmap of the kinetics process of the transmutation-induced precipitation in neutron-irradiated tungsten is presented characterizing the defect features (i.e., W-Re-Os clusters and precipitates) consisting of transmutant elements in tungsten irradiated to various doses. All TEM-visible voids were associated with the acicular-shape precipitates. Voids were formed prior to the formation of acicular-shape precipitates and act as strong trapping sites for mobile species involved in the precipitation together with dislocations. Thermal stability of W-Re-Os clusters was assessed by performing a 2-h anneal at 1200 °C on tungsten irradiated to 0.44 dpa at 705 °C. In conclusion, the kinetics process of transmutant elements and radiation defects are discussed to reveal the underlying mechanisms controlling the formation of precipitates in tungsten.},
doi = {10.1016/j.actamat.2018.11.032},
journal = {Acta Materialia},
number = C,
volume = 165,
place = {United States},
year = {Wed Nov 21 00:00:00 EST 2018},
month = {Wed Nov 21 00:00:00 EST 2018}
}

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