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Title: Defect production and formation of helium-vacancy clusters due to cascades in alpha-iron

Abstract

Displacement cascades are simulated by molecular dynamics (MD) methods in alpha-Fe containing different concentrations of substitutional He atoms. Primary knock-on atom (PKA) energies, Ep , from 500 eV to 5 keV are considered at the irradiation temperature of 100 K. The concentration of He in Fe varies from 1% to 5%, and the results are compared with simulations performed in pure alpha-Fe. We find that the average number of Frenkel pairs per cascade (NF) at low concentrations of He atoms is nearly the same as that in pure Fe, but NF increases with increasing He concentration. The present studies demonstrate for the first time that small He-vacancy bubbles can be nucleated directly from displacement cascades, even for low temperatures at which the vacancies are not mobile. Furthermore, the production efficiency of He-vacancy clusters increases with increasing He concentration and PKA energy. The mechanisms of He bubble nucleation in displacement cascades are discussed in detail.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
908951
Report Number(s):
PNNL-SA-46874
Journal ID: ISSN 0921-4526; PHYBE3; AT6020100; TRN: US0703735
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Physica B Condensed Matter, 391(1):179-185
Additional Journal Information:
Journal Volume: 391; Journal Issue: 1; Journal ID: ISSN 0921-4526
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; IRON; IRRADIATION; KNOCK-ON; NUCLEATION; VACANCIES; HELIUM; MOLECULAR DYNAMICS METHOD; CONCENTRATION RATIO; Defect production; helium-vacancy clusters; Displacement cascades; Alpha-iron

Citation Formats

Yang, Li, Zu, Xiaotao T, Xiao, H Y, Gao, Fei, Heinisch, Howard L, and Kurtz, Richard J. Defect production and formation of helium-vacancy clusters due to cascades in alpha-iron. United States: N. p., 2007. Web. doi:10.1016/j.physb.2006.09.017.
Yang, Li, Zu, Xiaotao T, Xiao, H Y, Gao, Fei, Heinisch, Howard L, & Kurtz, Richard J. Defect production and formation of helium-vacancy clusters due to cascades in alpha-iron. United States. https://doi.org/10.1016/j.physb.2006.09.017
Yang, Li, Zu, Xiaotao T, Xiao, H Y, Gao, Fei, Heinisch, Howard L, and Kurtz, Richard J. Thu . "Defect production and formation of helium-vacancy clusters due to cascades in alpha-iron". United States. https://doi.org/10.1016/j.physb.2006.09.017.
@article{osti_908951,
title = {Defect production and formation of helium-vacancy clusters due to cascades in alpha-iron},
author = {Yang, Li and Zu, Xiaotao T and Xiao, H Y and Gao, Fei and Heinisch, Howard L and Kurtz, Richard J},
abstractNote = {Displacement cascades are simulated by molecular dynamics (MD) methods in alpha-Fe containing different concentrations of substitutional He atoms. Primary knock-on atom (PKA) energies, Ep , from 500 eV to 5 keV are considered at the irradiation temperature of 100 K. The concentration of He in Fe varies from 1% to 5%, and the results are compared with simulations performed in pure alpha-Fe. We find that the average number of Frenkel pairs per cascade (NF) at low concentrations of He atoms is nearly the same as that in pure Fe, but NF increases with increasing He concentration. The present studies demonstrate for the first time that small He-vacancy bubbles can be nucleated directly from displacement cascades, even for low temperatures at which the vacancies are not mobile. Furthermore, the production efficiency of He-vacancy clusters increases with increasing He concentration and PKA energy. The mechanisms of He bubble nucleation in displacement cascades are discussed in detail.},
doi = {10.1016/j.physb.2006.09.017},
url = {https://www.osti.gov/biblio/908951}, journal = {Physica B Condensed Matter, 391(1):179-185},
issn = {0921-4526},
number = 1,
volume = 391,
place = {United States},
year = {2007},
month = {3}
}