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Title: On the mobility of defect clusters and their effect on microstructure evolution in fcc Ni under irradiation

Abstract

Here, µs-scale molecular dynamics studies of vacancy and interstitial clusters in fcc Ni revealed three- and one- dimensional (3-D and 1-D) modes of the cluster motion. The 1-D mobility of interstitial defects is known to enhance swelling rate. The theoretical analysis performed here suggests two novel mechanism by which the 3-D mobile clusters affect microstructure evolution under irradiation. First, the mobility of vacancy clusters hinders nucleation of stable voids due to recombination with interstitial-type loops and edge dislocations. Second, the capture efficiency of dislocations is higher for 3-D mobile vacancy and interstitial clusters than single defects, with the combined effect depending on relative fractions of clustered vacancies and interstitials produced in cascades. The observed differences in radiation damage of most fcc and bcc metals is attributed to the difference in cascade-produced vacancy defects: immobile SFTs and loops in fcc metals and mobile clusters in bcc metals. In this context, fcc Ni is similar to bcc metals due to its high stacking fault energy.

Authors:
ORCiD logo [1];  [2]; ORCiD logo [3]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Univ. of Michigan, Ann Arbor, MI (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Energy Dissipation to Defect Evolution (EDDE); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1493149
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
Materialia
Additional Journal Information:
Journal Volume: 4; Journal Issue: C; Journal ID: ISSN 2589-1529
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Vacancies; Interstitials; Diffusion; Molecular dynamics; Ni; Irradiation effects

Citation Formats

Osetsky, Yuri N., Barashev, Alexander V., and Zhang, Yanwen. On the mobility of defect clusters and their effect on microstructure evolution in fcc Ni under irradiation. United States: N. p., 2018. Web. doi:10.1016/j.mtla.2018.09.028.
Osetsky, Yuri N., Barashev, Alexander V., & Zhang, Yanwen. On the mobility of defect clusters and their effect on microstructure evolution in fcc Ni under irradiation. United States. https://doi.org/10.1016/j.mtla.2018.09.028
Osetsky, Yuri N., Barashev, Alexander V., and Zhang, Yanwen. Tue . "On the mobility of defect clusters and their effect on microstructure evolution in fcc Ni under irradiation". United States. https://doi.org/10.1016/j.mtla.2018.09.028. https://www.osti.gov/servlets/purl/1493149.
@article{osti_1493149,
title = {On the mobility of defect clusters and their effect on microstructure evolution in fcc Ni under irradiation},
author = {Osetsky, Yuri N. and Barashev, Alexander V. and Zhang, Yanwen},
abstractNote = {Here, µs-scale molecular dynamics studies of vacancy and interstitial clusters in fcc Ni revealed three- and one- dimensional (3-D and 1-D) modes of the cluster motion. The 1-D mobility of interstitial defects is known to enhance swelling rate. The theoretical analysis performed here suggests two novel mechanism by which the 3-D mobile clusters affect microstructure evolution under irradiation. First, the mobility of vacancy clusters hinders nucleation of stable voids due to recombination with interstitial-type loops and edge dislocations. Second, the capture efficiency of dislocations is higher for 3-D mobile vacancy and interstitial clusters than single defects, with the combined effect depending on relative fractions of clustered vacancies and interstitials produced in cascades. The observed differences in radiation damage of most fcc and bcc metals is attributed to the difference in cascade-produced vacancy defects: immobile SFTs and loops in fcc metals and mobile clusters in bcc metals. In this context, fcc Ni is similar to bcc metals due to its high stacking fault energy.},
doi = {10.1016/j.mtla.2018.09.028},
journal = {Materialia},
number = C,
volume = 4,
place = {United States},
year = {2018},
month = {9}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Figures / Tables:

Fig. 1 Fig. 1: Time dependence of atomic square displacements created by migration of a single SIA and two to six SIA clusters at temperatures of 500, 600 and 900K.

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Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.