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Title: The multiple roles of small-angle tilt grain boundaries in annihilating radiation damage in SiC

Abstract

Lattice defects generated by radiation damage can diffuse to grain boundaries (GBs) and be annihilated at GBs. However, the precise role of GBs in annihilating the segregated defects remains unclear. Here, we employed multi-scale models to determine how interstitials are annihilated at small-angle tilt GBs (STGBs) in SiC. First of all, we found the pipe diffusion of interstitials in STGBs is slower than bulk diffusion. This is because the increased interatomic distance at dislocation cores raises the migration barrier of interstitial dumbbells. Furthermore, we found both the annihilation of interstitials at jogs and jog nucleation from clusters are diffusion-controlled and can occur under off-stoichiometric interstitial fluxes. Finally, a dislocation line model is developed to predict the role of STGBs in annihilating radiation damage. This model includes defect flux to GBs, pipe diffusion in STGBs, and the interaction of defects with jogs. The model predicts the role of STGBs in annihilating defects depends on the rate of defects segregation to and diffusion along STGBs. STGBs mainly serve as diffusion channel for defects to reach other sinks when defect diffusivity is high at boundaries. As a result, when defect diffusivity is low, most of the defects segregated to STGBs are annihilated bymore » dislocation climb.« less

Authors:
 [1];  [1];  [1]
  1. Univ. of Wisconsin, Madison, WI (United States)
Publication Date:
Research Org.:
Univ. of Wisconsin, Madison, WI (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1347521
Grant/Contract Number:  
FG02-08ER46493
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; atomistic models; materials for devices; materials for energy and catalysis; structural materials

Citation Formats

Jiang, Hao, Wang, Xing, and Szlufarska, Izabela. The multiple roles of small-angle tilt grain boundaries in annihilating radiation damage in SiC. United States: N. p., 2017. Web. doi:10.1038/srep42358.
Jiang, Hao, Wang, Xing, & Szlufarska, Izabela. The multiple roles of small-angle tilt grain boundaries in annihilating radiation damage in SiC. United States. doi:10.1038/srep42358.
Jiang, Hao, Wang, Xing, and Szlufarska, Izabela. Thu . "The multiple roles of small-angle tilt grain boundaries in annihilating radiation damage in SiC". United States. doi:10.1038/srep42358. https://www.osti.gov/servlets/purl/1347521.
@article{osti_1347521,
title = {The multiple roles of small-angle tilt grain boundaries in annihilating radiation damage in SiC},
author = {Jiang, Hao and Wang, Xing and Szlufarska, Izabela},
abstractNote = {Lattice defects generated by radiation damage can diffuse to grain boundaries (GBs) and be annihilated at GBs. However, the precise role of GBs in annihilating the segregated defects remains unclear. Here, we employed multi-scale models to determine how interstitials are annihilated at small-angle tilt GBs (STGBs) in SiC. First of all, we found the pipe diffusion of interstitials in STGBs is slower than bulk diffusion. This is because the increased interatomic distance at dislocation cores raises the migration barrier of interstitial dumbbells. Furthermore, we found both the annihilation of interstitials at jogs and jog nucleation from clusters are diffusion-controlled and can occur under off-stoichiometric interstitial fluxes. Finally, a dislocation line model is developed to predict the role of STGBs in annihilating radiation damage. This model includes defect flux to GBs, pipe diffusion in STGBs, and the interaction of defects with jogs. The model predicts the role of STGBs in annihilating defects depends on the rate of defects segregation to and diffusion along STGBs. STGBs mainly serve as diffusion channel for defects to reach other sinks when defect diffusivity is high at boundaries. As a result, when defect diffusivity is low, most of the defects segregated to STGBs are annihilated by dislocation climb.},
doi = {10.1038/srep42358},
journal = {Scientific Reports},
number = ,
volume = 7,
place = {United States},
year = {Thu Feb 09 00:00:00 EST 2017},
month = {Thu Feb 09 00:00:00 EST 2017}
}

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