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Title: Binding Energetics of Substitutional and Interstitial Helium and Di-Helium Defects with Grain Boundary Structure in alpha-Fe

Abstract

he formation/binding energetics and length scales associated with the interaction between He atoms and grain boundaries in BCC alpha-Fe was explored. Ten different low grain boundaries from the <100> and <110> symmetric tilt sigma grain boundary systems were used. In this work, we then calculated formation/binding energies for 1 - 2 He atoms in the substitutional and interstitial sites (HeV, He2V, HeInt, He2Int) at all potential grain boundary sites within 15 °A of the boundary (52826 simulations total). The present results provide detailed information about the interaction energies and length scales of 1-2 He atoms with grain boundaries for the structures examined. A number of interesting new findings emerge from the present study. For instance, the sigma3(112) twin boundary in BCC Fe possesses a much smaller binding energy than other boundaries, which corresponds in long time dynamics simulations to the ability of an interstitial He defect to break away from the boundary in simulations on the order of nanoseconds. Additionally, positive correlations between the calculated formation/binding energies of the He defects (R > 0.9) asserts that the local environment surrounding each site strongly influences the He defect energies and that highly accurate quantum mechanics calculations of lower order defects maymore » be an adequate predictor of higher order defects. Various metrics to quantify or classify the local environment were compared with the He defect binding energies. The present work shows that the binding and formation energies for He defects are important for understanding the physics of He diffusion and trapping by grain boundaries, which can be important for modeling He interactions in polycrystalline steels.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1177317
Report Number(s):
PNNL-SA-100253
AT6020100
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics, 115:033503
Country of Publication:
United States
Language:
English
Subject:
HELIUM; GRAIN BOUNDARIES; IRON; INTERSTITIALS; Helium; grain boundaries; iron; interstitial; substitutional; forma- tion/binding energy

Citation Formats

Tschopp, Mark A., Gao, Fei, Yang, Li, and Solanki, K. N. Binding Energetics of Substitutional and Interstitial Helium and Di-Helium Defects with Grain Boundary Structure in alpha-Fe. United States: N. p., 2014. Web. doi:10.1063/1.4861719.
Tschopp, Mark A., Gao, Fei, Yang, Li, & Solanki, K. N. Binding Energetics of Substitutional and Interstitial Helium and Di-Helium Defects with Grain Boundary Structure in alpha-Fe. United States. doi:10.1063/1.4861719.
Tschopp, Mark A., Gao, Fei, Yang, Li, and Solanki, K. N. Tue . "Binding Energetics of Substitutional and Interstitial Helium and Di-Helium Defects with Grain Boundary Structure in alpha-Fe". United States. doi:10.1063/1.4861719.
@article{osti_1177317,
title = {Binding Energetics of Substitutional and Interstitial Helium and Di-Helium Defects with Grain Boundary Structure in alpha-Fe},
author = {Tschopp, Mark A. and Gao, Fei and Yang, Li and Solanki, K. N.},
abstractNote = {he formation/binding energetics and length scales associated with the interaction between He atoms and grain boundaries in BCC alpha-Fe was explored. Ten different low grain boundaries from the <100> and <110> symmetric tilt sigma grain boundary systems were used. In this work, we then calculated formation/binding energies for 1 - 2 He atoms in the substitutional and interstitial sites (HeV, He2V, HeInt, He2Int) at all potential grain boundary sites within 15 °A of the boundary (52826 simulations total). The present results provide detailed information about the interaction energies and length scales of 1-2 He atoms with grain boundaries for the structures examined. A number of interesting new findings emerge from the present study. For instance, the sigma3(112) twin boundary in BCC Fe possesses a much smaller binding energy than other boundaries, which corresponds in long time dynamics simulations to the ability of an interstitial He defect to break away from the boundary in simulations on the order of nanoseconds. Additionally, positive correlations between the calculated formation/binding energies of the He defects (R > 0.9) asserts that the local environment surrounding each site strongly influences the He defect energies and that highly accurate quantum mechanics calculations of lower order defects may be an adequate predictor of higher order defects. Various metrics to quantify or classify the local environment were compared with the He defect binding energies. The present work shows that the binding and formation energies for He defects are important for understanding the physics of He diffusion and trapping by grain boundaries, which can be important for modeling He interactions in polycrystalline steels.},
doi = {10.1063/1.4861719},
journal = {Journal of Applied Physics, 115:033503},
number = ,
volume = ,
place = {United States},
year = {Tue Jan 21 00:00:00 EST 2014},
month = {Tue Jan 21 00:00:00 EST 2014}
}