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Title: Chemical effects on He bubble superlattice formation in high entropy alloys

Abstract

The probable formation mechanism of He bubble superlattices relies on long range anisotropic diffusion of self-interstitial atoms (SIAs). Here we study He ion irradiation of pure Ni and two equiatomic concentrated solid-solution alloys (CSAs) of FeNi and FeCrNiCo. It is expected from the significantly reduced diffusion of SIAs in CSAs, including high entropy alloys (HEAs), that long range anisotropic SIA migration cannot be active. We report the formation of a He bubble lattice in pure Ni, and for the first time in FeNi and FeCrNiCo systems under 30 keV He ion irradiation at room temperature. The ion dose and flux required to form a bubble superlattice increase with chemical complexity. Comparing to Ni, SIA clusters change directions more frequently due to anisotropic elementally-biased diffusion from the higher degree of chemical non-homogeneity in CSAs. Nevertheless, anisotropic 1-D diffusion of interstitial defects is possible in these complex alloys over incrementally longer time scales and irradiation doses. The sluggish diffusion, characteristic in CSAs, leads to smaller superlattice parameters and smaller bubble diameters. The chemical biased SIA diffusion and its effects on He evolution revealed here have important implications on understanding and improving radiation tolerance over a wide range of extreme conditions.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1543040
Alternate Identifier(s):
OSTI ID: 1564112
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article: Published Article
Journal Name:
Current Opinion in Solid State and Materials Science
Additional Journal Information:
Journal Name: Current Opinion in Solid State and Materials Science Journal Volume: 23 Journal Issue: 4; Journal ID: ISSN 1359-0286
Publisher:
Elsevier
Country of Publication:
United Kingdom
Language:
English
Subject:
36 MATERIALS SCIENCE; High entropy alloy; Chemical complexity; Irradiation; Helium bubble superlattice; In situ TEM

Citation Formats

Harrison, R. W., Greaves, G., Le, H., Bei, H., Zhang, Y., and Donnelly, S. E. Chemical effects on He bubble superlattice formation in high entropy alloys. United Kingdom: N. p., 2019. Web. doi:10.1016/j.cossms.2019.07.001.
Harrison, R. W., Greaves, G., Le, H., Bei, H., Zhang, Y., & Donnelly, S. E. Chemical effects on He bubble superlattice formation in high entropy alloys. United Kingdom. doi:10.1016/j.cossms.2019.07.001.
Harrison, R. W., Greaves, G., Le, H., Bei, H., Zhang, Y., and Donnelly, S. E. Thu . "Chemical effects on He bubble superlattice formation in high entropy alloys". United Kingdom. doi:10.1016/j.cossms.2019.07.001.
@article{osti_1543040,
title = {Chemical effects on He bubble superlattice formation in high entropy alloys},
author = {Harrison, R. W. and Greaves, G. and Le, H. and Bei, H. and Zhang, Y. and Donnelly, S. E.},
abstractNote = {The probable formation mechanism of He bubble superlattices relies on long range anisotropic diffusion of self-interstitial atoms (SIAs). Here we study He ion irradiation of pure Ni and two equiatomic concentrated solid-solution alloys (CSAs) of FeNi and FeCrNiCo. It is expected from the significantly reduced diffusion of SIAs in CSAs, including high entropy alloys (HEAs), that long range anisotropic SIA migration cannot be active. We report the formation of a He bubble lattice in pure Ni, and for the first time in FeNi and FeCrNiCo systems under 30 keV He ion irradiation at room temperature. The ion dose and flux required to form a bubble superlattice increase with chemical complexity. Comparing to Ni, SIA clusters change directions more frequently due to anisotropic elementally-biased diffusion from the higher degree of chemical non-homogeneity in CSAs. Nevertheless, anisotropic 1-D diffusion of interstitial defects is possible in these complex alloys over incrementally longer time scales and irradiation doses. The sluggish diffusion, characteristic in CSAs, leads to smaller superlattice parameters and smaller bubble diameters. The chemical biased SIA diffusion and its effects on He evolution revealed here have important implications on understanding and improving radiation tolerance over a wide range of extreme conditions.},
doi = {10.1016/j.cossms.2019.07.001},
journal = {Current Opinion in Solid State and Materials Science},
issn = {1359-0286},
number = 4,
volume = 23,
place = {United Kingdom},
year = {2019},
month = {8}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.cossms.2019.07.001

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Cited by: 2 works
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Figures / Tables:

Fig. 1 Fig. 1: SADP of a Ni sample irradiated with 30 keV He ions to a fluence of 1.5 x 1017 ions/cm2 at 298 K showing formation of He bubble superlattice reflections around matrix reflections with schematic of satellite spot refection formation in the SADP (a single set of planes ismore » given for the Ni reflections for diagram simplicity).« less

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