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Title: A Transmission Electron Microscopy study of the neutron-irradiation response of Ti-based MAX phases at high temperatures

Abstract

Mn+1AXn phases, or simply MAX phases, are unique nanolayered materials that have been attracting the attention of the nuclear materials community worldwide due to the recent reports of superior radiation resistance compared to conventional ceramics. However, the knowledge and understanding of their response to neutron irradiation is fairly limited, in particular at high temperatures where MAX phases are expected to have high thermodynamic phase stability. In this paper, a complete and extensive study of neutron-irradiation effects at high temperatures on Ti-based MAX phases is presented. The MAX phases Ti3SiC2 and Ti2AlC were irradiated at 1273 K in the High-Flux Isotope Reactor located at the Oak Ridge National Laboratory up to 10 displacement per atom (dpa). Post-irradiation characterisation was performed within a Transmission Electron Microscope on both irradiated and pristine samples. Upon increasing the dose from 2 to 10 dpa, the areal density of black-spots in the Ti2AlC was observed to significantly increase while in the Ti3SiC2, disordered dislocation networks were observed. Regarding the Ti3SiC2, black-spot damage was observed to be concentrated within secondary phases, but absent in the matrix. Dislocation lines and loops were observed at both 2 and 10 dpa. The dislocation loops were identified to be of amore » type. At 2 dpa, stacking faults were observed in both materials, but were absent at 10 dpa. Cavities have also been observed, although no relationship with between size and dose was obtained. Finally, at 10 dpa, both MAX phases exhibited evidences of phase decomposition and irradiation-induced segregation. The presented results shed light on a very complex chain of radiation-induced defects in neutron-induced microstructures in both materials at high temperatures, and provide information that will enable better design of more radiation tolerant materials in the future.« less

Authors:
ORCiD logo; ORCiD logo; ; ORCiD logo
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
OSTI Identifier:
1505870
Alternate Identifier(s):
OSTI ID: 1558548
Grant/Contract Number:  
AC05-06OR23100; AC05-00OR22725
Resource Type:
Published Article
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Name: Acta Materialia Journal Volume: 169 Journal Issue: C; Journal ID: ISSN 1359-6454
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; MAX phases; Neutron irradiation; Ti3SiC2; Ti2AlC; Transmission Electron Microscopy (TEM)

Citation Formats

Tunes, Matheus A., Harrison, Robert W., Donnelly, Stephen E., and Edmondson, Philip D. A Transmission Electron Microscopy study of the neutron-irradiation response of Ti-based MAX phases at high temperatures. United States: N. p., 2019. Web. doi:10.1016/j.actamat.2019.02.046.
Tunes, Matheus A., Harrison, Robert W., Donnelly, Stephen E., & Edmondson, Philip D. A Transmission Electron Microscopy study of the neutron-irradiation response of Ti-based MAX phases at high temperatures. United States. doi:10.1016/j.actamat.2019.02.046.
Tunes, Matheus A., Harrison, Robert W., Donnelly, Stephen E., and Edmondson, Philip D. Wed . "A Transmission Electron Microscopy study of the neutron-irradiation response of Ti-based MAX phases at high temperatures". United States. doi:10.1016/j.actamat.2019.02.046.
@article{osti_1505870,
title = {A Transmission Electron Microscopy study of the neutron-irradiation response of Ti-based MAX phases at high temperatures},
author = {Tunes, Matheus A. and Harrison, Robert W. and Donnelly, Stephen E. and Edmondson, Philip D.},
abstractNote = {Mn+1AXn phases, or simply MAX phases, are unique nanolayered materials that have been attracting the attention of the nuclear materials community worldwide due to the recent reports of superior radiation resistance compared to conventional ceramics. However, the knowledge and understanding of their response to neutron irradiation is fairly limited, in particular at high temperatures where MAX phases are expected to have high thermodynamic phase stability. In this paper, a complete and extensive study of neutron-irradiation effects at high temperatures on Ti-based MAX phases is presented. The MAX phases Ti3SiC2 and Ti2AlC were irradiated at 1273 K in the High-Flux Isotope Reactor located at the Oak Ridge National Laboratory up to 10 displacement per atom (dpa). Post-irradiation characterisation was performed within a Transmission Electron Microscope on both irradiated and pristine samples. Upon increasing the dose from 2 to 10 dpa, the areal density of black-spots in the Ti2AlC was observed to significantly increase while in the Ti3SiC2, disordered dislocation networks were observed. Regarding the Ti3SiC2, black-spot damage was observed to be concentrated within secondary phases, but absent in the matrix. Dislocation lines and loops were observed at both 2 and 10 dpa. The dislocation loops were identified to be of a type. At 2 dpa, stacking faults were observed in both materials, but were absent at 10 dpa. Cavities have also been observed, although no relationship with between size and dose was obtained. Finally, at 10 dpa, both MAX phases exhibited evidences of phase decomposition and irradiation-induced segregation. The presented results shed light on a very complex chain of radiation-induced defects in neutron-induced microstructures in both materials at high temperatures, and provide information that will enable better design of more radiation tolerant materials in the future.},
doi = {10.1016/j.actamat.2019.02.046},
journal = {Acta Materialia},
number = C,
volume = 169,
place = {United States},
year = {2019},
month = {5}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
DOI: 10.1016/j.actamat.2019.02.046

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Cited by: 4 works
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