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Title: Computational and Experimental Studies of the Radiation Response of Gd2Ti2O7 Pyrochlore

Abstract

The structure and property changes in Gd2Ti2O7 (polycrystalline pyrochlore) were examined following irradiation with 1 MeV Kr+, 0.6 MeV Bi+ and 4 MeV Au2+ ions over the temperature range 30-950 K. Gd2Ti2O7 readily amorphizes with a low temperature (30 K) critical dose for amorphization of {approx} 0.15 displacements per atom (dpa). The critical temperature above which amorphization does not occur is about 1190 K. Nano-indentation studies reveal that the structural changes were accompanied by decreases of 15% in the Young's modulus. 1 MeV Kr+ irradiation of amorphous Gd2Ti2O7 at 1065 K resulted in ion-beam-assisted recrystallization. These experimental studies were complemented with molecular dynamics simulations of low energy recoils in Gd2Ti2O7 and Gd2Zr2O7 using a Buckingham type potential. The displacement threshold energy surface in both pyrochlores is highly anisotropic. Displacement energies are higher for all sublattices in the titanate pyrochlore compared to the zirconate. Ti sublattice displacements require energies in excess of 100 eV, and result in multiple displacements and defect clusters. The formation of these clusters might impede dynamic defect recovery and facilitate amorphization.

Authors:
;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
891156
Report Number(s):
PNNL-SA-45177
8208; TRN: US0604903
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Conference
Resource Relation:
Conference: Environmental Issues and Waste Management Technologies in the Ceramic and Nuclear Industries XI, Ceramic Transactions, 176(43-54
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CERAMICS; CRITICAL TEMPERATURE; IRRADIATION; PYROCHLORE; RECRYSTALLIZATION; GADOLINIUM OXIDES; TITANIUM OXIDES; RESPONSE FUNCTIONS; MOLECULAR DYNAMICS METHOD; ATOMIC DISPLACEMENTS; Pyrochlore; radiation response; ion implantation; molecular dynamics; displacement threshold energy; Environmental Molecular Sciences Laboratory

Citation Formats

Devanathan, Ram, and Weber, William J. Computational and Experimental Studies of the Radiation Response of Gd2Ti2O7 Pyrochlore. United States: N. p., 2005. Web.
Devanathan, Ram, & Weber, William J. Computational and Experimental Studies of the Radiation Response of Gd2Ti2O7 Pyrochlore. United States.
Devanathan, Ram, and Weber, William J. 2005. "Computational and Experimental Studies of the Radiation Response of Gd2Ti2O7 Pyrochlore". United States.
@article{osti_891156,
title = {Computational and Experimental Studies of the Radiation Response of Gd2Ti2O7 Pyrochlore},
author = {Devanathan, Ram and Weber, William J},
abstractNote = {The structure and property changes in Gd2Ti2O7 (polycrystalline pyrochlore) were examined following irradiation with 1 MeV Kr+, 0.6 MeV Bi+ and 4 MeV Au2+ ions over the temperature range 30-950 K. Gd2Ti2O7 readily amorphizes with a low temperature (30 K) critical dose for amorphization of {approx} 0.15 displacements per atom (dpa). The critical temperature above which amorphization does not occur is about 1190 K. Nano-indentation studies reveal that the structural changes were accompanied by decreases of 15% in the Young's modulus. 1 MeV Kr+ irradiation of amorphous Gd2Ti2O7 at 1065 K resulted in ion-beam-assisted recrystallization. These experimental studies were complemented with molecular dynamics simulations of low energy recoils in Gd2Ti2O7 and Gd2Zr2O7 using a Buckingham type potential. The displacement threshold energy surface in both pyrochlores is highly anisotropic. Displacement energies are higher for all sublattices in the titanate pyrochlore compared to the zirconate. Ti sublattice displacements require energies in excess of 100 eV, and result in multiple displacements and defect clusters. The formation of these clusters might impede dynamic defect recovery and facilitate amorphization.},
doi = {},
url = {https://www.osti.gov/biblio/891156}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Dec 16 00:00:00 EST 2005},
month = {Fri Dec 16 00:00:00 EST 2005}
}

Conference:
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