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Title: Irradiation-enhanced second-phase precipitation in Zr-Fe nanocrystalline thin films.

Abstract

In situ observations in a transmission electron microscope (TEM) were used to study ion-beam enhancement of second-phase precipitation in Zr-Fe nanocrystalline thin films. The free-standing films were prepared by co-sputter deposition with an Fe content of 1.2 at%. TEM diffraction analysis showed that only the hcp Zr crystal structure was present in the as-deposited films. No second phases were detected, although Rutherford Backscattering Spectroscopy (RBS) confirmed a Fe content beyond the solubility limit of Fe in Zr (of the order of ppm). This means the thin films were Zr solid solutions supersaturated with Fe. Heat treatment in the absence of irradiation was observed to cause precipitation of the Zr2Fe intermetallic phase, but only above 673 K. The same second-phase precipitation can occur at lower temperatures in the presence of ion irradiation. Samples were irradiated in-situ at the Intermediate Voltage Electron Microscope (IVEM) at Argonne National Laboratory with Kr ions to fluences in excess of 1016 ion/cm2, at temperatures ranging from 50 to 573 K. Second phase precipitation was detected by electron diffraction patterns and by dark field imaging comparing regions exposed to the beam with regions protected from the beam by the TEM support grid. Precipitation of Zr2Fe intermetallic phasemore » was observed at all irradiating temperatures above room temperature. In the bulk, this phase is thermodynamically metastable in the range of temperatures investigated (relative to the orthorhombic Zr3Fe intermetallic phase). The kinetics of the irradiation-enhanced second-phase precipitation was followed by recording the diffraction patterns at regular intervals. The dose to precipitation was found to decrease with increasing irradiation temperature.« less

Authors:
; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
963624
Report Number(s):
ANL/MSD/CP-117982
TRN: US200918%%38
DOE Contract Number:  
DE-AC02-06CH11357
Resource Type:
Conference
Resource Relation:
Conference: 2005 Fall Meeting of the Materials Research Society; Nov. 29, 2005 - Dec. 5, 2005; Boston, MA
Country of Publication:
United States
Language:
ENGLISH
Subject:
36 MATERIALS SCIENCE; ANL; CRYSTAL STRUCTURE; DEPOSITION; DIFFRACTION; ELECTRON DIFFRACTION; ELECTRON MICROSCOPES; HEAT TREATMENTS; IRRADIATION; KINETICS; PRECIPITATION; RUTHERFORD BACKSCATTERING SPECTROSCOPY; SOLID SOLUTIONS; SOLUBILITY; THIN FILMS

Citation Formats

Kaoumi, D, Motta, A T, Birtcher, R C, Materials Science Division, and Pennsylvania State Univ. Irradiation-enhanced second-phase precipitation in Zr-Fe nanocrystalline thin films.. United States: N. p., 2005. Web.
Kaoumi, D, Motta, A T, Birtcher, R C, Materials Science Division, & Pennsylvania State Univ. Irradiation-enhanced second-phase precipitation in Zr-Fe nanocrystalline thin films.. United States.
Kaoumi, D, Motta, A T, Birtcher, R C, Materials Science Division, and Pennsylvania State Univ. 2005. "Irradiation-enhanced second-phase precipitation in Zr-Fe nanocrystalline thin films.". United States.
@article{osti_963624,
title = {Irradiation-enhanced second-phase precipitation in Zr-Fe nanocrystalline thin films.},
author = {Kaoumi, D and Motta, A T and Birtcher, R C and Materials Science Division and Pennsylvania State Univ.},
abstractNote = {In situ observations in a transmission electron microscope (TEM) were used to study ion-beam enhancement of second-phase precipitation in Zr-Fe nanocrystalline thin films. The free-standing films were prepared by co-sputter deposition with an Fe content of 1.2 at%. TEM diffraction analysis showed that only the hcp Zr crystal structure was present in the as-deposited films. No second phases were detected, although Rutherford Backscattering Spectroscopy (RBS) confirmed a Fe content beyond the solubility limit of Fe in Zr (of the order of ppm). This means the thin films were Zr solid solutions supersaturated with Fe. Heat treatment in the absence of irradiation was observed to cause precipitation of the Zr2Fe intermetallic phase, but only above 673 K. The same second-phase precipitation can occur at lower temperatures in the presence of ion irradiation. Samples were irradiated in-situ at the Intermediate Voltage Electron Microscope (IVEM) at Argonne National Laboratory with Kr ions to fluences in excess of 1016 ion/cm2, at temperatures ranging from 50 to 573 K. Second phase precipitation was detected by electron diffraction patterns and by dark field imaging comparing regions exposed to the beam with regions protected from the beam by the TEM support grid. Precipitation of Zr2Fe intermetallic phase was observed at all irradiating temperatures above room temperature. In the bulk, this phase is thermodynamically metastable in the range of temperatures investigated (relative to the orthorhombic Zr3Fe intermetallic phase). The kinetics of the irradiation-enhanced second-phase precipitation was followed by recording the diffraction patterns at regular intervals. The dose to precipitation was found to decrease with increasing irradiation temperature.},
doi = {},
url = {https://www.osti.gov/biblio/963624}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2005},
month = {1}
}

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