In situ studies of amorphization of the GeAl and SiAl systems induced by 1 MeV electron irradiation

X. W. Lin*, David N Seidman, P. R. Okamoto

*Corresponding author for this work

Research output: Contribution to journalArticle

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Abstract

GeAl and SiAl bilayer specimens, and also A1-2.3at.%Ge two-phase alloy specimens, were irradiated in situ with 1 MeV electrons at temperatures in the range 10-190 K in a high voltage electron microscope. The Ge precipitates in the Al2.3at.%Ge alloy disappeared completely at a critical fluence (Φc) of approximately 2.4 × 1023 cm-2 (24 displacements per atom (dpa) in Ge and 14 dpa in Al) for specimens irradiated at 10 or 50 K; this is the same value of Φc at which GeAl bilayers are found to contain an amorphous phase. At 10 K an irradiated GeAl bilayer specimen is found to have an amorphous phase at the interface only when a Ge layer faces the incident electron beam, while for a SiAl bilayer specimen amorphization occurs at the interface independent of the direction of the incident beam with respect to a bilayer. For GeAl bilayer specimens Φc is approximately 2.5 × 1023 cm-2 (25 dpa in Ge and 15 dpa in Al). For SiAl bilayers Φc is approximately 3 × 1023 cm-2 (19 dpa in Si and 18 dpa in Al). The temperature dependence of Φc is also studied for a GeAl bilayer specimen. The value of Φc is a constant for T < ≈160 K, and then it increases rapidly with increasing T; Φc becomes immeasurably large (more than 70 dpa in Ge and more than 43 dpa in Al) at a critical temperature of about 190 K. The temperature dependence of the crystalline to amorphous transition is explained in terms of a recoil-implantation mechanism, coupled with a radiation-enhanced monovacancy diffusion mechanism for Ge atoms in Al, and an athermal contribution to Ge diffusion in Al via an electron-beam stimulated monovacancy migration mechanism.

Original languageEnglish (US)
Pages (from-to)389-400
Number of pages12
JournalJournal of Alloys and Compounds
Volume194
Issue number2
DOIs
StatePublished - May 7 1993

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Electron irradiation
Amorphization
Atoms
Electron beams
Temperature
Theophylline
Precipitates
Electron microscopes
Crystalline materials
Radiation
Electrons
Electric potential

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

Cite this

@article{b89e69c616f946deb050613f8b1153fd,
title = "In situ studies of amorphization of the GeAl and SiAl systems induced by 1 MeV electron irradiation",
abstract = "GeAl and SiAl bilayer specimens, and also A1-2.3at.{\%}Ge two-phase alloy specimens, were irradiated in situ with 1 MeV electrons at temperatures in the range 10-190 K in a high voltage electron microscope. The Ge precipitates in the Al2.3at.{\%}Ge alloy disappeared completely at a critical fluence (Φc) of approximately 2.4 × 1023 cm-2 (24 displacements per atom (dpa) in Ge and 14 dpa in Al) for specimens irradiated at 10 or 50 K; this is the same value of Φc at which GeAl bilayers are found to contain an amorphous phase. At 10 K an irradiated GeAl bilayer specimen is found to have an amorphous phase at the interface only when a Ge layer faces the incident electron beam, while for a SiAl bilayer specimen amorphization occurs at the interface independent of the direction of the incident beam with respect to a bilayer. For GeAl bilayer specimens Φc is approximately 2.5 × 1023 cm-2 (25 dpa in Ge and 15 dpa in Al). For SiAl bilayers Φc is approximately 3 × 1023 cm-2 (19 dpa in Si and 18 dpa in Al). The temperature dependence of Φc is also studied for a GeAl bilayer specimen. The value of Φc is a constant for T < ≈160 K, and then it increases rapidly with increasing T; Φc becomes immeasurably large (more than 70 dpa in Ge and more than 43 dpa in Al) at a critical temperature of about 190 K. The temperature dependence of the crystalline to amorphous transition is explained in terms of a recoil-implantation mechanism, coupled with a radiation-enhanced monovacancy diffusion mechanism for Ge atoms in Al, and an athermal contribution to Ge diffusion in Al via an electron-beam stimulated monovacancy migration mechanism.",
author = "Lin, {X. W.} and Seidman, {David N} and Okamoto, {P. R.}",
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journal = "Journal of Alloys and Compounds",
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}

In situ studies of amorphization of the GeAl and SiAl systems induced by 1 MeV electron irradiation. / Lin, X. W.; Seidman, David N; Okamoto, P. R.

In: Journal of Alloys and Compounds, Vol. 194, No. 2, 07.05.1993, p. 389-400.

Research output: Contribution to journalArticle

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T1 - In situ studies of amorphization of the GeAl and SiAl systems induced by 1 MeV electron irradiation

AU - Lin, X. W.

AU - Seidman, David N

AU - Okamoto, P. R.

PY - 1993/5/7

Y1 - 1993/5/7

N2 - GeAl and SiAl bilayer specimens, and also A1-2.3at.%Ge two-phase alloy specimens, were irradiated in situ with 1 MeV electrons at temperatures in the range 10-190 K in a high voltage electron microscope. The Ge precipitates in the Al2.3at.%Ge alloy disappeared completely at a critical fluence (Φc) of approximately 2.4 × 1023 cm-2 (24 displacements per atom (dpa) in Ge and 14 dpa in Al) for specimens irradiated at 10 or 50 K; this is the same value of Φc at which GeAl bilayers are found to contain an amorphous phase. At 10 K an irradiated GeAl bilayer specimen is found to have an amorphous phase at the interface only when a Ge layer faces the incident electron beam, while for a SiAl bilayer specimen amorphization occurs at the interface independent of the direction of the incident beam with respect to a bilayer. For GeAl bilayer specimens Φc is approximately 2.5 × 1023 cm-2 (25 dpa in Ge and 15 dpa in Al). For SiAl bilayers Φc is approximately 3 × 1023 cm-2 (19 dpa in Si and 18 dpa in Al). The temperature dependence of Φc is also studied for a GeAl bilayer specimen. The value of Φc is a constant for T < ≈160 K, and then it increases rapidly with increasing T; Φc becomes immeasurably large (more than 70 dpa in Ge and more than 43 dpa in Al) at a critical temperature of about 190 K. The temperature dependence of the crystalline to amorphous transition is explained in terms of a recoil-implantation mechanism, coupled with a radiation-enhanced monovacancy diffusion mechanism for Ge atoms in Al, and an athermal contribution to Ge diffusion in Al via an electron-beam stimulated monovacancy migration mechanism.

AB - GeAl and SiAl bilayer specimens, and also A1-2.3at.%Ge two-phase alloy specimens, were irradiated in situ with 1 MeV electrons at temperatures in the range 10-190 K in a high voltage electron microscope. The Ge precipitates in the Al2.3at.%Ge alloy disappeared completely at a critical fluence (Φc) of approximately 2.4 × 1023 cm-2 (24 displacements per atom (dpa) in Ge and 14 dpa in Al) for specimens irradiated at 10 or 50 K; this is the same value of Φc at which GeAl bilayers are found to contain an amorphous phase. At 10 K an irradiated GeAl bilayer specimen is found to have an amorphous phase at the interface only when a Ge layer faces the incident electron beam, while for a SiAl bilayer specimen amorphization occurs at the interface independent of the direction of the incident beam with respect to a bilayer. For GeAl bilayer specimens Φc is approximately 2.5 × 1023 cm-2 (25 dpa in Ge and 15 dpa in Al). For SiAl bilayers Φc is approximately 3 × 1023 cm-2 (19 dpa in Si and 18 dpa in Al). The temperature dependence of Φc is also studied for a GeAl bilayer specimen. The value of Φc is a constant for T < ≈160 K, and then it increases rapidly with increasing T; Φc becomes immeasurably large (more than 70 dpa in Ge and more than 43 dpa in Al) at a critical temperature of about 190 K. The temperature dependence of the crystalline to amorphous transition is explained in terms of a recoil-implantation mechanism, coupled with a radiation-enhanced monovacancy diffusion mechanism for Ge atoms in Al, and an athermal contribution to Ge diffusion in Al via an electron-beam stimulated monovacancy migration mechanism.

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