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Title: Rapid solidification growth mode transitions in Al-Si alloys by dynamic transmission electron microscopy

Authors:
; ; ORCiD logo; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1397853
Grant/Contract Number:
FWP SCW0974
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 131; Journal Issue: C; Related Information: CHORUS Timestamp: 2017-10-04 22:24:09; Journal ID: ISSN 1359-6454
Publisher:
Elsevier
Country of Publication:
United States
Language:
English

Citation Formats

Roehling, John D., Coughlin, Daniel R., Gibbs, John W., Baldwin, J. Kevin, Mertens, James C. E., Campbell, Geoffrey H., Clarke, Amy J., and McKeown, Joseph T.. Rapid solidification growth mode transitions in Al-Si alloys by dynamic transmission electron microscopy. United States: N. p., 2017. Web. doi:10.1016/j.actamat.2017.03.061.
Roehling, John D., Coughlin, Daniel R., Gibbs, John W., Baldwin, J. Kevin, Mertens, James C. E., Campbell, Geoffrey H., Clarke, Amy J., & McKeown, Joseph T.. Rapid solidification growth mode transitions in Al-Si alloys by dynamic transmission electron microscopy. United States. doi:10.1016/j.actamat.2017.03.061.
Roehling, John D., Coughlin, Daniel R., Gibbs, John W., Baldwin, J. Kevin, Mertens, James C. E., Campbell, Geoffrey H., Clarke, Amy J., and McKeown, Joseph T.. Thu . "Rapid solidification growth mode transitions in Al-Si alloys by dynamic transmission electron microscopy". United States. doi:10.1016/j.actamat.2017.03.061.
@article{osti_1397853,
title = {Rapid solidification growth mode transitions in Al-Si alloys by dynamic transmission electron microscopy},
author = {Roehling, John D. and Coughlin, Daniel R. and Gibbs, John W. and Baldwin, J. Kevin and Mertens, James C. E. and Campbell, Geoffrey H. and Clarke, Amy J. and McKeown, Joseph T.},
abstractNote = {},
doi = {10.1016/j.actamat.2017.03.061},
journal = {Acta Materialia},
number = C,
volume = 131,
place = {United States},
year = {Thu Jun 01 00:00:00 EDT 2017},
month = {Thu Jun 01 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.actamat.2017.03.061

Citation Metrics:
Cited by: 3works
Citation information provided by
Web of Science

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  • Submicron powders of Al-30.3 at. pct Ge (eutectic), produced by electrohydrodynamic atomization, have been analyzed in a transmission electron microscope operating at 120 kV. Amorphous and complex crystalline structures were observed in the as-atomized condition. By using the electron beam as a local heating source, powders could be either annealed at temperatures below their melting point or melted. Molten powders were quenched at various cooling rates by altering the rate of beam obstruction. Using this technique, nonequilibrium structures were produced including metastable phases and mixed amorphous/crystalline microstructures. These various structures have been related to cooling rates and compared to themore » as-atomized structures. Crystallization of the amorphous regions produced by this technique has also been studied.« less
  • In situ investigations of rapid solidification in polycrystalline Al thin films were conducted using nano-scale spatio-temporal resolution dynamic transmission electron microscopy. Differences in crystal growth rates and asymmetries in melt pool development were observed as the heat extraction geometry was varied by controlling the proximity of the laser-pulse irradiation and the associated induced melt pools to the edge of the transmission electron microscopy support grid, which acts as a large heat sink. Experimental parameters have been established to maximize the reproducibility of the material response to the laser-pulse-related heating and to ensure that observations of the dynamical behavior of themore » metal are free from artifacts, leading to accurate interpretations and quantifiable measurements with improved precision. Interface migration rate measurements revealed solidification velocities that increased consistently from ∼1.3 m s{sup −1} to ∼2.5 m s{sup −1} during the rapid solidification process of the Al thin films. Under the influence of an additional large heat sink, increased crystal growth rates as high as 3.3 m s{sup −1} have been measured. The in situ experiments also provided evidence for development of a partially melted, two-phase region prior to the onset of rapid solidification facilitated crystal growth. Using the experimental observations and associated measurements as benchmarks, finite-element modeling based calculations of the melt pool evolution after pulsed laser irradiation have been performed to obtain estimates of the temperature evolution in the thin films.« less
  • In situ investigations of rapid solidification in polycrystalline Al thin films were conducted using nano-scale spatio-temporal resolution dynamic transmission electron microscopy. Differences in crystal growth rates and asymmetries in melt pool development were observed as the heat extraction geometry was varied by controlling the proximity of the laser-pulse irradiation and the associated induced melt pools to the edge of the transmission electron microscopy support grid, which acts as a large heat sink. Experimental parameters have been established to maximize the reproducibility of the material response to the laser-pulse-related heating and to ensure that observations of the dynamical behavior of themore » metal are free from artifacts, leading to accurate interpretations and quantifiable measurements with improved precision. Interface migration rate measurements revealed solidification velocities that increased consistently from ~1.3 m s –1 to ~2.5 m s –1 during the rapid solidification process of the Al thin films. Under the influence of an additional large heat sink, increased crystal growth rates as high as 3.3 m s –1 have been measured. The in situ experiments also provided evidence for development of a partially melted, two-phase region prior to the onset of rapid solidification facilitated crystal growth. As a result, using the experimental observations and associated measurements as benchmarks, finite-element modeling based calculations of the melt pool evolution after pulsed laser irradiation have been performed to obtain estimates of the temperature evolution in the thin films.« less