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This content will become publicly available on August 4, 2017

Title: Determination of crystal growth rates during rapid solidification of polycrystalline aluminum by nano-scale spatio-temporal resolution in situ transmission electron microscopy

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 the 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 measurementsmore » 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
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [3]
  1. Univ. of Pittsburgh, Pittsburgh, PA (United States); Swiss Federal Lab. for Materials Science and Technology, Duebendorf (Switzerland)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. Univ. of Pittsburgh, Pittsburgh, PA (United States)
  4. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ecole Polytechnique Federale de Lausanne (Lausanne)
  5. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)l; Integrated Dynamic Electron Solutions, Pleasanton, CA (United States)
  6. Materials Science Division, Physical and Life Science Directorate, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94551, USA
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 0021-8979; JAPIAU
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 120; Journal Issue: 5; Journal ID: ISSN 0021-8979
American Institute of Physics (AIP)
Research Org:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
36 MATERIALS SCIENCE solidification; transmission electron microscopy; liquid thin films; liquid solid interfaces; crystal growth