Imaging of Transient Structures Using Nanosecond in Situ TEM
Judy S. Kim,1,2*
Thomas LaGrange,1
Bryan W. Reed,1
Mitra L. Taheri,1
Michael R. Armstrong,1
Wayne E. King,1
Nigel D. Browning,1,2
Geoffrey H. Campbell1
The microstructure and properties of a material depend on dynamic
processes such as defect motion, nucleation and growth, and
phase transitions. Transmission electron microscopy (TEM) can
spatially resolve these nanoscale phenomena but lacks the time
resolution for direct observation. We used a photoemitted electron
pulse to probe dynamic events with "snapshot" diffraction and
imaging at 15-nanosecond resolution inside of a dynamic TEM.
With the use of this capability, the moving reaction front of
reactive nanolaminates is observed in situ. Time-resolved images
and diffraction show a transient cellular morphology in a dynamically
mixing, self-propagating reaction front, revealing brief phase
separation during cooling, and thus provide insights into the
mechanisms driving the self-propagating high-temperature synthesis.
2 Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616, USA.
* To whom correspondence should be addressed. E-mail: kim46{at}llnl.gov
