The need to understand fast, complex physical phenomena through direct in situ observation has spurred the development of high-time-resolution transmission electron microscopy (TEM). Two complementary approaches have emerged: the single-shot and stroboscopic techniques. Single-shot TEM has advanced through the development of dynamic transmission electron microscopy (DTEM) and, more recently, by the advent of movie-mode DTEM, which enables high-frame-rate in situ TEM experimentation by capturing nanosecond-scale sequences of images or diffraction patterns. Previous DTEM studies produced only single snapshots of fast material processes. Movie-mode DTEM provides the ability to track the creation, motion, and interaction of individual defects, phase fronts, and chemical reaction fronts, providing invaluable information on the chemical, microstructural, and atomic-level features that govern rapid material processes. This article discusses movie-mode DTEM technology, its application in the study of reaction dynamics in Ti–B-based reactive nanolaminates, and future instrumentation.

Using a spherical aberration (Cs)-corrected scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS), we investigated a 6° low-angle [001] tilt grain boundary in SrTiO3. The enhanced spatial resolution of the aberration corrector leads to the observation of a number of structural variations in the edge dislocations along the grain boundary that neither resemble the standard edge dislocations nor partial dislocations for SrTiO3. Although there appear to be many variants in the structure that can be interpreted as compositional effects, three main classes of core structure are found to be prominent. From EELS analysis, these classifications seem to be related to Sr deficiencies, with the final variety of the cores being consistent with an embedded TiOx rocksalt-like structure.