Imaging of transient structures using nanosecond in situ TEM
Imaging of transient structures using nanosecond in situ TEM
复制标题
DOI：
10.1126/science.1161517
复制
发表时间：
2008-09-12
期刊：
影响因子：
56.9
通讯作者：
Campbell, Geoffrey H.
中科院分区：
文献类型：
--
作者：
Kim, Judy S.;LaGrange, Thomas;Campbell, Geoffrey H.
材料的微观结构和性能取决于动态过程，如缺陷运动、成核和生长以及相变。透射电子显微镜（TEM）可以在空间上解决这些纳米级的现象，但缺乏直接观察的时间分辨率。我们使用了光发射电子脉冲探测动态事件的“快照”衍射和成像在15纳秒的分辨率内的动态TEM。利用这种能力，原位观察到反应性纳米层合物的移动反应前沿。时间分辨图像和衍射显示了动态混合、自蔓延反应前沿中的瞬态细胞形态，揭示了冷却过程中的短暂相分离，从而提供了对驱动自蔓延高温合成的机制的见解。
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.