G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0405, USA.
Nanoscale. 2013 Dec 21;5(24):12532-41. doi: 10.1039/c3nr04035f.
A unique technique to perform quantitative in situ transmission electron microscopy (TEM) fatigue testing on ultrathin films and nanomaterials is demonstrated. The technique relies on a microelectromechanical system (MEMS) device to actuate a nanospecimen and measure its mechanical response. Compared to previously demonstrated MEMS-based in situ TEM techniques, the technique takes advantage of two identical capacitive sensors on each side of the specimen to measure electronically elongation (with nm resolution) and applied force (with μN resolution). Monotonic and fatigue tests were performed on nanocrystalline gold ultrathin film specimens that were manipulated and fixed onto the MEMS device without the use of a focused ion-beam microscope (and therefore, importantly, without any associated surface damage). The major advantage of the technique is its capability to use TEM imaging solely for high magnification microstructural observations while the MEMS device provides continuous tracking of the material's response, thereby expanding the capabilities of MEMS-based techniques towards more complex in situ TEM nanomechanical tests, such as fatigue tests.
本文展示了一种独特的技术，可对超薄薄膜和纳米材料进行定量原位透射电子显微镜（TEM）疲劳测试。该技术依赖于微机电系统（MEMS）设备来驱动纳米样本并测量其机械响应。与之前展示的基于 MEMS 的原位 TEM 技术相比，该技术利用样本每侧的两个相同的电容传感器来测量电子伸长（具有 nm 分辨率）和施加的力（具有 μN 分辨率）。对纳米晶金超薄薄膜样本进行了单调和疲劳测试，这些样本被操纵并固定在 MEMS 设备上，而无需使用聚焦离子束显微镜（因此，重要的是，没有任何相关的表面损伤）。该技术的主要优势在于，它能够仅使用 TEM 成像进行高倍微观结构观察，而 MEMS 设备则提供对材料响应的连续跟踪，从而将基于 MEMS 的技术的功能扩展到更复杂的原位 TEM 纳米力学测试，例如疲劳测试。
