Micro- and Nanomechanics

We encounter miniaturized objects in our daily life, as they are present, for example, in integrated circuits, cell phones, flexible displays, or various miniaturized sensors or actuators, in the form of thin films, conducting wires, or more complicated structures. And we are used to the fact that these objects get ever smaller and cheaper.

Size comparison: Human hair vs. miniaturized tensile samples

However, once material dimensions are reduced to the micron- and sub-micron range, material properties are subject to significant change. Thus, mechanical properties start to depend on the sample size. Moreover, due to the large surface-to-volume ratio of small structures, deformation mechanisms are subject to change.

Microindenter in the SEM To unveil the basic mechanisms governing deformation in small dimensions, we use advanced techniques to structure such small samples and perform quantitative miniaturized experiments directly inside electron microscopes like the SEM or TEM . The direct observation of the sample deformation in combination with the mechanical data allows for a comprehensive understanding of the governing processes.

 

Miniaturized in situ SEM loading experiments Experiments range from simple uniaxial compression or tensile tests to bending, fatigue and fracture experiments on a broad range of materials, ranging from single crystals over thin films and layered systems to nanocomposites or nanoporous materials.

 

 

 

In situ deformation in the TEM

Moving into the TEM for mechanical testing, direct correlation between the mechanical behavior of nanostructured materials and the dynamics of individual crystal defects can be established.

 

D. Kiener, P. Hosemann, S. A. Maloy, and A. M. Minor: In situ nanocompression testing of irradiated copper. Nat. Mater. 10, 608 (2011)
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D. Kiener, and A. M. Minor: Source Truncation and Exhaustion: Insights from Quantitative in situ TEM Tensile Testing. Nano Lett. 11, 3816 (2011)
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D. Kiener, P. Kaufmann, and A. M. Minor: Strength, Hardening, and Failure Observed by In Situ TEM Tensile Testing. Adv. Eng. Mater. 14, 960 (2012)
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