Source truncation and exhaustion: Insights from quantitative in-situ TEM tensile testing

‚Source truncation and exhaustion: Insights from quantitative in-situ
TEM tensile testing' by D. Kiener and A.M. Minor (http://dx.doi.org/10.1021/nl201890s).

The scientific community was challenged by explaining the uncommon
mechanical properties of microscopic samples, leading to the emergence
of two major schools of thought. One group argued that in miniaturized
samples accordingly small dislocations (the carrier of plastic
deformation) will lead to the extraordinarily strength, while the other
envisioned that only pristine volumes could exhibit such high strength.

We developed a new method that shows that both sides are partly right (http://dx.doi.org/10.1021/nl201890s). The paper can be freely accessed thanks to support from the Austrian Science Fund (FWF).

In detail, we developed a technique for performing quantitative
nano-tensile tests with samples being only 100-200 nm thin. The tests
were performed in situ in a transmission electron microscope, which
allows live imaging of individual crystal defects due to its atomic
resolution. The results show that the loaded material gets stronger once
it contains fewer defects. However, the specimen never got totally
defect free, although it sustained stresses above 2 GPa, which it more
than a hundred times the macroscopic bulk value. We measure an increase
in material strength with a reduction in defect density, but still
observe dislocations as carrier of the plastic deformation.