In nano world,
even mechanical properties – something you think is mundane
– can be quite exotic and different from the bulk
counterpart. Carbon nanotubes, stronger than steel, is a good example.
State-of-art wind turbines and turbo engine blades employ
nanotechnology for stronger, lighter, and longer life components. Thus,
studying the mechanical properties of nanomaterials is important. What
would be even more exciting is to watch how the nanomaterials respond
under mechanical stresses in real time. How would defects be created
and propagated when you squash or stretch a nanotube, for example?
Would the mechanical response change drastically if the number of atoms
involved is limited to only a few hundred atoms? Using in situ
nanoindentation holder in TEM, our group is investigating how a
nanostructure would deform under a mechanical stress induced by a
diamond tip in situ.
– nanoindentation of gold nanoparticles
Dark field TEM
images of a gold nanoparticle, before and after indented with a diamond
tip. Twinning boundaries and other defects can be easily imaged in dark
field where only a few diffracted spots are selected to form an image.