Nanocrystal research points to better MEMS
Scientists at Risø DTU claim to have shown that materials to produce micro-and nanocomponents react very differently depending on crystal size.
The team reckons this research can be used to develop technologies for micro-electro-mechanical systems such as digital microphones in mobile phones, miniature pressure sensors in water pumps and acceleration sensors in airbags.
Using transmission electron microscopy (TEM), Risø DTU has looked into what happens when you deform nanosized titanium crystals. At this scale the size of the titanium crystals determines the behaviour of the metal during mechanical treatment. Titanium crystals of a certain size are deformed in a way that each atom is systematically displaced in proportion to the neighbouring atoms, which results in a macroscopic deformation. This process is called ‘deformation twinning’.
When the titanium crystals become smaller, they are much more difficult to deform. However, this only applies to a certain lower limit. When titanium crystals become smaller than 1µm, they are deformed in the same way as very large crystals. This kind of deformation is called ‘dislocation plasticity’. The discovery has significance for how to produce nanocomponents of metal and ceramics in order to obtain the desired properties in a final component.
With support from the Danish Council for Independent Research | the Danish Research Council for Nature and Universe (FNU), Risø National Laboratory for Sustainable Energy, DTU has acquired new, advanced equipment to study nanocrystals of metal while they are being deformed in an electron microscope.