Modern transmission electron microscopes (TEMs) provide imaging capabilities at unprecedented magnifications that are many orders of magnitude beyond what can be accomplished with standard optical microscopes. Angstrom or sub-angstrom resolutions can routinely be achieved for imaging down to the atomic scale. Beyond passively imaging the sample, the combination of TEM imaging with in-situ mechanical testing opens the door for the observation of a host of mechanical phenomena.
Bruker’s Hysitron PI 95 TEM PicoIndenter instrument is the first full-fledged depth-sensing indenter capable of direct-observation nanomechanical testing inside a transmission electron microscope. Quantitative load-displacement data is acquired with simultaneous TEM observation of stress induced phenomena such as phase transformations, dislocation bursts, fracture onset, and interfacial failure. Certain test parameters can be determined a priori, such as variations in chemical composition or the presence of preexisting defects in the specimen. In addition to imaging, selected-area diffraction can be used to determine sample orientation and loading direction. The pairing of nanoscale mechanical testing with high resolution TEM imaging gives researchers a powerful tool for investigating deformation mechanisms at their most fundamental level.
