Plasticity live: Direct observation nanomechanical testing in the TEM

The transmission electron microscope (TEM) is usually used as a tool to investigate the microstructures of materials after deformation or to reveal the dynamic evolution of materials upon the application of stress when equipped with a qualitative deformation holder. Scanning probe microscopes equipped with a force-displacement transducer are known to provide quantitative mechanical data regarding material deformation. The fundamental mechanical mechanism of materials deformation is usually inferred from the above data. However, the absence of a one-to-one relationship between the microstructure and the mechanical curve makes the inferred mechanism at best a reasonable speculation. By incorporating the advantages of these two kinds of instruments, we have recently developed a novel and unique in situ TEM device, named Picolndenter, which provides an unprecedented ability to accurately measure the force vs. displacement relationship during the deformation of individual nanostructures while simultaneously live-monitoring the microstructure evolution. This presentation will report the current progress in applying our unique in situ TEM device (transducer specifications are 0.4nm RMS noise floor and 5000nm maximum for displacement and 0.1 μN RMS noise floor and 1000μN maximum for load) to mechanical measurement of sub-micron Al grains, nanoparticles, nanowires, and sub-micron pillars. The underlying physical mechanisms that account for the observed novel experimental phenomena will be discussed.