| Abstract Scope |
Plastic deformation and fracture of crystals are originated from generation of lattice defect such as dislocations, twins and cracks under a mechanical stress. It is important to understand their behavior upon loading. In situ transmission electron microscopy (TEM) mechanical testing is a powerful technique to observe mechanical response of lattice defects. In this study, we investigate the mechanical responses of oxide crystals from nano to atomic scale. Firstly, the behavior of deformation twinning in sapphire (α-Al2O3) is discussed. In situ nanoindentation and scanning TEM revealed that the twin propagation occurs by glide of step structures on the matrix/twin interfaces. Secondly, we introduce our custom-made loading device fabricated by micro electro mechanical system (MEMS) technique. This device has a good stability and loading resolution, and thus it is capable of performing atomic-resolution in situ TEM mechanical testing. Some results of in situ observations obtained using the loading device will be shown. |