Applications of TEM techniques to materials science

A. M. CONDÓ

Congreso; 15th Interamerican Microscopy Congress; 2019

Presentación invitada como plenaria.In this presentation, applications of transmission electron microscopy techniques will be focused on metallic alloys, and in particular on shape memory alloys. These alloys, also called superelastic alloys, are used for medical devices, damping-seismic devices, and are also current subject of research for new applications in microelectromechanical devices. The mechanical properties of these alloys are related to the internal microstructure which can be characterized in detail by TEM. The presence of microscopic defects in the alloys, like dislocations, stacking faults, antiphase boundaries and precipitates was investigated using diffraction contrast techniques, such as bright field / dark field in two-beam condition, bright field in zone axis orientation, dark field using specific-phase spots. The structure of some defects at the atomic level was studied by High Resolution TEM (HRTEM). By convergent beam electron diffraction (CBED), precise and localized lattice parameters were obtained. Finally, using an energy filter, zero energy-loss diffraction patterns were obtained for the precise measurement of faint reflections to study the atomic degree of order.