Microstructural studies of shape memory alloys by transmission electron microscopy

A. M. CONDÓ

Encuentro; XV Reunión Anual de la Asociación Argentina de Cristalografía (AACR 2019).; 2019

Presentación invitada semi-plenaria.In this presentation, applications of transmission electron microscopy (TEM) techniques will be focused on shape memory alloys, also called superelastic alloys. These alloys are used for medical devices and for actuators requiring large density of work in reduced environments. In particular, they are current subject of research for new applications in microelectro-mechanical devices. Their mechanical properties are related to the internal microstructure which can be characterized in detail by TEM. Applying the convergent beam electron diffraction (CBED) technique, precise and localized lattice parameters were obtained. 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. Finally, the presence of defects in the alloys, like dislocations and stacking faults was investigated using diffraction contrast techniques. The structure of the defects at the atomic level was studied by high resolution TEM (HRTEM).