TEM studies of crystallographic defects in Cu-based shape memory alloys. – (Adriana Condó / Seminar / CEMES-NanoX). – 5/02/2024, 15 H.

Adriana Condó , CNEA de San Carlos de Bariloche, Argentine

Summary :
The shape memory effect and pseudoelastic properties in Cu-based alloys have their origin in a martensitic transformation that is present for a certain composition range. The martensitic transformation involves a crystalline structure change without atomic diffusion, and different crystallographic defects are generated during the transformation. The transformation can be induced by an applyed stress or by a temperature change, and proceeds by the movement of an undistorted habit plane. The condition of an undistorted habit plane implies the presence of stacking faults or twins, which in addition interact with other defects also created during the martensitic transformation. In this presentation, transmission electron microscopy studies of these crystallographic defects will be shown. Their detailed study is required to understand the mechanisms of the martensitic transformation in these alloys. The microstructural characterization of martensitic phases has been a subject of study in our group in Argentina for many years, and now provides the framework of a scientific collaboration with materials research groups in France.