| About this Abstract |
| Meeting |
2023 TMS Annual Meeting & Exhibition
|
| Symposium
|
Phase Transformations and Microstructural Evolution
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| Presentation Title |
Cyclic Degradation of Superelasticity of Fe-Mn-Al-Ni Shape Memory Alloy Studied Complementary In Situ Characterization Techniques |
| Author(s) |
Robert Lehnert, Moritz Müller, Malte Vollmer, Philipp Krooß, Thomas Niendorf, Horst Biermann, Anja Weidner |
| On-Site Speaker (Planned) |
Robert Lehnert |
| Abstract Scope |
The superelasticity of iron-based shape memory alloys is manly determined by microstructural features like grain boundaries, precipitation size or crystal orientation and morphology. Also the interaction of different martensite variants or the interaction of dislocations with the austenite/martensite interface are known to result in a functional degradation. Fe-Mn-Al-Ni and Fe-Ni-Co-Al-Ti single and bicrystals under tensile and compressive loading were used to study functional fatigue with a combination of complementary in situ characterization techniques, e.g. acoustic emission technique (AE), digital image correlation (DIC), high resolution electron backscatter diffraction (HR-EBSD), electron contrast channeling imaging (ECCI) and infrared thermography (IR-TG). The acoustic data showed a decrease in intensity with increasing number of deformation cycles and was interpreted using the information from the in situ observations. In addition, an asymmetry of the acoustic signals during the forward and the backward martensitic transformation could be observed which is related to the dislocation formation. The pinning effect of the dislocations leads to a reduction in the packet density of the retransforming martensite, which results in a lower amplitude of the AE signals indicating the functional degradation. |
| Proceedings Inclusion? |
Planned: |