|About this Abstract
||2024 TMS Annual Meeting & Exhibition
||Advanced Soft Magnets and Magnetocaloric Materials: An FMD Symposium in Honor of Victorino Franco
||Small-scale mechanical shape-memory behaviour of austenitic NiMnGa
||Adnan Fareed, Julian M. Rosalie, Satyakam Kar, Sebastian Fähler, Robert Maaß
|On-Site Speaker (Planned)
Magnetic shape memory alloys offer a variety of multi-scale physical phenomena that can be exploited in actuation. Here we consider a NiMnGa Heusler alloy that has an austenitic structure at room temperature and investigate its small-scale mechanical response. With a particular interest in functional fatigue and potential dissipative processes, cyclic mechanical switching between the austenitic and martensitic phases is conducted with up to one million cycles in the pseudo-elastic range. We find that micron sized NiMnGa crystals essentially show no reduction in strain recovery as a function of cycling loading. This remains true for samples that purposely have been plastically pre-deformed, indicating a remarkable robustness against functional fatigue. Transmission electron microscopy complements our small-scale mechanical study. We discuss our findings in light of the microstructural evolution due to cyclic loading, and in comparison, to the material’s bulk behaviour.
||Magnetic Materials, Mechanical Properties, Phase Transformations