About this Abstract |
Meeting |
2023 TMS Annual Meeting & Exhibition
|
Symposium
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Neutron and X-ray Scattering in Materials Science
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Presentation Title |
Dynamic Imaging of Twin Formation in NiMnGa Based Magnetic Shape Memory Alloys under Cyclic Magnetic Field. |
Author(s) |
Saurabh Kabra, Anton Tremsin, Winfried Kockelmann |
On-Site Speaker (Planned) |
Saurabh Kabra |
Abstract Scope |
We have used time of flight neutron imaging to study the twin variant populations and twin formation/switching dynamics in a magnetic shape memory alloy, NiMnGa. These crystals produce huge elongation (up to 6%) upon the application of a magnetic field. The large elongation is a result of reorientation of twin-variants due to highly mobile twin boundaries. Time of flight allow us to discriminate neutron wavelengths which in turn gives us contrast between different variants in the single crystal due to differences in orientation. Using in situ magnetic field switching we continuously cycle the twins at a frequency between 1-10 Hz. By synchronizing the neutron detection events to the cyclic phenomenon in the shape memory crystal we have been able to image directly, the fast but repeatable twin switching events and the twin boundary motions. We present both the setup and initial results from our first experiments using this setup. |
Proceedings Inclusion? |
Planned: |
Keywords |
Magnetic Materials, Characterization, Mechanical Properties |