Regensburg 2010 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

MA: Fachverband Magnetismus

MA 8: Magnetic Shape Memory Alloys

MA 8.13: Vortrag

Montag, 22. März 2010, 18:30–18:45, H22

Training effects of polycrystalline Ni50Mn29Ga21 magnetic shape memory alloy — •Claudia Hürrich, Martin Pötschke, Stefan Roth, Bernd Rellinghaus, and Ludwig Schultz — IFW Dresden, Institute for Metallic Materials, P. O. Box 270116, 01069 Dresden, Germany

The alloy Ni-Mn-Ga arose great interest for its application as a magnetic shape memory material. This effect is caused by reorientation of twin variants by an external magnetic field. So far most of the experiments were concentrated on single crystals. But, this effect can also be realised in polycrystals which can be prepared much more efficiently. Here, polycrystalline samples were prepared by directional solidification with a <100> fibre texture of the high temperature cubic phase parallel to the heat flow. Afterwards a heat treatment was applied for chemical homogenization and stress relaxation in the austenitic state. Then the samples were heated up to the austenitic state and cooled down under load. The microstructure was analysed by Electron Back Scatter Diffraction (EBSD) before and after that treatment. Mechanical training in three directions was tracked by recording stress-strain curves. With increasing the number of training cycles the strain also increases. This work is supported by DFG within SPP 1239.