Regensburg 2007 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
MA: Fachverband Magnetismus
MA 17: Magnetic Shape Memory Alloys
MA 17.9: Vortrag
Mittwoch, 28. März 2007, 17:15–17:30, H10
Stress-Induced Twin Boundary Motion in NiMnGa-Polymer-Composites — •Nils Scheerbaum1, Dietrich Hinz1, Jian Liu1, Oliver Gutfleisch1, Werner Skrotzki2, and Ludwig Schultz1 — 1IFW Dresden, Institut für Metallische Werkstoffe, P.O. Box 270116, D-01171 Dresden, Germany — 2Technische Universität Dresden, Institut für Strukturphysik, D-01062 Dresden, Germany
Composites were prepared by embedding magnetic shape memory (MSM) particles in a polyester matrix. Single-crystalline MSM particles were obtained by mortar grinding of melt-extracted and subsequently annealed Ni50.9Mn27.1Ga22.0 (at.%) fibres. The crystal structure of the martensite is tetragonal (5M) and of uniaxial magneto-crystalline anisotropy with c being the short and easy magnetisation axis. Previous magnetic characterisation of these composites showed indirect evidence for stress-induced twin boundary motion in the MSM particles, as the compressed composite becomes easier to magnetise in the direction of compression [1]. Therefore, the texture of the embedded Ni-Mn-Ga particles is investigated before and after compression by means of synchrotron radiation. In the initial state, the MSM particles have a random texture, i.e. there is no preferred orientation of the c-axis. After a 30% compression of the composite, the MSM particles have a [004]-fibre texture in direction of compression [2]. This confirms stress-induced twin boundary motion.
[1] N. Scheerbaum, D. Hinz, O. Gutfleisch, K.-H. Müller, L. Schultz, Acta Mater., accepted. [2] N. Scheerbaum, D. Hinz, O. Gutfleisch, W. Skrotzki, L. Schultz, J. Appl. Phys., accepted.