Regensburg 2010 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 8: Magnetic Shape Memory Alloys
MA 8.14: Vortrag
Montag, 22. März 2010, 18:45–19:00, H22
Magnetic field induced strain in Ni2MnGa-Polymer-Composites — •Sandra Weiß1, Nils Scheerbaum1, Jian Liu1, Ludwig Schultz1, Oliver Gutfleisch1, Edith Mäder2, and Gert Heinrich2 — 1IFW Dresden, Institute for Metallic Materials, P.O. Box 270116, D-01171 Dresden — 2Leibniz-Institut für Polymerforschung e.V., Hohe Straße 6, 01069 Dresden
Ni-Mn-Ga single- and polycrystals show large magnetic field induced strain (MFIS) but are in general difficult and expensive in preparation and also very brittle. An alternative to single- and polycrystals are Ni-Mn-Ga/polymer-composites. Here, small single-crystalline Ni50.9Mn27.1Ga22.0-particles, produced by gently crushing melt-extracted and subsequently annealed fibres, were embedded in a soft polymer matrix. The particles have a 5M martensitic structure. The Young’s Modulus of the polymer-matrix is 2 MPa and 175 MPa, for polyurethane and epoxy respectively. In response to the applied magnetic field, the MSM particles are prone to relocation within the polyurethane due to its low Young’s modulus, leading to a very little effect of magnetic field-induced twin boundary motion. By contrast, the Ni2MnGa-epoxy-composite shows a pronounced MFIS up to 0.1 % because the stiffness of epoxy fits better the one for Ni-Mn-Ga. Furthermore, the interface stability between Ni-Mn-Ga and epoxy-matrix was investigated by quasistatic Pull-Out Tests. First tests with silan-coupling-agent treated fibres indicate significant improvements of interface.