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MI: Fachverband Mikrosonden

MI 2: Electron Backscattering and Kossel X-Ray Diffraction

MI 2.5: Talk

Monday, March 14, 2011, 11:00–11:15, BEY 81

EBSD analysis of functional magnetic materials — •Thomas George Woodcock, Konrad Güth, Nils Scheerbaum, and Oliver Gutfleisch — IFW Dresden, Institute for Metallic Materials, PO Box 270116, 01171 Dresden, Germany

Functional magnetic materials such as high performance permanent magnets and magnetic shape memory alloys have a broad spectrum of current and potential applications. These range from electric motors in hybrid cars to active damping systems for buildings in earthquake zones. The development of these materials requires the solution of a variety of materials problems. For example, the coercivity mechanism in Nd-Fe-B sintered magnets is known to depend strongly on the Nd-rich phases within the microstructure. EBSD has been used to identify the crystal structure of these phases and study their orientation and defect density. The magnetic remanence of Nd-Fe-B powders processed reactively using hydrogen (HDDR) is known to depend on the alignment of the <001> axes of the grains. This texture is induced during processing and depends strongly on the processing parameters. EBSD has been used to study the texture in such materials, which have a grain size of ~ 300 nm. The magnetic field induced strain in Ni-Mn-Ga based magnetic shape memory alloys is known to be derived from twin boundary motion. EBSD studies of Ni2MnGa fibres following magnetisation along two different directions allowed the position and density of such twin boundaries to be observed.