Regensburg 2004 – scientific programme

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M: Metallphysik

M 19: Hauptvortrag Jorg Wiezorek

M 19.1: Invited Talk

Wednesday, March 10, 2004, 14:00–14:30, H16

Combined Reaction Processing of Fe-Pd based Ferromagnetic Intermetallics — •Jorg Wiezorek — UPitt: MSE, University of Pittsburgh, 848 Benedum Hall, Pittsburgh, PA 15261, USA

Jörg M.K. Wiezorek Department of Materials Science and Engineering, University of Pittsburgh, 848 Benedum Hall, Pittsburgh, PA, USA.

Alloys based on Fe and Pd are of interest for permanent magnet applications due to the large uniaxial magnetocrystalline anisotropy associated with the formation of the L1o-ordered intermetallic phase, gamma1-FePd. However, the magnetic properties of FePd after conventional processing are disappointing. Optimization of the technical properties of FePd ferromagnets requires the development of a detailed understanding of the phase-transformation and microstructural transformation behavior. Here, thermo-mechanical processing, termed combined reaction (CR) processing, was used to control microstructural scale and morphology and to improve the properties of FePd. CR processing exploits the interplay between recrystallization and the ordering transformation during annealing after cold-work at T<Tc. SEM, TEM XRD and VSM have been used for microstructural and property studies. The CR processed FePd exhibits refined grain sizes and enhanced coercivity compared with conventionally processed material. Models to rationalize the eexperimental results are proposed. CR processing appears suited for application to a broad range of ordering intermetallics.