Regensburg 2007 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 4: Liquid and amorphous materials II

MM 4.3: Vortrag

Montag, 26. März 2007, 12:15–12:30, H4

Metallurgical considerations in the development of ferromagnetic Fe-based metallic glasses — •Giovanni Mastrogiacomo and Jörg Löffler — Laboratory of Metal Physics and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Str. 10, 8093 Zurich, Switzerland

Despite intense research activity concerning the glass-forming ability of metallic alloys, the crucial metallurgical parameters for improving glass-forming ability are still not well understood. Considering the crystallization of several bulk metallic glasses which decompose in the deeply undercooled liquid region, we developed Fe-based bulk metallic glasses by a further destabilization of the Fe–Cr–Co system. This system tends to decompose in iron-rich and chromium-rich b.c.c. phases [1]. The liquidus temperature was systematically reduced by alloying elements which satisfy the empirical rules suggested by Hume-Rothery and destabilize the high temperature austenitic phase. The resulting metallic glasses of composition (Fe_0.582Co_0.418)₈₀Cr₁₀Zr₁₀ and [(Fe_0.582Co_0.418)_0.81Cr_0.1Zr_0.07Ti_0.02]₉₀B₁₀ reveal unexpected magnetic properties, as, for example, inverted major and exchange-biased minor hysteresis loops [2,3]. These results are discussed considering the decomposing tendency of the Fe–Cr–Co system.

[1] F. Zhu, P. Haasen, and R. Wagner, Acta Metall. 34, 457 (1986).

[2] G. Mastrogiacomo et al., J. Appl. Phys. 99, 023908 (2006).

[3] G. Mastrogiacomo et al., J. Appl. Phys. 100, 12xxxx (2006).