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Invar Effect of Fe-Based Amorphous and Nanocrystalline Alloys

Author: LuZhiChao
Tutor: LaiZuHan;XianYuZe
School: Northeastern University
Course: Materials Physics
Keywords: Invar effect amorphous alloy nanocrystalline alloy generalized phonon density of states valence electronic density of states inelastic neutron scattering
CLC: TG139.8
Type: PhD thesis
Year: 1994
Downloads: 264
Quote: 1
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Abstract


Because Invar problem is closely connected with the physical origin of ferromagnetism in 3d transition metals and alloys, it has been one of the most important subjects in the field of magnetic physics. This thesis systematically studied various anomalies and their relationship for amorphous Fe-Zr based Invar alloys, and placed emphasis on the dynamical properties which were not ever reported in the literatures. Some new phenomena were experimentally found, and a possible mechanism of Invar effect was proposed in terms of electron-phonon interaction(EPI). In addition, a few of quesitions related to Invar effect were discussed in Fe-based nanocrystalline alloys. In detail, the thesis includes following parts:1. Macroscopic (Static) properties and their relationship in amorphous Fe—Zr based (TM—TM) Invar alloys.The Fe in an amorphous Fe90Zr10 Invar alloy were replaced by the ferromagnetic element Co and the antiferromagnetic element Cr, and the thermal expansion curves, R-T curves, saturation magnetic moment and temperature dependence of magnetization were measured for amorphous Fe-(Co, Cr)-Zr alloys. The inflence of variation of the average number of valence electrons (Neff) on the magneto-volume effect, the anomalous behavior of electrical resistivity and the magnetism was analyzed. The following new results were achieved:(1) The spontaneous volume magnetostriction (ωs) is a maximum at Neff≈8.2, which is quite similar to that of amorphous Fe-B based (TM-M) alloys. This result provides a experimental evidence

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CLC: > Industrial Technology > Metallurgy and Metal Craft > Metallurgy and Heat Treatment > The alloy learn with a variety of properties of alloys > Other special nature of the alloy > Amorphous alloy
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