Magnetic characteristics of HPT deformed soft-magnetic materials

Five sets of soft-magnetic metals, such as pure Fe, pure Ni, Fe-3 wt% Si, Fe-6.5 wt% Si and Fe-17 wt% Co, were subjected to high pressure torsion (HPT) up to strain levels where a saturation of the microstructural refinement is observed. Following HPT at 77, 293 and 723 K, transmission electron micr...

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Bibliographic Details
Published in:Journal of magnetism and magnetic materials 2010-10, Vol.322 (20), p.2984-2988
Main Authors: Scheriau, S., Kriegisch, M., Kleber, S., Mehboob, N., Grössinger, R., Pippan, R.
Format: Article
Language:English
Subjects:
Coercive force
Coercivity
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Cross-disciplinary physics: materials science
rheology
Crystallites
Deformation
Deformation, plasticity, and creep
Domain effects, magnetization curves, and hysteresis
Exact sciences and technology
FeCo
Fe–Si
Grain size
HPT
Iron
Magnetic properties and materials
Magnetization curves, magnetization reversal, hysteresis, barkhausen and related effects
Materials science
Microstructure
Physics
Silicon
Treatment of materials and its effects on microstructure and properties
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Summary:Five sets of soft-magnetic metals, such as pure Fe, pure Ni, Fe-3 wt% Si, Fe-6.5 wt% Si and Fe-17 wt% Co, were subjected to high pressure torsion (HPT) up to strain levels where a saturation of the microstructural refinement is observed. Following HPT at 77, 293 and 723 K, transmission electron microscopy (TEM) was used to study the grain size and grain shape of the severely deformed metals. The coercivity H C was characterized in a magnetic closed system by using ring shaped samples. Magnetic measurements obtained on ring shaped samples give a much higher accuracy for determining the coercivity. Depending on the material the mean microstructural sizes in the steady state vary from 300 nm at 723 K to 30 nm at 77 K, respectively. The coercivity of the deformed materials first increases with decrease in grain size. Once the crystallite size is far below 100 nm the coercivity shows a strong decrease.
ISSN:0304-8853
DOI:10.1016/j.jmmm.2010.04.032