TY - JOUR AB - 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 723K, transmission electron microscopy (TEM) was used to study the grain size and grain shape of the severely deformed metals. The coercivity HC 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. AU - Scheriau Stephan, Kriegisch M., Kleber Siegfried, Mehboob N., Grössinger R., Pippan Reinhard DA - 2010/05/21/ IS - 322 JF - Journal of Magnetism and Magnetic Materials PY - 2010 SE - 2010/05/21/ SP - 2984-2988 TI - Magnetic characteristics of HPTdeformed soft-magnetic materials ER -