The effect of changes in the local atomic structure on the magnetic properties of amorphous iron-based alloys deformed by high-pressure torsion at different temperatures

A Review of Ultrafine-Grained Magnetic Materials Prepared by Using High-Pressure Torsion Method

“…In addition, HPT might be used to fabricate crack-free bulk samples from Fe 73.9 Cu 1 Nb 3 Si 15.5 B 6.6 melt-spun ribbons [ 61 ]. The initially amorphous Fe-Ni-B alloys remain amorphous after HPT at 77 K, while HPT at 293 K leads to a partial crystallization of the amorphous state [ 62 , 63 ]. The saturation magnetization and coercivity of Fe-Ni-B change significantly after HPT processing with respect to the initial state.…”

“…The saturation magnetization and coercivity of Fe-Ni-B change significantly after HPT processing with respect to the initial state. The sharp increase in the coercivity after HPT at 77 K is explained by the absence of relaxation channels for elastic stresses due to the suppression of thermal activation processes [ 63 ]. HPT causes nano-crystallization in amorphous Fe 78 Si 13 B 9 with formation of Fe(Si) nanocrystals, leading to an increase in Ms by 40% [ 64 ].…”