Fabrication of bulk nanocomposite magnets via severe plastic deformation and warm compaction

We demonstrate that a SmCo/FeCo based hard/soft nanocomposite material can be fabricated by distributing the soft magnetic alpha-Fe phase particles homogeneously in a hard magnetic SmCo phase through severe plastic deformation. The soft-phase particle size can be reduced from micrometers to smaller than 15 nm upon deformation. Up to 30% of the soft phase can be incorporated into the composites without coarsening. A warm compaction process of the plastically deformed powder particles then produces bulk nanocomposite magnets of fully dense nanocomposites with energy product up to 19.2 MGOe owing to effective interphase exchange coupling, which makes this type of nanocomposite magnets suitable for high energy-density applications at high temperatures. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3358390]