Structure and magnetic properties of nanocrystalline SmCo5 and SmCo3Cu2 prepared by using high-pressure torsion method

Nanocrystalline SmCo5 and SmCo3Cu2 alloys were prepared by using high pressure torsion (HPT) method. The effect of severe plastic deformation of HPT on the structure and magnetic properties of the samples were investigated systematically. The grain size of SmCo5 and SmCo3Cu2 alloys was refined to the nanocrystalline regime or even amorphous state by HPT, depending on the number of the HPT rotation. Lamellar microstructures of the grains were observed in the samples after HPT for 2 turns of rotation. With increasing number of HPT rotation, a further structural refinement and an increasing coercivity were observed. The coercivity of the as-cast SmCo5 and SmCo3Cu2 alloys after HPT reached up to 0.5 and 1.64 T, respectively. This work demonstrates that HPT is a high efficiency method in producing bulk nanocrystalline magnetic materials.