Plasticity enhancement in 25Cr15Co hard magnetic alloy deformed in bridgman anvils

In the work, we studied the evolution of structural and mechanical properties of 25Cr15Co hard magnetic alloy under shear deformation in Bridgman anvils at different rotation angles. It is shown that at the initial stage, severe plastic strains in a highly coercive (α₁ + α₂) state are localized in shear bands, in which the α₁ and α₂ phases are dissolved and an oversaturated a solid solution is formed. As this takes place, there arises a mixed structure consisting of misoriented fragments of the (α₁ + α₂) phase surrounded by interlayers of the a solid solution. A further increase in strain degree results in a single-phase nanocrystalline structure with a grain size of about 50 nm. It is found that the dissolution of the α₁ phases in the α₂ matrix under severe plastic deformation causes an increase in the strength characteristics and plasticity of 25Cr15Co alloy at all strain degrees under study. Maximum plasticity is found in the alloy with a mixed structure consisting of submicrocrystalline and cellular sites, and formation of nanocrystalline grains causes the plasticity to decrease somewhat.