Deformation-induced grain refinement in body-centered cubic Co–Fe alloys upon room temperature compression

Pronounced grain refinement to ultrafine or nanoscale size in initially coarse-grained Co–25Fe and Co–35Fe alloys has been achieved upon conventional compression at room temperature. Both Co–Fe alloys exhibit a large plasticity of more than 140% without fracture at room temperature, which is related to a multiscale-grained microstructure resulting from deformation-induced grain refinement. The grains refine with increasing deformation during compression. The microstructure features indicate that the possible mechanism for the strain-induced grain refinement under conventional compression is a consequence of the propagation and coalescence of dislocation cell structures with strain accumulation.