Utilizing partial recrystallization to overcome strength ductility trade-off of CoCrFeNi high entropy alloy

The effects of cold rolling and annealing conditions on the microstructural evolution and mechanical properties of CoCrFeNi were investigated. Analysis of the microstructure of the CoCrFeNi alloy revealed that the deformation process is governed by a combination of dislocation slip, kinking, and twinning. The presence of these high-density dislocation regions facilitates recrystallization nucleation during annealing. Consequently, as deformation increases, the nucleation area of recrystallization expands, and grain size is influenced by surrounding grains, resulting in the formation of fine recrystallized grains. Within a specific range of annealing temperatures and durations, when alloy deformation remains constant, the average grain size initially decreases and subsequently increases. Analysis of mechanical properties in the CoCrFeNi alloy demonstrates that the strengthening effect of rolling is retained in partially recrystallized conditions obtaining excellent mechanical properties matching strength and plasticity.