In-situ atomic-scale observation of dislocation and deformation twin interaction in FeMnCoCr high-entropy alloy

The deformation of a single-crystal Fe₄₈Mn₃₂Co₁₀Cr₁₀ alloy is captured in situ at the atomic scale. The results show that full and partial dislocations, along with deformation twins, are involved in the deformation process. Partial dislocation activities result in the formation of nanotwins, high-density coherent twin boundaries, and incoherent twin boundaries. Full dislocations interact with the coherent/incoherent twin boundaries, and partial dislocations, thereby producing high strength and remarkable strain hardening. The observed high activity of full dislocations can be attributed to the inhomogeneous distribution of solid solution atoms in the alloy.