Unveiling the deformation behaviors and mechanisms of Fe2.5Ni2.5CrAl multi-principal elements alloy

L Qiao and JC Zhu, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 931, 148154 (2025).

DOI: 10.1016/j.msea.2025.148154

The Fe2.5Ni2.5CrAl multi-principal element alloy (MPEA) possesses an excellent combination of strength and plasticity. However, the underlying deformation mechanisms are unclear. Hence, experimental characterization combined with molecular dynamics (MD) simulations were performed to elucidate the compressive behavior. The grain showed preferred crystallographic orientations of 001 after deformation. The formation of dislocation structures and twin bands contributed to the high strength and good plasticity of Fe2.5Ni2.5CrAl MPEAs. MD results indicated that single crystals and polycrystals exhibited different mechanical characteristics during compression. The strength of polycrystals was higher than that of single crystals due to the effect of fine grain strengthening. The phase structure, atomic shear strain and dislocations during compression were analyzed. A phase transformation from the FCC to HCP structure was revealed. Plastic deformation resulted in stacking faults (SFs) and parallel twin formation. The extent of twinning and growth of these SFs contribute to the high plasticity of Fe2.5Ni2.5CrAl MPEAs. The role of grain boundaries (GBs) were discussed, promoting shear-accommodating mechanisms like twinning and GBs sliding. The mixed intersections of GBs and SFs play significant roles in the plastic deformation. Thus, this study has elucidated the compressive mechanical behavior of Fe2.5Ni2.5CrAl MPEAs and the origin of the outstanding combination of strength and plasticity of this material.

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