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Abstract
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Molecular dynamic simulations are used to correlate gradient structure and
mechanical properties of a CoNiCrFeMn high-entropy alloy (HEA) by characterizing the structural evolution and dislocation substructures during tensile
loading. The gradient distributions of deformation faults, dislocations, and grain
size from the surface to the center of samples are explored in detail.
Quantitative analysis indicates that improvement of strength is attributed to the
high densities of dislocations and deformation faults in the grain interior.
Moreover, the results reveal that the energy barrier for nucleation of deformation
faults in the deformed layer of gradient HEA is higher than that of the ungradient
sample. The high strength and work hardening of gradient HEA are
attributed to the bundles of concentrated dislocations, which are distributed in
grain interiors. This study helps to fundamental understanding of the deformation mechanisms of HEAs with gradient structure, which can be used to
strength-ductility trade-off.
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