On the Real‐Time Atomistic Deformation of the CoNiCrFeMn High‐Entropy Alloy with Gradient Structures

Abstract

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.

Strength–Ductility Mechanism of CoCrFeMnNi High-Entropy Alloys with Inverse Gradient-Grained Structures

“…Gradient-grained structures, characterized by significantly disparate mechanical properties from the surface to the interior regions, are considered beneficial for overcoming strength-ductility trade-offs [1][2][3]. Generally, the gradient-grained structure can be divided into two kinds according to the distribution characterization of the grain size.…”