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

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 areattributed 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.

Automated summary

Molecular dynamic simulations were used to investigate the relationship between gradient structure and mechanical properties in a CoNiCrFeMn high-entropy alloy. The study found that the high strength and work hardening of the gradient HEA are due to concentrated dislocation bundles in grain interiors. The results also showed that the energy barrier for nucleation of deformation faults in the deformed layer of the gradient HEA is higher compared to the ungradient sample.