Atomistic Insights Into Edge Dislocations and Grain Boundaries Effects on Mechanical Properties in CrFeMnNi High Entropy Alloy

ABSTRACT This study employs molecular dynamics (MD) simulations to investigate the mechanical properties of the high entropy alloy (HEA) with grain boundaries Σ5 and Σ13, as well as the structure without GBs and edge dislocations. To evaluate size‐dependent effects, models of increasing dimensions (initial, four times larger, 9th times larger) were examined. The outcomes of our study reveal that the variation in atomic sizes among constituent elements causes lattice distortion, leading to deformation in HEAs. GB Σ5 exhibited increased strength and hardness, as evidenced by Young's modulus of 271.86 GPa, bulk modulus of 177.17 GPa, and shear modulus of 109.25 GPa, all higher than those of the non‐GB system. In contrast, GB Σ13 demonstrated superior ductility, with Cauchy's pressure of 52.64 GPa, Poisson's and Pugh's ratios of 0.311 and 2.31, respectively, based on the initial model. The mechanical properties of HEA were seen to be greatly affected by the grain boundaries, which in turn influenced the ductility. Additionally, the study highlights that the inclusion of edge dislocations and grain boundaries significantly improves the yield strength of the HEA boosts its overall mechanical performance. This study reveals how grain boundaries affect HEAs' mechanics, highlighting GB engineering and dislocations for stronger, high‐performance materials design.