Impact of compositional fluctuations on the mechanical behavior of Ni-Co solid solution alloys investigated by molecular dynamics simulations

R Liu and LY Cheng and L Chen and JF Li and LT Kong, MATERIALS TODAY COMMUNICATIONS, 48, 113607 (2025).

DOI: 10.1016/j.mtcomm.2025.113607

Molecular dynamics simulations were conducted to investigate the influence of compositional fluctuations on mechanical behavior of equiatomic Ni-Co solid solution alloys. The results reveal that compositional fluctuations significantly impact the stacking fault energy (SFE), and in turn the dislocation slip behavior of the alloys. The enhanced local SFE results in elevated Peierls energy barriers, impeding dislocation motion. It also induces increased dislocation line curvature, further hindering its migration. Additionally, local stress fields induced by compositional fluctuations also enhance the resistance to dislocation motion, thereby strengthening the material. Meanwhile, spatial variations in SFE facilitate dislocation accumulation, allowing for improved plastic deformation and ductility. By controlling compositional heterogeneity and introducing fluctuations with wavelengths exceeding the spacing between partial dislocations in a random solid solution, a synergistic enhancement of strength and ductility can be achieved. These findings provide valuable insights for optimizing the mechanical properties of advanced materials.

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