Inverse Hall-Petch relationship of high-entropy alloy by atomistic simulation

Molecular dynamics simulations were carried out to investigate the mechanical properties and the Hall-Petch effect of high-entropy alloy using the interatomic potential for the multi-element FeNiCrCoCu. The transition from mechanical strengthening to softening was observed for the simulated samples with the mean grain size ranging from 28.44 to 5.33 nm. The critical grain size of the inverse Hall-Petch relationship increases with the increase of temperature from 10 K to 600 K. Deformation mechanisms caused by grain boundaries and the dislocation activities are involved in accommodating the system stress in the small grain samples during plastic deformation.