The effect of local atomic configuration in high-entropy alloys on the dislocation behaviors and mechanical properties

摘要

High-entropy alloys (HEAs) are promising as advanced structural materials for various applications owning to their comprehensive properties combining high strength and ductility, good thermal stability and high resistance to wear and corrosion. Although such outstanding mechanical properties have been attributed to the four core effects, it is still unclear how the inherent local chemical variations in HEAs affect dislocation dynamics and plastic deformation behaviors at the nanoscale. Herein, we first introduced an accurate in-house potential for Al_xCoCrFeNi HEA, and then employed molecular dynamics simulation methods to investigate the effect of local atomic configuration (LAC) on the dislocation motion, lattice friction and critical shear stress. The results show that compared with pure metals, there is a huge fluctuation in the critical shear stress of dislocation motion in the HEA, indicating that LAC strongly influences the dislocation dynamics and plastic deformation behaviors. It is suggested from the results that introducing large-size atoms in HEA would effectively enhance the dislocation dynamics, which is beneficial to both strengthening and toughening of HEAs.