Real-time atomic deformation behavior of nano CoCrCuFeNi high-entropy alloy
(1. College of Automobile and Mechanical Engineering, Changsha University of Science and Technology, Changsha 410114, China;
2. College of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China)
2. College of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China)
Abstract: Tensile tests were performed by molecular dynamics at various strain rates ranging from 2×108 to 1×1010 s-1 and various temperatures ranging from 10 to 1200 K, and the real-time deformation behavior of a nanocrystalline CoCrCuFeNi high-entropy alloy was investigated. The results indicate that the main deformation mechanism is grain boundary slip at high temperatures and low strain rates. Dislocation slip replaces grain boundary slip to control plastic deformation with decreasing temperature and increasing strain rate, correspondingly enhancing the strength of the alloy. Furthermore, the alloys with different grain sizes were simulated to evaluate the effects of grain boundaries on the mechanical behavior. It is found that the strength of the nanocrystalline high-entropy alloys increases with increasing grain sizes when the grain size is too small, exhibiting an inverse Hall-Petch relationship.
Key words: nanocrystalline high-entropy alloy; dislocation evolution; deformation mechanism; strain rate; grain size