Atomic-scale mechanisms of single crystal plasticity in CoCrFeMnNi high-entropy alloys

Abstract

The behavior of CoCrFeMnNi high-entropy alloys under mechanical loading was studied within the framework of the molecular dynamics method. The mechanisms of local structural transformations of the crystal lattice responsible for the onset of plasticity at the tension of CoCrFeMnNi single crystals were determined. A crystallographic analysis of the structure and identification of the defects formed was carried out. Irrespectively on stoichiometric composition of samples the plasticity is realized by the nucleation, growth and intersection of intrinsic stacking faults. Rearrangement of fcc lattice to bcc structure in the regions where the local atom fraction of Fe, Mn and Ni is above average was found to be the mechanism of stacking fault formation. The effect of the stoichiometric composition and crystallographic orientation of single-crystal CoCrFeMnNi samples upon the structural rearrangements at the nucleation and development of plastic deformation under tension was studied.