Temperature and Crystalline Orientation-Dependent Plastic Deformation of FeNiCrCoMn High-Entropy Alloy by Molecular Dynamics Simulation

Abstract

The effect of the crystallographic direction and temperature on the mechanical properties of an FeNiCrCoMn high-entropy alloy (HEA) is explored by molecular dynamics simulations. The calculated static properties are in agreement with the respective experimental/early theoretical results. The calculated compressive yield stress along the <010> direction of a single crystal/polycrystal is the same in order of magnitude as the experimental results. The yield stress and Young’s modulus of the single crystal show strong anisotropy. Unlike the single crystal, the polycrystal behaves as an isotropic and has strong ductility. It is found that the dislocations produced in the plastic deformation process of the HEA are mainly 1/6<112> Shockley dislocations. The dislocations produced under normal stress loads are far more than that in the shearing process. FCC transformation into HCP does not occur almost until yield stress appears. The yield stress, yield strain, and Young’s modulus reduce gradually with increasing temperature. The modulus of the single/double crystal under compressive and tensile loads presents an obvious asymmetry, while there is only a small difference in the polycrystal. The strain point is found to be the same for stress yielding, FCC-HCP phase transition, and dislocation density, varying from slow to fast with strain at the considered temperature.