Effect of Frenkel pairs on the tensile and shock compression strength of multi-elemental alloys

Abstract

In this article, molecular dynamics simulations were performed to study the effect of irradiation damage on the tensile and shock compression behaviour of multi-elemental alloys (medium and high entropy alloys). These simulations were divided into three broad stages; in the first section, a displacement cascade was generated in the simulation box using primary knock-on atoms (PKA) with kinetic energy in the range of 0.25 to 2 keV. In the second stage, the same defected crystal was subjected to tensile loading to study the deformation mechanism of multi-elemental alloys containing these irradiation-induced defects. In the last stage, tensile loading was replaced by ultrashort shock pulse loading. Irradiation damage significantly alters the tensile strength of Fe-Ni-Co-Cr-Cu and Fe-Ni-Cr alloys. The primary deformation governing mechanism is the spatial distribution of stacking faults and partial dislocations during deformation. Lattice distortion reduces the tensile strength of multi-elemental alloys compared to A-atom configurations. In shock loading, the shock resistance capability of irradiated Fe-Ni-Co-Cr-Cu was better than Fe-Ni-Cr alloy. Lattice distortion in random multi-elemental alloys helps in mitigating the shock propagation.