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.