Crack tip behaviour in a non-equi-atomic configurations of multiple elemental alloys: a MD based study

Abstract This article aims to study the crack tip behavior in non-equi-atomic configurations of high entropy alloy (Fe-Ni-Cu-Cr-Co). Atomistic simulations were performed in conjunction with the embedded atom method force field. The crack trip behavior has been studied to analyze the lattice distortion effect. Two different configurations were generated for atomistic simulations (random atom and average atom) to quantify the effect of lattice distortion in high entropy alloys. Five elements (Fe-Ni-Cu-Cr-Co) were considered in random alloy configuration, whereas, in average atom (A-atom) configuration, a virtual atom replaced the five elements in the simulation box. It was predicted from the simulations that crack propagation was aborted in random alloy configuration, whereas catastrophic failure was observed in average atom configuration under mode-I loading. The effect of lattice distortion governs the failure in random alloy configuration. It can be inferred from the simulations that the lattice distortion effect is dominant in the configurations containing higher weight percentages of Cu and Ni. It can be concluded from this work that fracture toughness can be tailored using the non-equi-atomic configurations of high entropy alloys. The emergence of additive manufacturing techniques can quickly fabricate the samples of non-equi-atomic configurations of high entropy alloys.