Atomistic modeling of dislocations in a random quinary high-entropy alloy

Abstract

The structure and mobility of dissociated ½〈1 1 0〉 dislocations in a model FCC high entropy alloy is studied using atomistic simulations. The simulations are performed using model embedded atom method (EAM) potentials for a model five component random equiatomic alloy, and a corresponding “average atom” potential. The dislocation line that corresponds to minimum energy in the complex alloy is not straight but wavy and significant variations in dissociation distances are found. This effect is more significant for edge dislocations than for screw dislocations. Calculations also show that both the stable and unstable stacking fault energies vary according to the local composition of the alloy. The range of Peierls stresses computed for the dislocations in the alloy are significantly higher than in the pure components or those computed using an average atom potential.