Dislocation nucleation in CoNiCrFeMn high entropy alloy

Abstract

In this work, the homogeneous and heterogeneous nucleation of dislocations in a representative face-centered-cubic high entropy alloy (HEA) CoNiCrFeMn is studied by combining molecular dynamics simulations and continuum mechanics modeling. It is found that as compared to conventional metals such as Cu, HEAs have relatively low activation energy but require high athermal stress for dislocation nucleation. This seemingly odd behavior originates from the uniquely low (even negative) stacking fault energy in HEAs that leads to low critical nucleation radius and low activation volume for dislocation nucleation.