An EAM potential for α-brass copper–zinc alloys: application to plasticity and fracture

An embedded atom method potential has been developed for copper–zinc alloys valid from 0% to 37% zinc content (dedicated to describe the α fcc phase). It has been fit to a set of first-principles data for the fcc copper, the fcc Cu₃Zn DO₂₃ phase and Zn on a fcc lattice. Elastic anisotropies, the lattice parameter, cohesive energy are used as input. Ponctual defects, surface energies, intrinsic stacking fault and phonon spectrum have been computed and compare well with experimental trends. This potential has been used to study dislocation dissociation and dislocation emission at a crack tip up to 30% Zn. Dislocation emission at the crack tip is correctly described compared with recent parametrization including the surface energy. It is found that with alloying, dislocation emission becomes easier following the decrease of the unstable stacking fault energy with Zn concentration, a non-trivial finding. This potential is therefore well suited to carry out basic studies of plasticity and fracture in α-brass alloys.