Molecular dynamics simulations were used to study the partial dislocation nucleation process in monocrystalline copper, with 0 to 2at% of antimony, under uniaxial tension. A well-established embedded-atom method potential was used to represent the Cu–Cu interactions and a recently developed Lennard-Jones potential was used for the Cu–Sb and Sb–Sb interactions. The Sb atoms were randomly distributed as substitutional defects in the Cu crystal. Molecular dynamics simulations indicated that the tensile stress required for partial dislocation nucleation in the crystal decreased with increasing Sb concentration. The strain field around Sb dopant atoms in the Cu lattice reduced the unstable stacking fault energy, which promoted heterogeneous nucleation of partial dislocations and reduced the tensile stresses required for plastic deformation. The role played by Sb in reducing the stress required for dislocation nucleation was found to be orientation-dependent. Both the temperature and the Sb distribution played a role in the statistical variation of the stress required for heterogeneous partial dislocation nucleation. This variation was greatest for 0.20 to 0.50at%Sb.

Heterogeneous Dislocation Nucleation in Single Crystal Copper–Antimony Solid-Solution Alloys. R.K.Rajgarhia, D.E.Spearot, A.Saxena: Modelling and Simulation in Materials Science and Engineering, 2009, 17[5], 055001 (13pp)