Plastic deformation of nanocrystalline copper-antimony alloys

Molecular dynamics simulations are used to evaluate the influence of Sb dopant atoms at the grain boundaries on plastic deformation of nanocrystalline Cu. Deformation is conducted under uniaxial tensile loading, and Sb atoms are incorporated as substitutional defects at the grain boundaries. The presence of randomly dispersed Sb atoms at the grain boundaries does not appreciably influence the mechanisms associated with dislocation nucleation in nanocrystalline Cu; grain boundary ledges and triple junctions still dominate as partial dislocation sources. However, the magnitude of the tensile stress associated with the partial dislocation nucleation event does increase with increasing Sb concentration and also with increasing grain size. The flow stress of nanocrystalline Cu increases with increasing Sb concentration up to 1.0 at.% Sb, with a maximum observed at a grain size of 15 nm for all Sb concentrations (0.0–2.0 at.% Sb).