Molecular dynamics study on the grain boundary dislocation source in nanocrystalline copper under tensile loading

Grain boundary (GB) is the interface between different oriented crystals of the same material, and it

can have a significant effect on the many properties of materials. When the average or entire range of

grain size is reduced to less than 100 nm, the conventional plastic deformation mechanisms

dominated by dislocation processes become difficult and GBmediated deformation mechanisms

become increasingly important. One of the mechanisms that can play a profound role in the strength

and plasticity of metallic polycrystalline materials is the heterogeneous nucleation and emission of

dislocations from GB. In this study, we conducted molecular dynamics simulations to study the

dislocation nucleation from copper bicrystal with a number of 〈1 10〉 tilt GBs that covered a wide

range of misorientation angles (θ).Wewill show from this analysis that the mechanic behavior of GBs

and the energy barrier of dislocation nucleation from GBs are closely related to the lattice

crystallographic orientation, GBenergy, and the intrinsic GBstructures. An atomistic analysis of the

nucleation mechanisms provided details of this nucleation and emission process that can help us to

better understand the dislocation source in GB.