Influence of defects on mechanical properties of bicrystal copper grain boundary interfaces

Defects play a key role in the determination of material properties, especially at small scales. The influence of several kinds of defects (point vacancies, line vacancies and cracks) on the deformation and fracture characteristics of a planar copper grain boundary interface with a 45° lattice misorientation is explored using molecular dynamics simulations and the embedded-atom method. Both tensile and shear modes of interfacial separation are considered. The results show that the crystalline defects can have a strong influence on the interfacial behaviours. The sensitivity of the mechanical properties of the interface to a defect type may be different under tension than under shear. It is found that some defect topologies can improve certain properties (e.g. strength and fracture strain) of the bicrystal interface system.