Structure, shear resistance and interaction with point defects of interfaces in Cu-Nb nanocomposites synthesized by severe plastic deformation

Atomistic modeling is used to investigate the shear resistance and interaction with point defects of a Cu-Nb interface found in nanocomposites synthesized by severe plastic deformation. The shear resistance of this interface is highly anisotropic: in one direction shearing occurs at stresses <1200 MPa, while in the other it does not occur at all. The binding energy of vacancies, interstitials and He impurities to this interface depends sensitively on the binding location, but there is no point defect delocalization, nor does this interface contain any constitutional defects. These behaviors are markedly dissimilar from a different Cu-Nb interface found in magnetron sputtered composites. The dissimilarities may, however, be explained by quantitative differences in the detailed structure of these two interfaces.