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

Abstract

We use atomistic modeling 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 below 1200MPa 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.* Corresponding author: demkowicz@mit.edu 617-324-6563 MIT, room 4-142 77 Massachusetts Ave.

High-strength and thermally stable bulk nanolayered composites due to twin-induced interfaces

“…When h refines to 50 nm, the amount of the {112}o1114Cu (C)||{112}o1104Nb interface increases and twins form in the Cu layers 35,36 . The two aforementioned interfaces are ordered, containing regular arrays of facets and interfacial dislocations to accommodate the lattice mismatch between the phases [36][37][38] (see Supplementary Fig. S4).…”

Formation, migration, and clustering of delocalized vacancies and interstitials at a solid-state semicoherent interface

“…Cross-element interactions were fitted to reproduce the high positive dilute enthalpies of mixing of Cu in Nb and Nb in Cu as well as the lattice parameter and bulk modulus of a hypothetical Cu-Nb compound in the Cs-Cl structure 43 . This potential has been used in numerous previous studies of the structure and properties of Cu-Nb interfaces 13,16,40,[44][45][46] .…”

Review on slip transmission criteria in experiments and crystal plasticity models

“…However, it has been found that the local energetic structure and the local stress state of the GB can not be neglected in the context of dislocation interactions near GBs, in general [103]. Additional considerations include, e.g., the interface shear strength [100][101][102]. In the atomistic simulations [105] and in the combined computational / experimental approaches [28], the importance of the RBV for the slip transmission has been demonstrated.…”