Dislocation Structure of Cu/Nu (100) Semi-Coherent Interface and Its Role in Lattice Dislocation Nucleation

Using molecular dynamics simulations and dislocation theory, we studied dislocation structure of Cu/Ni (100) semi-coherent interface and its role in nucleating lattice dislocation under mechanical loading. We found that misfit dislocation pattern is dependent on layer thickness. On each interface, there are two sets of edge-type misfit dislocation with the Burgers vector of 1/2<110> and the line sense along <1–10>. The relative position of misfit dislocations at the adjacent interfaces is related to the layer thickness. This is ascribed to two factors, interaction energy among misfit dislocations and the core dissociation of misfit dislocations. Both of them show layer thickness dependence. Under mechanical loading, lattice dislocations nucleate from misfit dislocation lines. Thus, the incipient of plastic deformation of layered Cu/Ni composites in terms of initial yielding stress is dependent on the layer thickness.