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The nanocrystalline metallic bilayer structure can effectively enhance the strength of Cu alloy while maintaining excellent electrical conductivity. Based on the microstructure evolution of Cu/Ag alloy observed by transmission electron microscope (TEM), molecular dynamics (MD) simulations of Cu/Ag alloy with nanocrystalline metallic bilayer structure were established. The mechanical properties and deformation mechanisms of nanocrystalline Cu/Ag-bilayer alloys were investigated at different temperatures. A mixed Hall-Petch (H-P) relationship was observed between the ultimate stress and the increased layer thickness. In this paper, the deformation mechanism changes from dislocation accumulation at the Cu-Ag interface to dislocation through the Cu-Ag interface. In addition, the data analysis results of elastic modulus showed an approximately linear decrease trend with increasing temperature, and the deformation mechanism shifted from dislocation motion to a combination of dislocation motion and grain boundaries (GBs) diffusion. These findings provide guidance for the design of high magnetic field facility (HMFF) water-cooled magnets and very large-scale integration (VLSI) lead frames. • The deformation behaviour of the nanocrystalline Cu/Ag-bilayer alloy at different thicknesses (4–6 nm) and temperatures (1–800 K) is investigated. • The layer thickness of Cu/Ag-bilayer alloy conforms to the mixed H-P relationship. The mechanism changes from dislocation pile-up. • As temperatures increases, the deformation mechanism transformed from dislocation emission to a combination of dislocation motion and the high-temperature softening. [ABSTRACT FROM AUTHOR]

In this paper, three different configurations of composite materials models of TiB 2 /Cu homogeneous structure, single TiB 2 /Cu network structure and hybrid reinforced (TiB 2p +TiB w)/Cu network structure are established based on their actual microstructure. The models take into account the ductile fracture of the matrix, the brittle fracture of the reinforcing phase and the traction separation behavior of the interface. Influence of mesh size and mass scaling factor on the simulation results are discussed. The validity of the simulation results is verified by the agreement of the experimental tensile stress-strain curve. The effects of TiB 2 particle size, volume fraction and hybrid effects of TiB 2p +TiB w on plastic deformation and mechanical properties of composites are assessed from the three aspects: interface damage, load-bearing capacity of reinforcement and matrix damage. Compared with the TiB 2 /Cu homogeneous composites and the single TiB 2 /Cu network composites, the hybrid reinforced (TiB 2p +TiB w)/Cu network composites has better comprehensive mechanical properties, and its tensile strength and elongation are 349 MPa and 10.6 %, respectively. The addition of whiskers can effectively improve the bearing capacity of the hybrid reinforced (TiB 2p +TiB w)/Cu network composites, but reduce the elongation of composites. [Display omitted] • Models of homogeneous composites, single TiB 2 network composites and hybrid TiB 2p +TiB w network composites are established. • The particle size, volume fraction and the hybrid effects of TiB 2p +TiB w on the deformation of composites are studied. • The composites are assessed from the three aspects: interface damage, load-bearing capacity of and matrix damage. [ABSTRACT FROM AUTHOR]