Atomistic Simulation of Tensile Deformation Behavior of Sigma 5 Tilt Grain Boundaries in Copper Bicrystal

L Zhang and C Lu and K Tieu, SCIENTIFIC REPORTS, 4, 5919 (2014).

DOI: 10.1038/srep05919

Experiments on polycrystalline metallic samples have indicated that Grain boundary (GB) structure can affect many material properties related to fracture and plasticity. In this study, atomistic simulations are employed to investigate the structures and mechanical behavior of both symmetric and asymmetric Sigma 50 0 1 tilt GBs of copper bicrystal. First, the equilibrium GB structures are generated by molecular statics simulation at 0K. The results show that the Sigma 5 asymmetric GBs with different inclination angles (phi) are composed of only two structural units corresponding to the two Sigma 5 symmetric GBs. Molecular dynamics simulations are then conducted to investigate the mechanical response and the underlying deformation mechanisms of bicrystal models with different Sigma 5 GBs under tension. Tensile deformation is applied under both 'free' and 'constrained' boundary conditions. Simulation results revealed different mechanical properties of the symmetric and asymmetric GBs and indicated that stress state can play an important role in the deformation mechanisms of nanocrystalline materials.

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