Atomistic analysis of plastic deformation and shear band formation in FCC/FCC metallic nanolayered composites

Atomistic simulations were used to explore the plastic deformation and shear band (SB) formation in Cu/Au, Cu/Ag, Cu/Al and Cu/Ni metallic nanolayered composites (MNCs). The analysis reveals that interface dislocation structures in all four MNCs are composed of three sets of edge Shockley partial dislocations. Under external loading, dislocations firstly nucleated from the phase with lower stacking fault energy (SFE) in FCC/FCC MNCs. The SBs formed in Cu/Au and Cu/Ag MNCs and the onset strain of SB increases with the increasing layer thicknesses. While in Cu/Al and Cu/Ni MNCs, the deformation is relatively uniform and each slip plane contains similar amounts of dislocations. The formation of SBs in Cu/Au and Cu/Ag MNCs is induced by the nucleation and growth of deformation twinning in the phase with low SFE. After the formation of SBs, the interface sliding accommodates most plastic strains during the deformation.

Automated summary

Atomistic simulations were used to investigate the plastic deformation and shear band formation in Cu/Au, Cu/Ag, Cu/Al, and Cu/Ni metallic nanolayered composites (MNCs). Interface dislocation structures were found to consist of three sets of edge Shockley partial dislocations in all four MNCs. Dislocations first nucleated from the phase with lower stacking fault energy (SFE) under external loading. Shear bands formed in Cu/Au and Cu/Ag MNCs, with the onset strain of shear band increasing with layer thickness. In contrast, deformation in Cu/Al and Cu/Ni MNCs was relatively uniform, with similar amounts of dislocations on each slip plane. Shear band formation in Cu/Au and Cu/Ag MNCs was induced by the nucleation and growth of deformation twinning in the phase with low SFE, with interface sliding accommodating most plastic strains during deformation.