Effect of microstructure, layer thickness, and interface behavior on the plasticity of accumulative roll bonded nanometallic laminates using dislocation dynamics simulations

Abstract

This work aims to understand plastic behavior in different layers of accumulative roll bonded Fe/Al nanometallic laminates (NMLs) using dislocation dynamics simulations. Our simulations start with a synthetic microstructure obtained with an initial pre-deformation followed by a relaxation under zero stress, to represent defect content akin to these NMLs. Subsequently we observe their plastic responses under uniaxial stresses along the transverse (parallel to interface normal) and longitudinal (perpendicular to interface normal) directions for different layer thicknesses. Our simulations suggest significant influence of pre-deformation on the initial dislocation microstructure that also introduces significant plastic heterogeneity between the different layers in the NMLs. We also observe a higher plastic strain per dislocation for Fe layer than the Al layer, as well as, a higher co-deformation and plastic strain under longitudinal loading as compared to transverse loading. Finally comparing the plastic responses from a rigid and a glide interface description, we find that a glide interface doesn’t always account for a higher strain.