BSTRACTIt has been shown that unlike its constituent nanocrystalline (NC) phase

a heterogeneous lamella (HL) composite comprising NC and coarse-grain layers exhibits greatly improved ductility. To understand the origin of this enhancement

we present a 3D discrete dislocation

crystal plasticity finite element model to study the development of strains across this microstructure. Here we show that the HL structure homogenizes the plastic strains in the NC layer

weakening the effect of strain concentrations. These findings can provide valuable insight into the effects of material length scales on material instabilities

which is needed to design heterogeneous structures with superior properties.