Influence of bimetal interface confinement on the Hall-petch slope of multiscale Cu/Nb multilayer composites

Heterostructured materials afford a new way to improve the mechanical properties, which has become vital in both materials science and engineering applications. In the present research, Cu/ Nb multilayer composites with layer thicknesses from the micrometer to nanometer were fabri-cated by accumulative roll bonding and the microstructure and mechanical properties of the Cu/ Nb multilayer composites were then investigated. The yield strength and ultimate tensile strength of these composites increase with decreasing layer thickness. Moreover, the relationship between yield strength and (layer thickness)-1/2 approximately accords with the conventional Hall-Petch equation but with a decrease in the Hall-Petch slope when the layer thickness decreases from the micrometer to nanometer scales. The deformation microstructure of these Cu/Nb multilayer composites clearly exhibit dislocations glide in the layers, which reduces the stacking of dislo-cations at the Cu-Nb interface and thereby weakens the strengthening effect of the interface.

Automated summary

Heterostructured materials offer a new approach to enhancing mechanical properties, which are crucial in materials science and engineering. In this study, Cu/Nb multilayer composites with varying layer thicknesses were produced using accumulative roll bonding and their microstructure and mechanical properties were investigated. The yield strength and ultimate tensile strength of these composites increase as the layer thickness decreases. Additionally, the relationship between yield strength and (layer thickness)-1/2 approximately follows the conventional Hall-Petch equation, but with a reduction in the Hall-Petch slope for nanometer-scale layer thicknesses. The deformation microstructure of these Cu/Nb multilayer composites reveals dislocation glide within the layers, leading to a weakening of the strengthening effect at the Cu-Nb interface.