Mechanical response of a bicontinuous copper-molybdenum nanocomposite: Experiments and simulations

We present the results of a combined experimental and simulation-based study of the mechanical response of a bicontinuous copper-molybdenum nanocomposite, where high strength and good plastic deformability were observed. The experimental sample, prepared by co-sputtering Cu and Mo, achieved a feature size of around 15 nm. Corresponding digital nanostructures with feature sizes between 9 and 15 nm were generated using a phase field model. Virtual compression testing was performed using molecular dynamics simulation. The resultant mechanical response of these samples was analyzed at the macroscopic and atomistic levels. Strain partitioning was observed, where most of the plastic deformation occurs through dislocations that are emitted from the interface into the FCC Cu phase. The interface also acts as a barrier to dislocation propagation. The nanocomposites exhibit high strain hardening rate and plastic co-deformation in Cu and Mo intertwined phases. No shear banding is observed after 30% compression in both experiment and simulation. The bicontinuous, intertwined morphology of metallic FCC/BCC nanocomposites is effective in producing high yield strengths, high strain hardening rate and uniform distribution of plasticity in the sample volume. (C) 2019 Published by Elsevier Ltd on behalf of Acta Materialia Inc.