Single layer graphene controlled surface and bulk indentation plasticity in copper

The impact of graphene reinforcement on the mechanical properties metals has been a subject intense investigation over last decade in surface applications to mitigate tribological loadings or for strengthening purposes when dispersed into bulk material. Here, effect plastic indentation response single layer grown copper is analyzed two configurations: one with at surface, other sandwiched under 100 nm thick cap layer. Nanoindentation both displacement and load control conditions show earlier shorter pop-in excursions compared systems without graphene. Atomic force microscopy reveals much smoother pile-ups no slip traces presence configuration intercalated appears as an ideal elementary system address hardening mechanisms by testing. Transmission electron (TEM) cross-sections below indents more diffuse homogeneous dislocation activity 3D dynamics simulations allow unraveling origin these complex phenomena prove that collective are dominantly controlled strong back stress caused barrier. These results provide quantitative understanding applications, but not large anticipated from studies general literature claims.