George Z. Voyiadjis' KTH Solid Mechanics KEYNOTE seminar "Crystal Plasticity Modeling for the strengthening Effect of multilayered Copper-Graphene Nanocomposites"

George Z. Voyiadjisr_Jan_25_2024.pdf (pdf 277 kB)

Abstract. The paper investigates plastic deformation mechanisms in metal-graphene nanocomposite to demonstrate the strengthening effect of materials through a crystal plasticity finite element (CPFE) model comparing published experimental results. The existing experimental research identified that the two-dimensional shape of graphene, which can effectively control dislocation motion, can significantly strengthen metals. Considering the nature of dislocation motions in hundreds of nano-meter length scales, nanopillar compression tests were simulated by using the physics-based CP model that incorporated surface nucleation and single-arm source dislocation mechanisms. The crystal plasticity models have the configuration of a nanolayered composite with layers of copper grains and monolayer graphene sandwiched between them, with repeat layer spacings of 200 nm, 125 nm, and 70 nm, respectively. The present study quantified the accumulation of dislocations at the graphene interfaces, leading to the ultra-high strength of the copper-graphene composite. Furthermore, a Hall-Petch-like correlation was established between yield strength and the number of embedded graphene layers.