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Interfacial bonding of three different semi-coherent bcc-Fe(110)/graphene interfaces is investigated using the plane-wave pseudopotential method within density functional theory. The analysis of bond lengths, charge densities, charge transfer, magnetic moments and densities of states shows that interfacial adhesion can be understood from the electronic structure. Graphene is considered on Fe(110) surfaces as well as embedded in (110) planes of bulk Fe. Moreover, the influence of single vacancies in graphene is studied in case of graphene on the Fe(110) surfaces. It is found that a single vacancy in graphene leads to a strong increase of interfacial adhesion. The most important contribution to the adhesion is covalent bonding with hybridization of Fe states and C states which is most pronounced for neighboring atoms of the vacancy. [Display omitted] • bcc-Fe(110)/graphene interfaces exhibit strong adhesion due to covalent Fe–C bonds. • Single vacancies in graphene lead to a strong increase of adhesion. • Large magnetic moments are induced at C atoms neighboring a single vacancy. [ABSTRACT FROM AUTHOR]

• B substitution of a C atom increases the work of separation on the Fe(110) surface. • There is almost no effect of N on the graphene/Fe(110) interface. • B and N impurities affect the charge states of the nearest C atoms. • Impurities influence on the magnetic state of the nearest Fe atoms. Influence of B and N substitutional impurities on the adhesion properties, electronic and magnetic characteristics of the external and internal graphene/Fe(110) semi-coherent interface was investigated by the projector augmented-wave method within the density functional theory. The analysis of interatomic distances, charge densities, charge transfer and magnetic states of atoms was performed. It was shown that B-doped graphene has a higher adhesion energy on the Fe(110) surface and in the iron bulk in comparison with the undoped systems; whereas, N-doped graphene in the Fe bulk demonstrates the opposite trend and on the surface it has no effect. Boron acts as electron donor that increases charges of the nearest C atoms by 0.5–0.6 e. Nitrogen due to its high electronegativity is an acceptor and as a result the nearest C atoms lose 0.2–0.3 e. Both impurities, depending on the position, influence differently on the magnetic moment of the nearest iron atoms. [Display omitted] [ABSTRACT FROM AUTHOR]

In order to contribute to the understanding of advanced materials with improved mechanical properties we investigate strengthening and failure processes in iron-graphene composites using molecular dynamics simulations. Graphene sheets are embedded in {110} planes of bulk iron. Tensile tests and shear tests are conducted and evaluated with regard to the orientation of the graphene sheet. It is found that two different failure mechanisms involving interfacial fracture and dislocation nucleation can occur due to tensile load. The shear tests revealed three mechanisms of dislocation-obstacle interaction. The highest strengthening was found for graphene sheet orientations which normal vectors are not orthogonal to the Burgers vector of the interacting dislocation. [Display omitted] • Graphene sheet orientation significantly affects failure and strengthening • High CRSS and low UTS with non zero components in tensile and shear direction • Dislocation interaction with graphene is mostly cutting of the matrix • Cutting results in folding, straining and rotation of the sheet. [ABSTRACT FROM AUTHOR]