Abstract
Record high values of Young's modulus and tensile strength of graphene and BN nanoribbons as well as their chemically active edges make them promising candidates for serving as fillers in metal-based composite materials. Herein, using ab initio and analytical potential calculations we carry out a systematic study of the mechanical properties of nanocomposites constructed by reinforcing an Al matrix with BN and graphene nanoribbons. We consider a simple case of uniform distribution of nanoribbons in an Al matrix under the assumption that such configuration will lead to the maximum enhancement of mechanical characteristics. We estimate the bonding energy and the interfacial critical shear stress at the ribbon/metal interface as functions of ribbon width and show that the introduction of nanoribbons into the metal leads to a substantial increase in the mechanical characteristics of the composite material, as strong covalent bonding between the ribbon edges and Al matrix provides efficient load transfer from the metal to the ribbons. Using the obtained data, we apply the rule of mixtures in order to analytically assess the relationship between the composite strength and concentration of nanoribbons. Finally, we study carbon chains, which can be referred to as the ultimately narrow ribbons, and find that they are not the best fillers due to their weak interaction with the Al matrix. Simulations of the electronic transport properties of the composites with graphene nanoribbons and carbyne chains embedded into Al show that the inclusion of the C phase gives rise to deterioration in the current carrying capacity of the material, but the drop is relatively small, so that the composite material can still transmit current well, if required.
Highlights
Lightweight and mechanically strong materials are of high importance in modern automotive and especially the aerospace industry where even a small reduction of craft weight can give rise to a considerable drop in the operation costs.Nowadays the materials used in this area are mostly based on aluminum, which is a reasonable compromise between the weight, cost and mechanical characteristics, which are far from being impressive for pure Al: its Young’s modulus is about 70 GPa, and tensile strength is 40 MPa only.[1]
We considered the simple case of uniformly distributed nanoribbons embedded into ideal rectangular holes of an Al matrix under the assumption that such distribution and ideal interface between aluminum and nanoribbons will lead to the maximum enhancement of mechanical characteristics
We theoretically studied the possibility of using graphene and h-BN nanoribbons for the reinforcement of Al
Summary
Lightweight and mechanically strong materials are of high importance in modern automotive and especially the aerospace industry where even a small reduction of craft weight can give rise to a considerable drop in the operation costs. It is desirable to find other nanomaterials with comparable mechanical characteristics, but with more reactive surfaces, or optimize the geometry of graphene flakes From such point of view graphene and BN nanoribbons (GNR and BNNR, respectively), in one-dimensional (1D) systems, can be considered as a good choice. We assumed that during the sample preparation the nanoribbons were distributed uniformly and isotropically in the metal matrix, which would lead to the isotropic improvement of the composite mechanical characteristics, and the response of the macroscopic sample to mechanical deformation is governed by the behavior of the fillers under tensile strain, not their bending. EVBias 2 represents the chemical potentials of the left and right electrodes, and T (ε,VBias) is the energy and voltageresolved transmission function
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