Nickel coated carbon nanotubes in aluminum matrix composites: a multiscale simulation study

Abstract

In this work we use density functional theory (DFT) calculations to benchmark empirical potentials for the interaction between nickel and sp 2 bonded carbon nanoparticles. These potentials are then used in order to investigate how Ni decorated or coated carbon nanotubes (CNT) affect the mechanical properties of Al/CNT composites. In particular we look at the pull-out behaviour of pristine as well as Ni-decorated and Ni-coated CNT from an Al matrix. Our result shows that Ni coating may produce an extended interface (interphase) where a significant amount of energy is dissipated during CNT pull-out, leading to a high pull-out force. We also demonstrate that surface decorated CNT may act as efficient nano-crystallization agents and thus provide a novel strengthening mechanism not previously discussed in the literature. We discuss our results in view of promising approaches for engineering CNT-metal interfaces such as to achieve high strength metal-CNT composites. arXiv:1907.05086v1 [cond-mat.mtrl-sci]

Atomistic aspects of load transfer and fracture in CNT-reinforced aluminium

“…In the case of Al reinforced with short CNTs, the composite strength σ p , defined by the highest value of stress reached on the stress-strain curve, is slightly lower than the Al single crystal strength σ Al as shown in Figure 3 decrease in strength. As we observed from our DFT calculations, the interface between Al and CNT is weak -the interface energy is low, and the interface shear strength (IFSS) is of the order of 30 MPa or less [27,28]. Therefore, when the Al-CNT system is loaded in tension, the pristine short CNT aligned parallel to the loading direction can easily slide inside the matrix without carrying a significant part of the applied load.…”

“…In the context of Al-CNT composites, this might happen through carbide formation [61], which, however, needs to be carefully controlled to preserve the structural properties of the CNTs. (iii) An alternative which has been studied in the context of both metal-CNT and polymer-CNT composites consists in non-chemical functionalization of the CNT surface [22,62] which in the context of Al composites might be done by deposition of Ni nanoparticles or coatings [28] or surface decoration by other nanoparticles such as TiC [63].…”

“…For low-melting lightweight metals such as Al or Mg, the benefit of embedding CNTs is still under discussion since these metals do not wet sp 2 bonded carbon nanoparticles. Experimental and simulation studies reported a small value between 24.0 and 35.0 MPa ( [27,28]) for the interfacial shear stress (IFSS) between Al matrix and CNTs, indicating a weak interface between Al and pristine CNTs. Therefore, the immersed CNTs into the Al melt tend to bond to themselves rather than Al atoms and agglomerate.…”

Multilayer Structures of Graphene and Pt Nanoparticles: A Multiscale Computational Study

“…[46] A further possibility is to combine potentials of different type that are separately optimized to describe the energetics and mechanical properties of covalently bonded carbon, and of platinum. A similar approach was used by [47,48] for simulating Ni-graphene interactions: These authors use a standard adaptive intermolecular reactive bond order (AIREBO) potential [46,49] for describing covalent C-C interactions in conjunction with an embedded-atom method (EAM) potential for Ni, and either a LJ potential [47] or a Morse potential [48] for Ni-carbon interactions at the Ni-graphene interface. We emphasize that such addition of structurally dissimilar potentials is, in general, problematic.…”

Link prediction based on the powerful combination of endpoints and neighbors

“…Recently, complex network theory 1 has become an effective tool in the study of various real networks, such as social networks, 2,3 bibliography networks, 4,5 aviation networks, 6,7 and ecological networks. 8,9 However, for the precision of predicting information in complex networks, link prediction technology 10 has obtained more and more attentions from academia and industry.…”