Influence of layer orientation and interlayer bonding force on the mechanical behavior of shale under Brazilian test conditions

The mechanical behavior of inherently anisotropic shale rocks under Brazilian test conditions are investigated in this study based on experimental studies and numerical simulations. The effects of the weak lamination planes and interlayer bonding force of these layers on the failure strength and fracture patterns are studied systematically. Numerical simulations using particle flow code in two dimensions based on the discrete element method showed a good agreement with the experimental results in the failure strength and fracture patterns. The shale revealed strong anisotropic behavior with the failure strength perpendicular to the lamination plane greater than failure strength parallel to lamination plane. The failure strength of the different interlayer bonding force against the layer orientations changed significantly. Four types of fracture patterns were observed: curved fracture, broken-linear fracture, layeractivated fracture, and central-linear fracture. The observed fracture patterns are either or a combination of tensile and/or shear fractures. Increase in interlayer bonding strength decreased the quantity of micro cracks and this directly led to reduction in the anisotropic behavior. Overall the layer orientation and interlayer bonding force of the shale thus play a very important role in the anisotropic behavior of the shale.

Ab initio study of anisotropic mechanical and electronic properties of strained carbon-nitride nanosheet with interlayer bonding

Due to the noticeable structural similarity and being neighborhood in periodic table of group-IV and-V elemental monolayers,whether the combination of group-IV and-V elements could have stable nanosheet structures with optimistic properties has attracted great research interest.In this work,we performed first-principles simulations to investigate the elastic,vibrational and electronic properties of the carbon nitride(CN)nanosheet in the puckered honeycomb structure with covalent interlayer bonding.It has been demonstrated that the structural stability of CN nanosheet is essentially maintained by the strong interlayerσbonding between adjacent carbon atoms in the opposite atomic layers.A negative Poisson’s ratio in the out-of-plane direction under biaxial deformation,and the extreme in-plane stiffness of CN nanosheet,only slightly inferior to the monolayer graphene,are revealed.Moreover,the highly anisotropic mechanical and electronic response of CN nanosheet to tensile strain have been explored.

High mechanical strength Si anode synthesis with interlayer bonded expanded graphite structure for lithium-ion batteries

Despite advancements in silicon-based anodes for high-capacity lithium-ion batteries,their widespread commercial adoption is still hindered by significant volume expansion during cycling,especially at high active mass loadings crucial for practical use.The root of these challenges lies in the mechanical instability of the material,which subsequently leads to the structural failure of the electrode.Here,we present a novel synthesis of a composite combining expanded graphite and silicon nanoparticles.This composite features a unique interlayer-bonded graphite structure,achieved through the application of a modified spark plasma sintering method.Notably,this innovative structure not only facilitates efficient ion and electron transport but also provides exceptional mechanical strength(Vickers hardness:up to658 MPa,Young's modulus:11.6 GPa).This strength effectively accommodates silicon expansion,resulting in an impressive areal capacity of 2.9 mA h cm^(-2)(736 mA h g^(-1)) and a steady cycle life(93% after 100cycles).Such outsta nding performance is paired with features appropriate for large-scale industrial production of silicon batteries,such as active mass loading of at least 3.9 mg cm^(-2),a high-tap density electrode material of 1.68 g cm^(-3)(secondary clusters:1.12 g cm^(-3)),and a production yield of up to 1 kg per day.

Effect of interlayer bonded bilayer graphene on friction

We study the friction properties of interlayer bonded bilayer graphene by simulating the movement of a slider on the surface of bilayer graphene using molecular dynamics.The results show that the presence of the interlayer covalent bonds due to the local sp^(3) hybridization of carbon atoms in the bilayer graphene seriously reduces the frictional coefficient of the bilayer graphene surface to 30%,depending on the coverage of interlayer sp^(3) bonds and normal loads.For a certain coverage of interlayer sp3bonds,when the normal load of the slider reaches a certain value,the surface of this interlayer bonded bilayer graphene will lose the friction reduction effect on the slider.Our findings provide guidance for the regulation and manipulation of the frictional properties of bilayer graphene surfaces through interlayer covalent bonds,which may be useful for applications of friction related graphene based nanodevices.

An Experimental Study on Assessment of Pavement Interlayer Bond Strength

It is a common practice to apply a tack coat usually in the form of bituminous emulsion over an existing bituminous surface before laying another bituminous layer.The boundary between these two consecutive bituminous layers is the layer interface and the pavement stress distribution is highly influenced by the adhesion conditions at this interface.Poor adhesion causes adverse effects on the structural strength of the pavement system.A number of premature failures such as slippage failure and delamination failures result thus defeating the construction objectives.In the absence of a standard method and apparatus to address this field problem,an attempt has been made in this study to develop a simple testing arrangement to be used in a laboratory to determine the interlayer bond strength.Normal Marshall procedure has been used to prepare the specimens consisting of two different types of bituminous materials in lower and upper part of the same specimen.It is observed within the scope of study that Cationic rapid setting(CRS-1)emulsion applied at 0.25 Kg/m^(2) offers the best results of interlayer bond strength.

Characterization of bonding property in asphalt pavement interlayer: A review

Higher requirements are put forward for interlayer bonding property with the increase of traffic load, including bearing capacity and durability. Typical diseases caused by insufficient adhesion between layers are slippage cracking, de-bonding and pavement deformation. The correct characterization of bonding property becomes necessary with evolving concerns of interlayer failure and material innovations. In the past forty years, many researches have focused on the evaluation of interlayer bonding property, and some valuable conclusions have been drawn. In this review, the mechanism, evaluation method and influencing factors of the interlayer bond strength are reviewed. The common test equipment can be classified into the shear, pull-off and torsion test. Different influence factors are analyzed including tack coat property, temperature, asphalt aging and surface condition. It is recommended to select the appropriate tack coat rate, and apply the tack coat under the conditions of clean, dry, high surface texture and good compaction. However, the interlayer failure mechanism and the interaction between the different influencing factors need to be further studied. The future work can focus on the correlation between different test methods and evaluation parameters, which would address the lack of harmonization or consistency among various evaluation approaches. Meanwhile, it is significant to add the evaluation of interlayer bonding property into the system of pavement design.

Molecular Scaffold Growth of Two-Dimensional, Strong Interlayer-Bonding-Layered Materials

Currently,most two-dimensional(2D)materials that are of interest to emergent applications have focused on van der Waals–layered materials(VLMs)because of the ease with which the layers can be separated(e.g.,graphene).Strong interlayer-bonding-layered materials(SLMs)in general have not been thoroughly explored,and one of the most critical present issues is the huge challenge of their preparation,although their physicochemical proper-ty transformation should be richer than VLMs and deserves greater attention.MAX phases are a classi-cal kind of SLM.

Interfacial Microstructure and Properties of Ti(C, N)/Ni Bonded by Transient Liquid-phase Diffusion

Effects of the main process parameters（temperature and time） on microstructure and properties of Ti（C, N）/Ni interface bonded by （Cu＋Nb） interlayer in a vacuum diffusion bonding device were investigated. The interfacial microstructures consisted initially of Ni3Nb metallic compound and eutectic of Ni3Nb ＋ CuNiss, and finally transformed to （Ti, Nb） （C, N）＋Ni3Nb near Ti （C, N） and NiCuss ＋ Ni3Nb near Ni when diffusion bonding temperature was 1 523-1 573 K. It was clear that Cu was a constituent in the transient liquid phase （TLP） into which Ni was dissolved by forming Cu-Ni transition liquid. Nb was dissolved in Cu-Ni transition liquid rapidly. Ti （C, N） conld be wetted by resultant Ni-Nb-Cu transient liquid phase which was followed by a little （Ti, Nb） （C, N） solid solution formed at interface. This increased the interface combining capability. Ultimately the interface shear strength was able to reach 140 MPa. The theoretle analysis and experimental results show that the growth of interfacial reaction layer Ni3Nb accords with parabola law, and the activation energy of diffusion reaction is 115.0±0.5 kJ/mol, while the diffusion reaction speed constant is 12.53 mm/s^1/2.

Local probe of the interlayer coupling strength of few-layers SnSe by contact-resonance atomic force microscopy

The interlayer bonding in two-dimensional(2D)materials is particularly important because it is not only related to their physical and chemical stability but also afects their mechanical,thermal,elec-tronic,optical,and other properties.To address this issue,we report the direct characterization of the interlayer bonding in 2D SnSe using contact-resonance atomic force microscopy(CR-AFM)in.this study.Site-specific CR spectroscopy and CR force spectroscopy measurements are performed on both SnSe and its supporting SiO2/Si substrate comparatively.Based on the cantilever and contact mechanic models,the contact stifness and vertical Young's modulus are evaluated in comparison with SiO2/Si as a reference material.The interlayer bonding of SnSe is further analyzed in combination with the semi-analytical model and density functional theory calculations.The direct characteriza-tion of interlayer interactions using this non-destructive methodology of CR-AFM would facilitate a better understanding of the physical and chemical properties of 2D layered materials,specifically for interlayer intercalation and vertical heterostructures.