Bonding properties of interface in Fe/Al clad tube prepared by explosive welding

A Fe/Al clad tube was prepared by explosive welding.Then the bonding characteristic of the interface was investigated by compression,flattening and compression-shear test.The test results exhibit that the clad tubes possessing good bonding interface have higher shear strength than that of pure aluminum and can bear both axial and radial deformation.The original interface between aluminum layer and ferrite layer was observed by scanning electron microscopy（SEM）.The results show that the clad tubes with good bonding properties possess the interface in wave and straight shape.The Fe/Al clad tube was used to manufacture the T-shape by hydro-bulging.It is found that the good-bonding interface of the Fe/Al clad tube plays a dominant role in the formation of the T-shape.

Effect of neutral polymeric bonding agent on tensile mechanical properties and damage evolution of NEPE propellant

Introducing Neutral Polymeric bonding agents(NPBA) into the Nitrate Ester Plasticized Polyether(NEPE)propellant could improve the adhesion between filler/matrix interface, thereby contributing to the development of new generations of the NEPE propellant with better mechanical properties. Therefore,understanding the effects of NPBA on the deformation and damage evolution of the NEPE propellant is fundamental to material design and applications. This paper studies the uniaxial tensile and stress relaxation responses of the NEPE propellant with different amounts of NPBA. The damage evolution in terms of interface debonding is further investigated using a cohesive-zone model(CZM). Experimental results show that the initial modulus and strength of the NEPE propellant increase with the increasing amount of NPBA while the elongation decreases. Meanwhile, the relaxation rate slows down and a higher long-term equilibrium modulus is reached. Experimental and numerical analyses indicate that interface debonding and crack propagation along filler-matrix interface are the dominant damage mechanism for the samples with a low amount of NPBA, while damage localization and crack advancement through the matrix are predominant for the ones with a high amount of NPBA. Finally, crosslinking density tests and simulation results also show that the effect of the bonding agent is interfacial rather than due to the overall crosslinking density change of the binder.

Liquid-solid interface control of BFe10-1-1 cupronickel alloy tubes during HCCM horizontal continuous casting and its effect on the microstructure and properties

Based on horizontal continuous casting with a heating-cooling combined mold （HCCM） technology, this article investigated the effects of processing parameters on the liquid-solid interface （LSI） position and the influence of LSI position on the surface quality, microstructure, texture, and mechanical properties of a BFe10-1-1 tube （φ50 mm × 5 mm）. HCCM efficiently improves the temperature gradient in front of the LSI. Through controlling the LSI position, the radial columnar-grained microstructure that is commonly generated by cooling mold casting can be eliminated, and the axial columnar-grained microstructure can be obtained. Under the condition of 1250℃ melting and holding temperature, 1200-1250℃ mold heating temperature, 50-80 mm/min mean drawing speed, and 500-700 L/h cooling water flow rate, the LSI position is located at the middle of the transition zone or near the entrance of the cooling section, and the as-cast tube not only has a strong axial columnar-grained microstructure （{hkl}〈621〉, {hkl}〈221〉） due to strong axial heating conduction during solidification but also has smooth internal and external surfaces without cracks, scratches, and other macroscopic defects due to short solidified shell length and short contact length between the tube and the mold at high temperature. The elongation and tensile strength of the tube are 46.0%-47.2% and 210-221 MPa, respectively, which can be directly used for the subsequent cold-large-strain processing.

Comparative study on the interface and mechanical properties of T700/Al and M40/Al composites

T700/Al and M40/Al composites were fabricated by squeeze casting technology, and their interface and mechanical properties were investigated comparatively. The results showed that both of the composites were dense, and the fibers were distributed uniformly in aluminum matrix. Aluminum carbide （Al4C3） was observed on the interface of the two carbon fiber-reinforced aluminum （Cf/Al） composites. There was little Al4C3 with a length of 300-500 nm and a width of 30-60 nm in the M40/Al composite, whereas there was a great deal of Al4C3 with a length of 200-400 nm and a width of 100-200 nm in the T700/Al composite, due to a higher graphitization of M40Cf than T700Cf. The M40/Al composite showed a much higher tensile strength than the TT00/Al composite, and it was related to interracial bonding between carbon fibers and aluminum matrices.

Effect of interface morphology on the mechanical properties of titanium clad steel plates

Interface morphology has important influence on the bond quality of titanium clad steel plates. The mechanical properties of titanium clad steel plates with wavy and straight interfaces were investigated by tensile-shear tests and bending tests. The interface morphology of the plates was examined by optical microscopy （OM） and scanning electron microscopy （SEM）. The experimental results show that the shear strength of a wavy interface is higher than that of a straight interface. A wavy interface is the guarantee for obtaining high shear strength to provide a greater shear resistance. During the maerobending process, cracks appear in the swirl of the wave tip and ferrotitanium intermetallies. For in-situ observing the bending process by SEM, the wave tip of a wavy interface and the massive ferrotitartium intermetallies of a straight interface are places where cracks initiate and propagate. The results are the same as those observed in the macrobending process. Became of high hardness, the wave tip and the massive ferrotitanium intermetallies are hard in terms of compatible deformation.

Mechanical properties and friction-wear characteristics of VN/Ag multilayer coatings with heterogeneous and transition interfaces

The heterogeneous multilayer interface of VN/Ag coatings and transition multilayer interface of VN/Ag coatings were prepared on Inconel 781 and Si(100),and the microstructures,mechanical and tribological properties were investigated from 25 to 700℃.The results showed that the surface roughness and average grain size of VN/Ag coatings with transition multilayer interface are obviously larger than those of VN/Ag coatings with heterogeneous multilayer interface.The coatings with transition multilayer interface have higher adhesion force and hardness than the coatings with heterogeneous multilayer interface,and both coatings can effectively restrict the initiation and propagation of microcracks.Both coatings have excellent self-adaptive lubricating properties with a decrease of friction coefficient as the temperature increases,but their wear rates reveal a drastic increase.The phase composition of the worn area of both coatings was investigated,which indicates that a smooth Ag,Magnéli phase(V2O5)and bimetallic oxides(Ag3VO4 and AgVO3)can be responsible to the excellent lubricity of both coatings.To sum up,the coatings with transition multilayer interface have excellent adaptive lubricating properties and can properly control the diffusion rate and release rate of the lubricating phase,indicating that they have great potential in solving the problem of friction and wear of mechanical parts.

Studying the mechanical properties of the soil-root interface using the pullout test method

It is important to quantify the effect of the root diameter, the embedment length of the root and load speed on the soil-root interface mechanical properties for studying the root anchorage. The soilroot interface mechanical properties can be obtained through the pullout force and root slippage curve(F-S curve). About 120 Pinus tabulaeformis single roots whose diameters ranged from 1 mm to 10 mm divided into 6 groups based on different root embedment length(50 mm, 100 mm and 150 mm) and different load velocity(10 mm·min^(-1), 50 mm·min^(-1), 100 mm·min^(-1) and 300 mm·min^(-1)) were investigated using the pullout method. This study aims to explore the mechanical properties of the soil-root interface in the real conditions using the pullout test method. The results showed two kinds of pullout test failure modes during the experimental process: breakage failure and pullout failure. The results showed that the roots were easier to be broken when the root diameter was smaller or the loading speed was larger. The relationship between the maximum anchorage force and root diameter was linear and the linearly dependent coefficient(R^2) was larger than 0.85. The anchorage force increased with the root embedment length. An increase of 10%^(-1)5% for the maximumanchorage force was found when load speed increased from 10 to 300 mm.min^(-1). The mean peak slippage of the root was from 13.81 to 35.79 mm when the load velocity varied from 10 to 300 mm.min^(-1). The study will be helpful for the design of slopes reinforced by vegetation and in predicting risk of uprooting of trees, and will have practical benefits for understanding the mechanism of landslide.

Experimental study on the shear behavior of grout-infilled specimens and micromechanical properties of grout-rock interface

The grout-rock interfacial property is one of the key factors associated with the strength of grouted rock masses.In this study,direct shear tests and nanoindentation tests were adopted to investigate the mechanical properties of the grout-rock interface at both the macroscale and microscale.The cohesion of the cement specimens was higher than that of the grout-infilled joint specimens,while their internal friction angle was lower than that of the grout-infilled joint specimens.A“separation method”for identifying the different phases according to the qualitative and quantitative estimations was introduced,and the irregular interfacial transition zone(ITZ)thickness and elastic modulus were estimated.The ITZ thickness of the grout-infilled sandstone specimen ranged from 0 to 30μm,whereas it was within the range of 10-40μm for the grout-infilled mudstone specimen.The average elastic modulus of the ITZ in grout-infilled sandstone and mudstone specimens was approximately 58.2%and 54.1%lower than that of the bulk grout,respectively.Regarding the incidence of the rock type,the interlacing between the grout and sandstone was better developed.The ITZ with a higher porosity and lower modulus had a significant effect on the mechanical properties of the grout-infilled specimens.

Tight Focusing Properties of Azimuthally Polarized Pair of Vortex Beams through a Dielectric Interface

Tight focusing properties of an azimuthally polarized Gaussian beam with a pair of vortices through a dielectric interface is theoretically investigated by vector diffraction theory. For the incident beam with a pair of vortices of opposite topological charges, the vortices move toward each other, annihilate and revive in the vicinity of focal plane, which results in the generation of many novel focal patterns. The usable focal structures generated through the tight focusing of the double-vortex beams may find applications in micro-particle trapping, manipulation, and material processing, etc.

INTERFACE AND PROPERTIES OF ALKALI-TREATED CARBON FIBRE REINFORCED CEMENT COMPOSITES

The surface of carbon fibre is studied which has been treated with heated sodium hydrate solution (NaOH) . It is found that the surface of carbon fibre is not corroded during the treatment. But at the same time, it is also found that after this treatment, a certain number of carbonyl groups (C O) and (-COOH or ?COONa) are produced on the treated surface of carbon fibre. When carbon fiber is mixed with cement paste, the above reactive groups will link with Ca+2 in the paste, which will result in an early stage hydration of cement in inter facial areas. In addition, the experiments show that the rheological properties of cement paste reinforced with alkali-treated carbon fibre differ greatly from that of untreated carbon fibre reinforced cement paste.

Three-and two-dimensional calculations for the interface anisotropy dependence of magnetic properties of exchange-spring Nd2Fe(14)B/α-Fe multilayers with out-of-plane easy axes

Hysteresis loops,energy products and magnetic moment distributions of perpendicularly oriented Nd2Fe(14)B/α-Fe exchange-spring multilayers are studied systematically based on both three-dimensional(3D)and one-dimensional(1D)micromagnetic methods,focused on the influence of the interface anisotropy.The calculated results are carefully compared with each other.The interface anisotropy effect is very palpable on the nucleation,pinning and coercive fields when the soft layer is very thin.However,as the soft layer thickness increases,the pinning and coercive fields are almost unchanged with the increment of interface anisotropy though the nucleation field still monotonically rises.Negative interface anisotropy decreases the maximum energy products and increases slightly the angles between the magnetization and applied field.The magnetic moment distributions in the thickness direction at various applied fields demonstrate a progress of three-step magnetic reversal,i.e.,nucleation,evolution and irreversible motion of the domain wall.The above results calculated by two models are in good agreement with each other.Moreover,the in-plane magnetic moment orientations based on two models are different.The 3D calculation shows a progress of generation and disappearance of vortex state,however,the magnetization orientations within the film plane calculated by the 1D model are coherent.Simulation results suggest that negative interface anisotropy is necessarily avoided experimentally.

The interface density dependence of the electrical properties of 0.9Pb(Sc_(0.5)Ta_(0.5))O_3–0.1PbTiO_3/0.55Pb(Sc_(0.5)Ta_(0.5))O_3–0.45PbTiO_3 multilayer thin films

The 0.9Pb（Sc0.5Ta0.5）O3-0.1PbTiO3/0.55Pb（Sc0.5Ta0.5）O3-0.45 PbTiO3 multilayer thin films（（PSTT10/45）n, n = 1-6, 10） are deposited on SiO2/Si（100） substrates by radio frequency magnetron sputtering technique with La Ni O3 buffer and electrode layer, and the films are subsequently annealed by a two-step rapid thermal approach. It is found that the interfacial density of the film has an important influence on the electric property of the film. The electric property of the film increases and reaches its critical point with the increase of interface density, and then decreases with the further increase of the interface density. With an interfacial density of 16 μm-1, the film shows an optimized dielectric property（high dielectric constant, εr = 765, lowest dielectric loss, tan δ = 0.041, at 1 k Hz） and ferroelectric property（highest remnant polarization,2Pr = 36.9 μC/cm2, low coercive field, 2Ec = 71.9 k V/cm）. The possible reason for the electric behavior of the film is the competition of the interface stress with the interface defect.

MICROSTRUCTURE，INTERFACE AND MECHANICAL PROPERTIES OF NiAl－BASED COMPOSITES REINFORCED BY TiB_2 PARTICULATES

This paper developed a hot Pressing aided exothermic synthesis (HPES) technique. to fabricate NiAl matrix composites containing 0 and 20 v.% TiB_2 particles. The conversion to the product was complete. and TiB_2 particles in the matrix were uniformly dispersed. The inter faces between nail and TiB_2 were atomically flat. sharp and free from any inter facial phases in most cases. In some cases. however. thin inter facial amorphous layers existed at NiAl/ TiB_2 interfaces. In addition, the microstructure and inter faces were highly thermal stable. In all processing states. the yield strengths at room temperature or at 1000℃ of the composite were approximately three times as strong as that of the unrein forced NiAl. The ambient fracture toughness of the composite was also superior to monolithic NiAl.

STRUCTURE AND INTERFACE PROPERTIES OF Fe/C MULTILAYERS

Fe/C multilayer thin films were deposited by magnetron sputtering. Small angle X-ray diffraction measurements show very well periodicity of the samples. The modulation period determined from a modified Bragg equation agrees well with that determined from deposition rate. The interfacial roughness parameter ξof several samples calculated by X-ray diffraction is between 3.5(?) and 5.6(?).

Optical Properties of the Coupling Interface for Planar Optical Waveguides

Planar optical waveguides are the key elements in a modern, high-speed optical network. An important problem facing the optical fiber communication system, specifically planar optical waveguides, is coupling. The current study presents a coupling model for planar optical waveguides and optical fibers. The various effects of the optical properties of the coupling interface were analyzed by the scalar finite difference beam propagation method, including the thickness, with or without the matching refractive index of the interface adhesive. The findings can serve as a guide for planar optical waveguide packaging.

Effect of PyC Interface Thickness on the Heat-stability of Cansas-ⅡSiC_(f)/SiC Composites

The effect of the pyrolytic carbon(PyC)interface thickness on the heat-stability of CansasⅡSiC_(f)/SiC composites under Ar up to 1500℃was studied in detail.After the heat treatment at 1500℃for 50 h,the interface bonding strength of the thin interface(about 200 nm)decreases from 74.4 to 20.1 MPa(73.0%),while that of the thick interface(about 2μm)declines from 7.3 to 3.2 MPa(52.7%).At the same time,the decline fraction of strength of the composites with the thin interface is 12.1%,less than that with the thick interface(42.0%).The fiber strength also decreases after heat treatment,which may be due to the significant growth ofβ-SiC grains and critical defects.The different heat-stability of the interface with the thin and thick thickness might be related to the inconsistency of the degree of the graphitization of PyC.Compared with the composites with the thick interface,the composites with the thin interface remained higher tensile strength after heat treatment due to the better interface bonding strength.The interface with strong bonding strength could protect the fiber by postponing the decomposition of amorphous phases SiC_(x)O_(y) and hindering the generation of fiber defects.

Influence of Ni interlayer on interfacial microstructure and mechanical properties of Ti-6Al-4V/AZ91D bimetals fabricated by a solid–liquid compound casting process

The solid–liquid compound casting of Mg-AZ91D and Ti-TC4 alloys was developed by using pure Ni electro-deposited coating.The pouring temperatures of 660℃,690℃,720℃and 750℃were chosen to investigated the effects of casting temperatures on microstructural evolution,properties,and fracture behaviors of Ni-coated TC4/AZ91D bimetals by the solid–liquid compound casting(SLCC).The scanning electron microscopy(SEM)and the energy dispersive spectroscopy(EDS)results showed that the interfacial zone mainly composed of nickel,Mg_(2)Ni and Mg-Al-Ni in the bimetals cast at 660℃.As the pouring temperature was increased to 750℃,the width of the interface zone,which mainly composed ofδ(Mg),Mg_(2)Ni,Mg-Al-Ni,Mg_(3)TiNi_(2) and Al_(3)Ni,gradually increased.The microhardness tests showed that the micro-hardness of the interface zone was smaller than that of TC4 substrate but larger than that of the cast AZ91D matrix.At the pouring temperature of 720℃,the Ni-coated TC4/AZ91D bimetals had the most typical homogeneous interface,which had granular Mg-Al-Ni ternary phase but no ribbon-like Al3Ni binary phase,and achieved the highest shear strength of 97.35MPa.Meanwhile,further fracture behavior analysis showed that most fracture failure of Ni-coated TC4/AZ91D bimetals occurred at the Mg_(2)Ni+δ(Mg)eutectic structure and Al_(3)Ni hard intermetallic.

A review of processing of Cu/C base plate composites for interfacial control and improved properties

The increase in both power and packing densities in power electronic devices has led to an increase in the market demand for effective heat-dissipating materials with a high thermal conductivity and thermal expansion coefficient compatible with chip materials while still ensuring the reliability of the power modules.Metal matrix composites,especially copper matrix composites,containing carbon fibers,carbon nanofibers,or diamond are considered very promising as the next generation of thermalmanagement materials in power electronic packages.These composites exhibit enhanced thermal properties,as compared to pure copper,combined with lower density.This paper presents powder metallurgy and hot uniaxial pressing fabrication techniques for copper/carbon composite materials which promise to be efficient heat-dissipation materials for power electronic modules.Thermal analyses clearly indicate that interfacial treatments are required in these composites to achieve high thermal and thermomechanical properties.Control of interfaces(through a novel reinforcement surface treatment,the addition of a carbide-forming element inside the copper powders,and processing methods),when selected carefully and processed properly,will form the right chemical/mechanical bonding between copper and carbon,enhancing all of the desired thermal and thermomechanical properties while minimizing the deleterious effects.This paper outlines a variety of methods and interfacial materials that achieve these goals.

The enhanced mechanical properties of SiC nanowires/Ba0.75Sr0.25Al2Si2O8 ceramics with embedded SiO2 interface

In this work,low-softening-temperature and low-modulus SiO2 was introduced as an embedded interface between SiC nanowires(SiCnws)and a BaxSr1−xAl2Si2O8 ceramic matrix to enhance strength and toughness of the ceramic.During the sintering process,molten SiO2 enhances the flowability of the ceramic powders and modifies the dispersion of SiCnws.The strengthening effect of SiCnws was fully realized,and the flexural strength of the optimized ceramics reached 193±16 MPa,which represents an increase of 52.6%.After the formation of the embedded SiO2 interface with a low modulus,cracks can deflect along the SiCnws surface,which is consistent with the criterion of He and Hutchinson.This can effectively extend the crack propagation path,and the fracture toughness(K_(IC))is thus improved by 94.0%,reaching 3.1±0.5 MPa·m^(1/2).

EFFECT 0F INTERFACIAL ADHESION ON CRYSTALLIZATION AND MECHANICAL PROPERTIES OF POLY (ETHYLENE TEREPHTHALATE)/GLASS BEAD COMPOSITES

The interfacial adhesion between poly (ethylene terephthalate) (PET) and glass beadwas investigated by scanning electron microscope and parallel-plate rheometer. Effect ofinterfacial adhesion on the crystallization and mechenical properties of PET/glass beadcomposites was also studied by differential scanning calorimeter and mechanical testers.The results obtained indicate that the glass bead has a heterogeneous nucleation effecton the PET crystallization. Although better interfacial adhesion is advantageous to theincrease of the tensile strength of the composite, yet it is unfavorable to the crystallizationof PET. It should be pointed out that the crystallization rate of filled PET is always higherthan that of pure PET, regardless of the state of interfacial adhesion.