Metal Cladding Research Articles

Hot corrosion behavior of Cr-modified NiAl coatings on 310 stainless steel produced by a gas tungsten arc cladding process

The microstructure and hot corrosion behavior of Ni/Al–Cr composite claddings produced by gas tungsten arc welding (GTAW) on a 310 stainless steel substrate were studied. The phase analyses and the microstructure of the cladding layers were evaluated using optical microscopy, X-ray diffraction (XRD) and scanning electron microscopy. The influence of Cr addition (0, 5, 10 at% Cr) on the microstructure and hot corrosion behavior of the NiAl coatings was assessed. The cyclic hot corrosion behavior of the base metal and different claddings was investigated at 900°C and in static air, with a 2–3 mg/cm2 Na2SO4–10%NaCl (wt%). It was found that a dendritic microstructure was formed on the clad surfaces. The results of the XRD analyses indicated that a NiAl phase was synthesized in situ during GTAW cladding and the presence of Cr reduced the intensity of diffraction peaks of NiAl. Hot corrosion experiments also revealed that the addition of Cr had a crucial influence on the hot corrosion behavior of NiAl coatings. It was found that the larger the amount of Cr, the superior the resistance of the coatings to hot corrosion. This improvement was attributed to the formation of Al2O3 as a protective oxide layer, as evidenced by XRD patterns. However, the iron containing phases produced as a result of interactions with the substrate were found to be a detrimental factor influencing the corrosion properties of different cladded layers.

Analysis and Investigation of Slow Light Based on Plasmonic Induced Transparency in Metal-Dielectric-Metal Ring Resonator in a Waveguide System with Different Geometrical Designs

In this paper we will try to create, propose and analyze structure of a slow light device, based on plasmonic induced transparency in a metal-dielectric-metal based ring resonator. Group index by first design about 37 and second design about 35 earned. The proposed dielectric material is Poly Methyl Meta Acrylate (PMMA) sandwiched by gold metal cladding. Finite Element Method-con- ducted Electromagnetic simulations are employed to evaluate the plasmonic designs for behavior of slow light. The signal and pump wavelength are assumed to be 830 nm and 1550 nm respectively in the systems. The overall length of the plasmonic slow light system is 600 nm. In a wide range of frequency bands, the optical properties of metals can be described with a plasma model. The optical signal can be achieved with the use of surface waves on the boundary between the insulating materials and metals with dimensions smaller than the diffraction limit. The main goal, is estimation of optical characteristics such as bandwidth, the Real and Imaginary parts of refractive index, group velocity and slow down factor in such optical devices. The obtained results and observations, can be useful in basic research and the production of highly integrated plasmonic devices.

Analysis of a metal clad waveguide sensor having metamaterial as a guiding layer

AbstractIn this study a metal clad waveguide sensor with a metamaterial guiding layer is analyzed. Sensitivity of the proposed sensor is derived using dispersion and Fresenal’s equations for waveguiding mode and reflection mode. While efficiently analyzing and comparing the results with the existing one, some interesting findings are achieved. It is observed that the proposed sensor shows larger cover layer sensitivity and larger adlayer sensitivity compared to the dielectric guiding layer sensor due to adsorbtive properties of metamaterial. Henceforth, it concludes that the proposed sensor shows sensitivity improvement over a dielectric guiding layer sensor.

Plasmon-Induced Transparency in a Surface Plasmon Polariton Waveguide with a Right-Angled Slot and Rectangle Cavity

The phenomenon of plasmon-induced transparency (PIT) is realized a in surface plasmon polariton waveguide at near-infrared frequencies. The right-angled slot and rectangle cavity placed inside one of the metallic claddings are respectively utilized to obtain bright and dark modes in a typical bright-dark mode waveguide. A PIT transmission spectrum of the waveguide is generated due to the destructive interference between the bright and dark modes, and the induced transparency peak can be manipulated by adjusting the size of the bright and dark resonators and the coupling distance between them. Subsequently, spectral splitting based on the PIT structure is studied numerically and analytically. Simulation results indicate that double electromagnetically induced transparency (EIT)-like peaks emerge in the broadband transmission spectrum by adding another rectangle cavity, and the corresponding physical mechanism is presented. Our novel plasmonic structure and the findings pave the way for new design and engineering of highly integrated optical circuit such as nanoscale optical switching, nanosensor, and wavelength-selecting nanostructure.

Effects of elevated temperatures on the mechanical properties of nickel-based alloy clad pipelines girth welds

Tensile and fracture tests were performed on nickel-based alloy clad pipelines girth welds using customised rigs to elevate the temperature. Fracture tests were performed using single edged notched bend (SENB) and single edged notched tension (SENT) specimens, both with notch depth ratio of 0.2. The tensile test results showed reduction in strength at elevated temperatures for base metal, weld metal and clad metal while the fracture resistance reduced by up to 0.6 times depending on the notch location and the specimen geometry. The SENT specimens exhibited a higher fracture resistance than the SENB specimens, with an increase by about 1.3 times.

Design optimization of long period waveguide grating devices for refractive index sensing using adaptive particle swarm optimization

Grating assisted surface plasmon resonance waveguide grating has been designed and optimized for the sensing application. Adaptive particle swarm optimization in conjunction with derivative free method for mode computation has been used for design optimization of LPWG sensor. Effect of metal thickness and cladding layer thickness on the core mode and surface plasmon mode has been analyzed in detail. Results have been utilized as benchmarks for deciding the bounds of these variables in the optimization process. Two waveguides structures have been demonstrated for the grating assisted surface plasmon resonance refractive index sensor. The sensitivity of the designed sensors has been achieved 3.5×104nm/RIU and 5.0×104nm/RIU with optimized waveguide and grating parameters.

SiC 복합체 보호막 금속 피복관의 개발 및 고온산화 특성 분석

The goal of this study is to investigate a metal cladding that contains SiC composites as a protective layer and analysis the characteristics of the specimens on high temperature oxidation To make SiC composites, the current process needs a high temperature (about <TEX>$1100^{\circ}C$</TEX>) for the infiltration of fixing materials such as SiC. To improve this situation, we need a low temperature process. In this study, we developed a low temperature process for making SiC composites on the metal layer, and we have made two kinds: cladding with protective SiC composites made by polycarbosilane(PCS), and a PCS filling method using supercritical carbon dioxide. A corrosion test at <TEX>$1200^{\circ}C$</TEX> in a mixed steam and Ar atmosphere was performed on these specimens. The result show that the cladding with protective SiC composites have excellent oxidation suprression rates. This study can be said to have developed new metal cladding with enhanced durability by using SiC composite as protective films of metal cladding instead of simple coating film.

Synthesis of Tensor Impedance Surfaces to Control Phase and Power Flow of Guided Waves

A synthesis method for printed-circuit tensor impedance surfaces (PCTISs) is presented that allows arbitrary control of phase progression and power flow of guided waves. PCTISs consist of a subwavelength-patterned metallic cladding atop a grounded dielectric substrate. The cladding is modeled by an anisotropic tensor sheet admittance. The synthesis method employs field analysis to determine the required tensor sheet admittance values for a prescribed phase progression and power-flow direction. An inhomogeneous distribution of PCTIS unit cells can be used to design a 2-D metasurface capable of spatial control of surface waves. A collimator is designed to verify the proposed synthesis procedure and demonstrate its utility.

Investigation of Microstructure and Mechanical Properties of St37 Steel-Ck60 Steel Joints by Explosive Cladding

The present work aimed at studying the microstructure and mechanical properties of Ck60/St37 composite plates fabricated by explosive cladding. The explosive ratio and stand-off distance were set to be R = 1.7 and s = 1.5t, respectively. Optical and scanning electron microscopy revealed that the bonding at the interface had a wavy morphology, but local melted zones were formed along the interface. The chemical composition of the local melted zones was evaluated by energy-dispersive spectroscopy analysis. This analysis showed that the melted zones consisted of both Ck60 and St37 steels. The maximum hardness was obtained near the explosively cladded interface; then these values were decreased by the distance away from the interface. Moreover, it was seen that the local melted zones, especially the vortices, had a high degree of hardness. Shear tests on the cladded metals also showed that the average shear strength was higher than 140 MPa, as set by the ASTM A263-12, implying that composite plates could be used safely. The study was also conducted to consider the strength of bonding by bending test in two ways, one with the cladding metal in tension and the other with the cladding metal in compression. Bending test results showed that these joints could be used safely when the cladded metal was in compression; otherwise, it would be fractured. Finally, impact test results showed that the fracture toughness of cladded samples was higher than that of flyer material due to the higher fracture toughness of the base material.

Superscattering-enhanced narrow band forward scattering antenna**Project supported by the National Natural Science Foundation of China (Grant No. 61377054), the Collaborative Innovation Foundation of Sichuan University, China (Grant No. XTCX 2013002), and the International Cooperation and Exchange of Science and Technology Project in Sichuan Province, China (Grant No. 2013HH0010).

We present a narrow band forward scattering optical antenna which is based on the excitation of distinctive whispering gallery modes (WGMs). The antenna is composed of three coaxial cylinder layers: a dielectric layer is sandwiched between a metallic core and cladding. Owing to the destructive interference between the scattering of the outer metallic cladding and the WGM in the backward direction, the power flow in the forward direction is increased. Simulation and analysis show that in proper geometry conditions, the cavity can be tuned into a superscattering state. At this state, both the zeroth and the first order of WGM are excited and contribute to the total scattering. It is shown that the power ratio (power towards backward divided by power towards forward) can be enhanced to about 27 times larger than that for a non-resonant position by the superscattering. Owing to the confinement of the cladding to WGMs, the wavelength range of effective forward scattering is considerably narrow (about 15 nm).

Effect of Heat Input on Intergranular Corrosion Resistance of Duplex Stainless Steel Clad Metals

Effect of Heat Input on Intergranular Corrosion Resistance of Duplex Stainless Steel Clad Metals

Effect of Heat Input on Intergranular Corrosion Resistance of Duplex Stainless Steel Clad Metals

Effect of Heat Input on Intergranular Corrosion Resistance of Duplex Stainless Steel Clad Metals

Analytical and experimental analysis of the formability of copper-stainless-steel 304L clad metal sheets in deep drawing

The formability of the clad metal sheets is influenced by many factors such as mechanical properties of the component metals, so that producing clad cups with high formability free of defects is not easily possible. The behavior of clad sheet, vis-a-vis single-layer sheets, is comprehensively studied through experimental as well as numerical methods using the finite element analysis. In this study, the limiting draw ratio and thickness variations of copper-stainless-steel 304L clad metal sheet have been investigated. Finite element simulations were conducted to study the process and to predict the fracture position. The experimental results in various conditions were compared and the desirable state was recognized. Results illustrated that the thickness distribution of stronger material (stainless-steel 304L) was somewhat more uniform than the weaker one (copper layer). It is demonstrated that the strain distributions in the deep-drawn cups obtained by the FE method can be used to predict the location of fracture in the experimental tests. Furthermore, it was found that the formability of clad sheets, in different layout settings, with respect to various parameters, followed the same trends as single-layer sheets.

Study on the symmetrical metal-cladding waveguide-enhanced quality factor

The quality factor (Q value) is a vital parameter for evaluating the sensitivity feature of optical sensors. A comparative study of Q values is carried out by analyzing the absorption peaks of the attenuated total reflection in the surface plasmon resonance, long-range surface plasmon resonance, metal clad leaky waveguide, and symmetrical metal-cladding waveguide. The calculation results show that the full width at half maximum of the ultrahigh-order modes, which are excited in the SMCW, can be reduced to the order of 10−2 nm, and the corresponding Q value can be enhanced to the order of 104, which is far beyond those of other sensing structures.

Mechanical Performance and Ductility of Cu/Al/Cu Clad Metals

The tensile mechanical performance and ductility of Cu/Al/Cu clad composite were studied. Brittle interfacial reaction compounds were observed at Cu/Al interfaces after annealing at 500°C. The ultimate tensile strength of the tri-layered Cu/Al/Cu clad plates is in close agreement with those calculated from the UTS data of separated Cu and Al layers using the rule of mixture. The loss of ductility in Cu/Al/Cu and separate Cu upon annealing at 500°C is associated with the brittle intermetallic layer. The greater ductility of as-roll-bonded Cu/Al/Cu than those of both Cu and Al is linked to the excellent interface bonding after roll-bonding. Excellent bonding at Cu/Al interface is prerequisites for improvement ductility of clad composite.

Sensitivity enhancement of metal clad planar waveguide sensor using metamaterial layer as a guiding layer

In the present paper, a comprehensive study of sensitivity and reflectance of metal clad planar waveguide biosensor having metamaterial in guiding layer has been done. The sensitivity and reflectivity of proposed waveguide sensor are calculated using Fresnel's laws. It is observed that the sensitivity of a waveguide is highly affected by the presence of metamaterial layer. The calculated sensitivity has been compared with those reported in the earlier studies. It is observed that the sensitivity increases in the presence of metamaterial.

Optical Measurement of Forming Limit and Formability of Cu/Al Clad Metals

A digital image deformation measurement and analysis control system (XJTUDIC 8.0) was employed to measure the forming limit strain for Cu/Al clad metals produced via explosive welding technique. A contrast test between the digital image correlation (DIC) method and the conventional grid method was also implemented using the SPCC sheet metal forming limit test. The effect of heat treatment and contact status on forming limit was discussed based on the forming limit strain of Cu/Al clad metals. The interfacial and fracture structures were analyzed using scanning electron microscopy. The fracture site was predicted by finite element method. Results demonstrate that the forming limit curve of Cu/Al clad metals through DIC is more likely to reflect the formability of SPCC accurately. The forming limit of the clad with Al in the inner layer is higher than that of the clad with Cu in the inner layer. The formability of the annealed clads is superior to that of the non-annealed clads. The local interface failure induces the microcracks in Cu/Al clad metals during the forming process, which could be the main failure mode. With the finite element method, the fracture location of Cu/Al clad metals caused by uniaxial tensile during the forming limit test using DIC method is predicted accurately.

A parity-time symmetric coherent plasmonic absorber-amplifier

Non-Hermitian parity-time (PT)-symmetric optical potentials have led to a new class of unidirectional photonic components based on the spatially symmetric and balanced inclusion of loss and gain. While most proposed and implemented PT-symmetric optical devices have wavelength-scale dimensions, no physical constraints preclude development of subwavelength PT-symmetric components. We theoretically demonstrate a nanoscale PT-symmetric, all-optical plasmonic modulator capable of phase-controlled amplification and directional absorption. The modulator consists of two deeply subwavelength channels composed of either gain or loss dielectric material, embedded in a metallic cladding. When illuminating on-resonance by two counter-propagating plane waves, the aperture's total output can be modulated by changing the phase offset between the two waves. Modulation depths are greater than 10 dB, with output power varying from less than one half of the incident power to more than six times amplification. Off-resonance, the aperture possesses strong phase-controlled directionality with the output from one side varying from perfect absorption to strong scattering and transmission. The device design provides a platform for nanoscale all-optical modulators with gain while potentially enabling coherent perfect absorption and lasing in a single, compact structure.

Lateral shift assisted by guided modes on a metal cladding planar waveguide of micrometer scale

We investigate the lateral shifts of both the reflected and transmitted beams when a Gaussian beam is incident on a symmetrical metal cladding planar waveguide of micrometer scale. Different from the other schemes, the shifts are greatly enhanced when the guided modes are excited and cannot be attributed to the Fabry–Perot like resonance. Owing to the absorption of the metal films, the lateral shifts corresponding to the reflected and transmitted beams are not the same. The displacement of the transmitted beam can be negative, by suitable adjustment of the parameters of the structure, such as the incident angle, wavelength, and etc. Near the resonance dip of the reflection spectrum, the reflected beams undergone significant distortion and may split into two parts with positive and negative shifts, respectively.

Evaluation of microstructure and texture across the welded interface of super duplex stainless steel and high strength low alloy steel

The evolution of microstructure and texture across the fusion boundary of a dual-layer super duplex stainless steel clad metal produced on a high strength low alloy steel substrate by gas tungsten arc welding process was examined by optical microscopy, X-ray diffraction, electron backscatter diffraction, and energy-dispersive X-ray spectroscopy. It was found that a martensitic band with occasional Type I and Type II boundaries separated the substrate's heat affected zone from the high austenite containing region of the clad metal. Due to the competitive growth, both the ferrite and austenite grains showed almost the same <001>║ND orientation near the fusion boundary. While the texture of the austenite was not as strong as that of the ferrite across the cladding layers, the results confirmed that the austenite daughter phase was formed with a close Kurdjumov–Sachs orientation relationship with respect to the parent ferrite phase. It was also found that although both the residual stress and reheating caused some microstructural transformation and texture modification to some parts of the cladding, the major factors affecting the texture were unidirectional solidification, competitive growth, and δ/γ orientation relationship. The only exception was related to the occasional highly deformed mostly austenite area adjacent to the fusion boundary, where partial recrystallization led to formation of some annealing twins. The findings suggested that the reheating which occurred during the deposition of the second layer generated higher ferrite content and produced some secondary austenite with dominant Widmanstätten morphology across the first cladding layer. Moreover, it imposed higher residual strain and also promoted limited recrystallization adjacent to the fusion boundary.