Al Plate Research Articles

Performing a comparative study of mechanical properties of Al-Cu composite reinforced with or without bimetallic SiC micro-particle

Butt weld between Al6063-Cu is produced with or without reinforcing SiC (25 µm) to analyze its effect on IMC formation. Al plate is kept on advancing side throughout the process. As a result its observed that on with reinforcement workpiece is less prone to defects when compared with the one without reinforcement and parameters like tool tilt, tool speed, tool offset serves as the critical parameter as a slight change in one leads to significant change in quality of joint produced. It is observed that the best joint is produced with reinforcement taking tool tilt as 1° at 1500 rpm and tool offset of 0.5 mm towards Cu side results in tensile strength of 81.7 MPa and without reinforcement the best joint is obtained at a tool tilt of 2°, tool speed as 900 rpm at 0.3 mm tool offset provided on Cu side resulting in tensile strength of 79.3 MPa keeping a constant feed rate of 7 mm/min.

Eliminating intermetallic compounds via Ni interlayer during friction stir welding of dissimilar Mg/Al alloys

There is a substantial demand in transportation industries to join dissimilar Al and Mg alloy to reduce the structural weight further. However, it is challenging to produce high-strength joints of Al/Mg even with friction stir welding due to the formation of intermetallic compounds (IMCs). In a quest to suppress/eliminate the IMCs, we propose to add a Ni interlayer in a sandwich form between the Mg and Al plates. Widely used and industrially applicable AA6061-T6 and AZ31B Mg alloys are taken for experimentation in the present study. The Ni interlayer's effects on microstructure, mechanical properties, and IMCs characterization are studied. The Ni interlayer can drastically cease the molecular diffusion of Mg and Al across their interfaces, and typical IMCs Al3Mg2 and Al12Mg17 are eliminated. Significant dispersion of Ni with Al and Mg is found in the weld zone, which forms Al3Ni and Mg2Ni compounds. The energy-dispersive X-ray spectroscopy confirms the efficacy of Ni addition to wipe out the β and γ IMCs phases. The localized fracture analysis of Ni interlayered joint suggests dual-mode failure, i.e., ductile and brittle. The mechanical testing advocates better weld quality for Ni interlayered joints compared to its conventional ones.

Growth characteristics and corrosion resistance of micro-arc oxidation coating on Al–Mg composite plate

To investigate the growth characteristics and corrosion resistance of Micro-arc oxidation (MAO) coatings prepared from Al–Mg composite plates under sodium silicate electrolyte, comparative experiments were performed using single plate Al and Mg. The results showed that the breakdown of the Mg plate (P–Mg) in the Al–Mg composite plate occurred first than the Al plate (P–Al). The coating thickness of P–Al and P–Mg gradually converged with time. Because after the Al and Mg plates composite, the increased energy consumption of the P–Al made its discharge more intense and accelerated the growth of its coating, while the situation of the P–Mg was opposite. The SEM observation discovered that the coating defects in P–Al and P–Mg coatings showed a gradually increasing trend as time passed. The corrosion resistance tests showed that MAO could effectively improve the corrosion resistance of the Al–Mg composite plate. Compared with the substrate, the corrosion rate of the P–Al coatings was reduced by more than one order of magnitude, while that of the P–Mg coatings was reduced even more. After soaking in 3.5 wt% NaCl solution for 36 h, the corrosion mass loss of Al–Mg composite plate treated by MAO was reduced by at least two orders of magnitude.

Bremsstrahlung Generation by 7.5 Mev Electrons in Converters Made of Different Materials

The present paper shows that, besides the technologically complex water-cooled converters made of Ta or W, a simple and efficient converter in the form of air-cooled Mo and Al plates can be fabricated for a number of tasks. The generation of bremsstrahlung by electrons with the energy of 7.5 MeV in the converter plates made of Ta, W, Cu or Mo and in the Al filter was studied by the Monte Carlo method in the PENELOPE software package. The thicknesses range of the plates made of Ta, W, Cu or Mo was chosen on condition that the total mass thickness of the converter and filter made of Al (in g/mm2) provided complete absorption of the primary electrons. It is shown that the photon yields from Mo at mass thicknesses above 25 g/mm2 are higher than those from Ta and W, but the energy transferred from electrons to BS is lower. With the same mass thicknesses of Ta and W converters, practically all characteristics of bremsstrahlung and the absorbed energy in the target are the same. The conditions for cooling the converter elements with water and air are determined for the level of heat release in the converter up to 10 kW. The minimum dimensions of the electron-irradiated region of Ta and Mo converters, cooled by water, are determined. It is shown that with the really existing air compressors taken into account, the permissible heat release of air-cooled Mo converters should not exceed 4 kW.

Development and application of novel high throughput metal waste chips and foam electrodes for electrocoagulation treatment of graywater

ABSTRACT In this study, novel high throughput metal waste chips and foam electrodes were developed for the electrocoagulation of graywater for the first time. The developed electrodes were then compared with traditional metal plate electrodes, which showed higher efficiency of developed electrodes. The effective parameters of pH, electrode distance, applied voltage, and reaction time on COD removal were optimized using RSM as a multivariate optimization technique, and the data were analyzed by ANOVA, normal plot, residual distribution, and 3D plots. The optimal conditions for electrocoagulation of graywater using metal (Al) plate electrode were determined as a pH of 6.86, electrode distance of 5 mm, and applied voltage of 5 V for a reaction time of 10 min, resulting in 89.1% COD removal and 74% turbidity removal. Finally, the performance of aluminum plate electrodes, foam electrodes, and electrodes made from metal waste chips was compared using COD removal efficiency as the index, revealing 84%, 93%, and 87% COD removal, respectively. These results demonstrated that the newly developed electrodes are suitable for graywater treatment with excellent COD removal efficiency, metal chip waste recycling, and cost-saving.

Self-Ordering of Porous Anodic Alumina Fabricated by Anodizing in Chromic Acid at High Temperature

Anodizing Al in chromic acid is a very useful surface finishing process for corrosion protection and nanoscale porous structure fabrication, whereas the self-ordering of porous anodic alumina (PAA) in chromic acid has never been found to date. Herein, we provide a self-ordered PAA film possessing numerous sub100-nm-scale characteristic bumps through anodizing in chromic acid at high temperature. Anodizing of high purity Al plates in a 0.3 M chromic acid solution at conventional low temperatures, such as 293 K, leads to the formation of a disordered PAA film, whereas anodizing at a high temperature of 348 K causes the self-ordering behavior of the pore structure. The PAA film grown in the initial stage possessed the highest regularity, and it decreased with anodizing time due to pore branching during anodizing. A highly ordered PAA film measuring approximately 340 nm in interpore distance can be fabricated by short-term, two-step anodizing in chromic acid at 348 K and 120 V. The ordered PAA film possesses a characteristic nanostructure consisting of hexagonally arranged 100-nm-scale pores and sub100-nm-scale disordered bumps on their pore walls without any electrolyte chromate anion.

Effect of damping material thickness on vibration analysis in pretension layer damping process

Vibration reduction is a critical necessity in many fields of engineering, technology, and industry. As a result, there is a need for vibration management. To restrict or adjust the system’s vibration response, a variety of techniques are employed. In recent years, there has been a lot of enthusiasm for the easy implementation of these vibration-control structures. The damping properties of viscoelastic materials tend to be excellent. Damping is determined by the material’s ability to dissipate energy. To minimise the vibration of vibrating surfaces, viscoelastic materials are commonly used. In this study, viscoelastic material (Dyad 606) is applied on the AL plate in the form of free layer damping and pretension layer damping. First aluminium structure using free layer damping and another one using pretension layer damping by applying tension load (two layers of damping plates, one on the top surface of the Al alloy and the other on the lower face). Passive vibration damping of the plate is achieved. These layers are influenced by axial uniform distributed load. The damping behaviour of the AL Plate is discussed in relation to the thickness variation of the pre-tension damping material. The results show that the loss factor and the attenuation percentage of the structure with pretension layer damping are increased as compared to free layer damping. It is also found that the most effective thickness of the damping material to increase the damping capacity of the framework is around half the base plate thickness

Evaluation of superior layer configuration of titanium Ti-6Al-4V and aluminium 2024-T3 against soft projectiles

The manuscript is focussed on the prediction of superior layer configuration on titanium and aluminium plates through numerical investigations using ABAQUS/Explicit finite element software. The target plate of titanium Ti-6Al-4V (Ti) and aluminium Al 2024-T3 (Al) were studied against 7.62 mm diameter soft lead core projectiles. The Johnson-Cook (JC) material model was employed to simulate the behaviour of the target as well as projectile material. The results thus predicted from the numerical simulations in terms of deformed profile, residual velocity and ballistic limit were compared with the experimental results available in literature. Overall, the results were found in good agreement with the experimental results. The simulations were performed on the target of 10, 12.7 and 15 mm thickness with three, five and ten layers in order to predict the superior layer configuration. In the case of Ti-6Al-4V, the difference in performance between three layers and monolithic was quite high, however the use of five or ten layers of equivalent thickness is not advisable as performance is reduced. For Al2024-T3, the performance of layer targets was quite similar to that of monolithic targets. It is also observed the resistance of TiTiAl target configuration found to be better as compared to AlTiTi target configuration. It is concluded that the Al plate as back layer has more efficiency for ballistic resistance of layered configuration. It is also concluded that with respect to thickness, the capacity of titanium target is approximately 1.5 times higher than aluminium target against given lead core projectile.

Preparation of Ti/Al composite plates by differential temperature rolling with induction heating

In the current study, we proposed a method of differential temperature rolling with electromagnetic induction heating to prepare Ti/Al composite plates in a protective atmosphere to realize the homogeneous deformation of Ti/Al bonding rolling and improve the interfacial bonding strength of the composite plates. The temperature field required for homogeneous deformation rolling of titanium and aluminum was constructed using finite element simulation by adjusting the parameters of electromagnetic induction heating, which made a temperature difference of about 632 °C between titanium and aluminum, and the temperature of each plate was relatively uniform. The induction heating experiment was designed based on the finite element simulation, and the experiment verified the accuracy of the simulation results. The effects of rolling temperature and reduction rate of homogeneous deformation and bonding strength of Ti/Al composite plates were evaluated by rolling experiments. With the increase of rolling temperature and reduction rate of titanium, when the heating temperature of the Ti plate is 750–850 °C, and the reduction rate is 30%–48%, the reduction rate of Ti plate and Al plate gradually tend to be the same. When the titanium plate and aluminum plate temperature is 850 °C and 188 °C, respectively, with a rolling reduction rate of 48%, the deformation rate of Ti plate and Al plate is 46.8% and 48.6%, respectively. Moreover, the bonding strength of the composite plate reaches 77MPa.

Influence of pore morphologies on the mechanical and tribo-electrical performance of polydimethylsiloxane sponge fabricated via commercial seasoning templates

This work demonstrated the influence of pore morphologies on the mechanical behavior and tribo-electrical performance of fabricated polydimethylsiloxane (PDMS) sponge. Commercial seasonings with different 3D geometric shapes were used as a sacrificial template to control the pore structure of the PDMS sponge. The result indicated that the softest PDMS sponge was molded by using a sodium chloride (NaCl) crystal template, as indicated by the lowest compressive modulus value. Then, P(VDF–HFP) was incorporated into PDMS prepolymer in order to enhance the charge generation characteristic of PDMS. Besides, the composite 3D structure was revealed using synchrotron radiation X-ray tomographic microscopy (SRXTM). Interpretation from the SRXTM result confirmed that the porous structure had different pore shapes, i.e., an octahedral-like shape and a circular-like shape in a particular sponge. By pairing the composite PDMS sponge with an aluminum (Al) plate for the triboelectric nanogenerator (TENG), the maximum electrical outputs of ~29.9 V and ~0.56 μA for voltage and current, respectively, were detected with loading 50 wt% of P(VDF – HFP). The presented TENG was applied successfully for sensing basic human activities practically, which demonstrated potential applications in wearable electronics.

Economically reproducible surface-enhanced Raman spectroscopy of different compounds in thin film

We report herein an economically cheap and functionally stable surfaceenhanced Raman scattering (SERS) protocol of two photoactive pigments Rhodamine 6G (R6G) and Kiton Red (KR), implemented in thin films of silver (Ag) and gold (Au) nanoparticles (AgNPs and AuNPs). Both commercially available and chemically synthesized nanoparticles were used. The suitability of the nanoparticles toward SERS activity was tested through UV-visible absorption spectroscopy and scanning electron microscopy (SEM). The AgNPs and AuNPs based SERS substrates in the form of films were fabricated onto square-sized aluminum(Al) plates by simple drop deposition of colloidal nanoparticles solution onto their polished surfaces. The prepared nanoparticle films were sufficiently dried and coated further with the probe (R6G and KR) molecules by employing the identical deposition technique. The enhanced Raman signals of R6G and KR in such composite film structures were then recorded through a custom-built dispersive Raman spectrometer with He-Ne laser excitation at 632.8 nm. Our AgNPsfilm-based SERS protocol could yield the magnitude of the Raman signal enhancement up to 104 times for both R6G and KR. Moreover, AuNPs-based film was found to be less efficient toward the Raman enhancement of both compounds. Our SERS substrates can be easily fabricated, and SERS spectra are reproducible and stable, allowing one to consistently get a reproducible result even after 6 months.
 J. Bangladesh Acad. Sci. 45(1); 1-11: June 2021

Nanoscale Coatings Derived from Fluoroalkyl and PDMS Alkoxysilanes on Rough Aluminum Surfaces for Improved Durability and Anti-Icing Properties

Anti-icing aluminum (Al) surfaces with excellent durability and low icing adhesion strength were fabricated by forming hierarchical structures on Al surfaces and coating silanes with low surface energy. The Al plates were chemically etched and subsequently immersed in hot water to realize micro–nano hierarchical roughness on the surface. The rough Al plates were coated with a solution containing a mixture of 1H,1H,2H,2H-heptadecafluorodecyl (FD)-trimethoxysilane and poly(dimethylsiloxane) (PDMS)-triethoxysilane, and the wettability and anti-icing properties of the coated surface were compared according to the various ratios of FD and PDMS. The anti-icing surface with 2.9 wt % of the PDMS functional group exhibited a relatively low ice adhesion strength of 25.3 kPa despite a high relative humidity of 75% (at −20.5 °C). In addition, the ice adhesion strength achieved after 100 icing/melting cycles was 47.2 kPa, which indicated excellent durability of the anti-icing properties. This is attributed to the synergistic effect of PDMS and the low surface energy of FD groups, which exhibit chain flexibility, low glass-transition temperature, and repulsion against water molecules.

Robust and flexible silver-embedded elastomeric polymer/carbon black foams with outstanding electromagnetic interference shielding performance

Designing robust, flexible, and low metal consuming hybrid foams for high-performance electromagnetic interference (EMI) shielding is crucial yet challenging. A new metallization strategy of foam type materials is presented to fabricate the robust and flexible silver embedded poly (styrene-block-butadiene-block-styrene)/carbon black hybrid foam (Ag@SBS/CB) with ultra-low silver consumption. The synergistic effect between the embedded isolate Ag nanoparticles and carbon black endows the Ag@SBS/CB foam with high mechanical and electrical stability as well as outstanding EMI shielding performance. The Ag@SBS/CB foam can endure over 1500 cycles of the compression-release test without detectable decay in the relative conductivity. A significant influence of the pore size and the silver fraction on the EMI shielding performance is revealed, providing an intriguing microstructure design strategy. The EMI shielding effectiveness (SE) of the foam reaches 81.3 dB with the silver fraction of 0.63 vol% and a CB fraction of 15 wt% at a thickness of about 5 mm. In particular, the Ag@SBS/CB foam with a thinner thickness of 2 mm shows a much better near-field EMI shielding than Al plate.

Production cross section measurements of proton-induced reactions on Nb at energies of 58 to 100 MeV

Production cross sections for the $^{93}\mathrm{Nb}(p,x)^{90}\mathrm{Mo},\phantom{\rule{0.28em}{0ex}}^{92m,90,89m}\mathrm{Nb},\phantom{\rule{0.28em}{0ex}}^{89,88,86}\mathrm{Zr}$, and $^{88,87m,87g}\mathrm{Y}$ reactions were measured using a stacked-foil technique in the proton energy range of 58--100 MeV. The target was arranged in the stack including Nb, Al, Au foils, and Pb plates and was irradiated with 100-MeV protons. After the irradiation, the production yields of the interested radionuclei were measured by a $\ensuremath{\gamma}$-ray spectroscopy system using HPGe detectors. Proton beam intensities were measured using the $^{27}\mathrm{Al}(p,3pn)^{24}\mathrm{Na},\phantom{\rule{0.28em}{0ex}}^{197}\mathrm{Au}(p,p3n)^{194}\mathrm{Au}$, and $^{197}\mathrm{Au}(p,pn)^{196}\mathrm{Au}$ monitor reactions. Some 54 cross section data points were measured, including independent and cumulative cross sections and were compared with other experimental data. The excitation functions of the reactions were also calculated by nuclear models using the talys code with a default mode as well as different nuclear level-density models. The calculated cross sections were compared to the measured data and to the tendl library. It was figured out that the theoretical calculations could reproduce the shape of the measured cross sections well, whereas the magnitude of the cross sections was not reproduced. It was also shown that the preequilibrium mechanism played an important role in the cross section calculations in this paper.

Effect of physical barrier and anion-exchange process of nitrate-intercalated ZnAl layered double hydroxide films grown on Al on corrosion protection

ZnAl layered double hydroxide (ZnAl-LDH) film loaded with nitrates was prepared on the surface of pure Al plate by hydrothermal reaction. The anion-exchange process of ZnAl-LDH in corrosive NaCl solution was demonstrated by the X-ray Diffraction (XRD). The corrosion protection behavior of this fabricated film was monitored by performing electrochemical impedance spectroscopy (EIS) up to 39 d. It was revealed that the physical barrier effect of nitrate-intercalated ZnAl-LDH film played a significant role in its corrosion protection and the anion-exchange had a limited influence on final corrosion protection.

Statistical guided-waves-based structural health monitoring via stochastic non-parametric time series models

Damage detection in active-sensing, guided-waves-based structural health monitoring (SHM) has evolved through multiple eras of development during the past decades. Nevertheless, there still exist a number of challenges facing the current state-of-the-art approaches, both in the industry as well as in research and development, including low damage sensitivity, lack of robustness to uncertainties, need for user-defined thresholds, and non-uniform response across a sensor network. In this work, a novel statistical framework is proposed for active-sensing SHM based on the use of ultrasonic guided waves. This framework is based on stochastic non-parametric time series models and their corresponding statistical properties in order to readily provide healthy confidence bounds and enable accurate and robust damage detection via the use of appropriate statistical decision-making tests. Three such methods and corresponding statistical quantities (test statistics) along with decision-making schemes are formulated and experimentally assessed via the use of three coupons with different levels of complexity: an Al plate with a growing notch, a carbon fiber-reinforced plastic (CFRP) plate with added weights to simulate local damage, and the CFRP panel used in the Open Guided Waves project, all fitted with piezoelectric transducers under a pitch-catch configuration. The performance of the proposed methods is compared to that of state-of-the-art time-domain damage indices (DIs). The results demonstrate the increased detection sensitivity and robustness of the proposed methods, with better tracking capability of damage evolution compared to conventional approaches, even for damage-non-intersecting actuator–sensor paths. In particular, the Z statistic emerges as the best damage detection metric compared to conventional DIs, as well as the other proposed statistics. Overall, the proposed statistics in this study promise greater damage sensitivity across different components, with enhanced robustness to uncertainties, as well as user-friendly application.

Oil-Infused Slippery Surface on Al Substrates Fabricated by Chemical Etching

In recent years, the oil-infused slippery surfaces inspired by Nepenthes pitcher have potential applications in domestic and industrial fields due to their excellent water repellence. However, the current preparation methods of the oil-infused slippery surfaces have the disadvantages of time-consuming, expensive equipment and complex processes. In our research, we reported an approach to prepare the oil-infused slippery surface with multi-functional applications by simple chemical etching. First, Al plates were etched by hydrochloric acid solution and modification with lower surface energy. Then, the as-prepared samples were immersed into the lubricant oil. After that, the oil-infused slippery surface with a water slide-off angle of 3° was obtained. The freezing rain tests, chemical stability tests, and self-cleaning tests were conducted on original Al plate and the as-prepared sample. This work will enrich the preparation methods of the oil-infused slippery surfaces.

Enhancement of UHMWPE encapsulation on the ballistic performance of bi-layer mosaic armors

The ballistic performance of a bi-layer armor encapsulated with ultra-high molecular weight polyethylene (UHMWPE) composite laminate was investigated using a combined experimental and numerical approach. Three series of test specimens were examined: (A) bare and encapsulated aluminum (Al) plates, (B) bare and encapsulated bi-layer mosaic armors, and (C) bi-layer mosaic armors having identical areal density but different encapsulation thicknesses. The ballistic behaviors and failure mechanisms of UHMWPE encapsulated Al plates and bi-layer mosaic armors under different projectile impact velocities were analyzed systematically. Attributed to the integration effect of encapsulation, the encapsulated specimens could effectively disperse localized projectile impacting to the entire structure. The results indicated that the UHMWPE encapsulation could enhance significantly the ballistic resistance of traditional ceramic/metal bi-layer armors, due mainly to serious pulling and stretching deformations of the lateral and rear UHMWPE laminates in resisting the projectile impact. However, thicker encapsulation would not necessarily lead to better ballistic performance for specimens with equal areal density. Further, the thickness (or mass) ratio of the armor substructures needed to be tailored synthetically to achieve optimal ballistic performance.

Analysis of Variance of Dissimilar Cu-Al Alloy Friction Stir Welded Joints with Different Offset Conditions

In this investigation, dissimilar material AA6061-T6 and Cu B370 were joined by friction stir welding (FSW). This paper presents a feasibility study of FSW to join Al-alloy and Cu-alloy. The experiment was conducted using general full factorial design by varying the tool rotation speed, weld speed, and probe offset, and by keeping the plunge depth constant. In this research work, a statistical model was established to build a connection between the process variables and outcomes—yield strength (YS), ultimate tensile strength (UTS) and % elongation (% E). Statistical tools such as analysis of variance and scatter diagrams were employed to evaluate the suitability of the models. In addition, the impacts of the process variables on the tensile properties were investigated. From the experimental results, it can be concluded that (i) an excellent weld joint could be obtained by keeping the softer Al plate at the retreating side with a probe offset of 2.0 mm towards the softer material, and (ii) maximum tensile properties were obtained at a higher tool-rotation speed, weld speed, and with a probe offset of 2.0 mm. Further, the fractured tensile specimens were investigated using a scanning electron microscope (SEM). From the analyses, it was noted that, during the tensile test, the weld joint failed with a brittle–ductile mixed fracture mode.

Influence of anodization parameters on film thickness and volume expansion of thick- and large-sized anodic aluminum oxide film

Anodic aluminum oxide (AAO) film with a thickness ranging from 20 to 100 μm was prepared using a large-sized Al plate (4 cm × 10 cm) to investigate the anodization parameter effect on the film thickness and volume expansion factor. A corrosion treatment (voltage = 0 V) was performed to investigate the film dissolution caused by acid. The actual anode surface temperature was also measured to confirm the field-assisted nature of AAO dissolution. The film thickness increases exponentially with temperature, and increases approximately linearly with voltage, duration or concentration. The volume expansion factor gives a first rising and then falling trend with temperature or duration, while it has a nearly linear trend with voltage or concentration. The volume expansion factor increases with the intensified electric field, while its decrease is attributed to the Joule heat-enhanced dissolution. In the case of large film thickness (> 20 μm), the pore confinement effect may be one of the reasons for the change of volume expansion factor. In addition to the conventional parameters, the heat transfer-related parameters (for example, sample size) also greatly affect the AAO film growth.