Aluminum Clad Research Articles

Antimicrobial Performance of Different Metals

Health care associated infections or nosocomial infections (NI) is the fourth leading cause of disease and the most common complication affecting hospitalised patients in addition to a minimum of 175,000 deaths every year in industrialised countries. The Center for Disease Control and Prevention (CDC) states that influenza is transmitted from person to person primarily via large virus-laden droplets or through direct or indirect contact with respiratory secretions when touching surfaces contaminated with influenza virus and approximately 80% of the infections are transmitted via touch surfaces. In the year 2020 the Coronavirus (Covid 19) spread has affected the global community and also caused a great concern for the people and health care workers with a global infected population of more than five million. With the ongoing population rise in the cities growing drug resistant bacteria, increasing infection rate in hospitals and communities, ageing world population strongly indicates the need to minimise the spread of infections via touch surfaces. Metals (and products manufactured from them) such as copper and silver are known to exhibit antimicrobial properties. These metals, or composites containing them, can be used as additives and incorporated into other materials such as paints, plastics and powder coatings to imbue these materials with antimicrobial properties. In this paper we present the inherent antimicrobial properties of a copper containing alloy, two alloys of hospital grade steel (304 and 316), extruded aluminium (606013), anodized aluminium (606013) and zinc clad aluminium (3003-7072). Additionally, these materials were coated in epoxy resin powder coating with and without silver based antimicrobial additive. The ability of these metal alloys to reduce the population of inoculated microorganism numbers was assessed via the international standard (ISO) 22196:2011 Measurement of antimicrobial activity on plastics and other non-porous surfaces.

Interaction of Polymethyl Methacrylate with Boehmite-Filmed Aluminum Cladding Under Gamma Irradiation

This paper presents an overview of ongoing work to qualify the Advanced Test Reactor (ATR) driver fuel elements that have been affected by irradiation-degraded polymethyl methacrylate (PMMA) flux wands. Irradiation testing was performed on PMMA material in contact with aluminum clad material. The cladding was prefilmed with a boehmite oxide layer, an important feature of the ATR driver fuel. The effects on the boehmite layer due to gamma irradiation of the PMMA-aluminum clad system were investigated. PMMA embrittlement, followed by softening and degradation, occurred at high radiation levels. Adhesion between the cladding and irradiated PMMA was observed. Flow testing at prototypic ATR flow rates demonstrated the effective removal of the adhered material. Measurements of the boehmite layer thickness were performed, and Raman spectroscopy was utilized to detect the presence of boehmite in the irradiated PMMA material.

Mechanical and anti-icing performance of superhydrophobic aluminum conductor by anodized oxide technique

Abstract Anodized oxide technology is a traditional surface treatment method used in the material engineering field to enhance the friction, anti-icing, anti-corrosion, and insulation properties of Al-based samples. Considering the anti-icing and insulation performance, anodized oxide technology has great application prospects in overhead transmission lines. In this study, the preparation process of Aluminum (Al) flat plates and Aluminum Cable Steel-Reinforce (ACSR) was explored by using anodizing technology to obtain superhydrophobic properties. Moreover, as the significant performance in the application of transmission lines, the mechanical performance (tensile strength) of Al conductors was evaluated to study the impact of anodized oxidation technology. The results show that anodized oxide technology can improve the tensile strength of aluminum clad steel bars and aluminum-stranded wires in ACSRs. In addition, the hydrophobicity and anti-icing performance of anodized wires can demonstrate potential application prospects in the field of anti-icing.

Molybdate and vanadate ions as corrosion inhibitors for clad aluminium alloy 2024-T3

Molybdate and vanadate ions were used as corrosion inhibitors for the clad aluminium alloy 2024-T3 in chloride solution to investigate the differences in their inhibitory effect. Electrochemical measurements in 0.1 M NaCl investigated the influence of inhibitor concentration from 0.5 mM to 250 mM, solution pH from 5 to 9 and immersion time at open circuit potential of up to 12 h. Both compounds act predominantly as anodic inhibitors; however, the effect of molybdate increases significantly at concentrations above 50 mM and leads to a broad passive range. Surface analysis of the samples exposed to inhibitor performed by X-ray photoelectron spectroscopy showed that the inhibitor layers consist of oxides of multiple valences. Scanning electron microscopy with chemical analysis was also used to characterise the inhibitor layers. Equilibrium diagrams of the aqueous species in the selected concentration range were generated to better understand the inhibition mechanism and to correlate the electrochemical data and data on surface properties.

Synergistic solid–liquid composite and rapid solidification preparation of aluminum-clad steel wires

Solid-liquid composites and rapid solidification were synergistically employed to improve the interfacial-bonding and mechanical properties of prepared aluminum-clad steel wires. The effects of the process parameters on the performance of the wires were studied. The experimental results showed that good metallurgical interfaces can be prepared because of the synergistic strengthening effects between the solid–liquid composite and rapid solidification. The interfacial diffusion zone composed of FeAl3 and Fe2Al5 increased the bonding strength of the wires by 13 % compared with that of wires prepared by using the rolling process. The equiaxed fine crystal tissue morphology of the cladding aluminum and twin crystal organization resulted in good mechanical properties. Compared with LB35 and LB40, the conductivity and tensile strength were increased by 14 % and 22 %, respectively.

Experimental Determination of Springback Characteristics in a Three-Point Bending Test of the Aluminium Alloy Sheet with Aluminium Cladding

Experimental Determination of Springback Characteristics in a Three-Point Bending Test of the Aluminium Alloy Sheet with Aluminium Cladding

Influence of cladding attachment structural elements on the thermal performance of lightweight steel-framed walls

The thermal transmittance characteristics of the building envelope significantly influences the whole building energy performance. Lightweight steel framed (LSF) systems with cladding attached back to structures using thermal clips or bracket systems are widely used in heating dominated climates. Thermal bridging associated with the cladding structural elements that bypass the exterior insulation to attach the cladding cannot be avoided, but their impact can be significantly mitigated. This study investigates the thermal influence of a generic aluminum cladding attachment system that has varying levels of complexity associated with thermal breaks, and rail penetration into the insulation. A total of five configurations were assessed besides a reference configuration, which was devoid of any cladding attachment structure. Three-dimensional finite element software (HEAT3) and a small-scale calibrated hot box apparatus were employed to perform the analyses. The objectives were to show the influence of the cladding attachment elements and demonstrate the ability of hot-box measurements and numerical simulations to quantify the influence. Results show a small deviation between numerical simulations and experimental measurements, ranged between - 0.85% and 3.70%. The variations in thermal transmittances properties of the investigated wall assemblies are presented, which vary from 40% to 57% compared to the reference case. These findings highlight the significant influence of the structural elements that bypass exterior insulation and how small variations of the same system can impact the whole thermal performance. The heat loss through the cladding attachment structural elements, which bypass exterior insulation, can be reduced by using thermal breaks like neoprene spacers appropriately.

Research on identification method of transformer winding material based on vibration characteristic

At present, there are shoddy transformers in the market, of which the windings are replaced by aluminum and copper clad aluminum. The commissioning of these transformers may cause poor power supply performance and excessive winding heating. The existing detection methods of windings are complex, time-consuming to operate and destructive. Therefore, a winding material identification method based on vibration characteristics is proposed. Firstly, the vibration accelerations of transformer cores and windings with different winding materials are theoretically derived. Furthermore, through the coupling simulation of magnetic field and structure field of distribution transformers, the calculated vibration characteristics of copper, aluminum, and copper clad aluminum are verified. Finally, by comparing the time domain, the frequency domain and time-frequency domain of acceleration signals, preliminary identification of winding materials is conducted, which lays a theoretical foundation for establishing a precise identification model for winding materials in the future. This work provides guarantee for the safe operation of the distribution network.

Rain impact noise on aluminium cladding and the mitigation by damping materials

Raindrops on aluminium panels generate rain impact noise. Such percussive sound may reach 70 dBA in the nearby vicinity, causing disturbances to human activities and creating a nuisance. In Hong Kong, the use of curtain walls and aluminium wall cladding as the main building envelope has become a trend. The annual rainfall of 2.4 meters (94 inches) in Hong Kong amplifies this issue. Rain impact noise is increasingly affecting people and has become a growing concern. Effectively mitigating rain impact noise has become important in modern building design. This study focuses on the effect of different damping materials on rain impact noise when tested according to ISO-140-18:2006. It also includes an in-depth analysis of the correlation between vibration levels and sound levels generated under different testing configurations. The results showed that, with suitable treatment to the aluminium panel, the generated noise can be reduced by 15 dBA.

Thermomechanical Performance Assessment of U-Mo Monolithic Fuel Plates With Zircaloy Cladding

Abstract Performance of two distinct fuel systems, U-7Mo fuel in Zircaloy (Zry-4) cladding and U-10Mo fuel in aluminum (Al6061-O) cladding was studied. First, a mini plate with Zry-4 cladding from a previous irradiation experiment was evaluated via finite element analysis (FEA). By using the same plate geometry and irradiation conditions, another plate consisting of U-10Mo fuel and Al6061-O cladding was simulated. The results were then comparatively evaluated to explore the feasibility of employing Zry-4 as an alternative cladding. Simulations indicated the Zircaloy cladding plate would operate roughly 50 °C hotter as compared with the Al alloy cladding plate. Larger deformations in the thickness direction for the plate with Zry cladding were noted. It was observed that the postfabrication stresses in the fuel would be relieved quickly in the reactor, regardless of cladding type. Although the fuel stresses would still develop at reactor shutdown, the fuel would be stress-free during the entire irradiation period for both cladding types. At shutdown, the plate with Zry cladding would have higher stresses due to higher operating temperatures. Similarly, the stresses after shutdown are higher in the foil core for the plates with Zry cladding. The Al cladding plate would have higher plastic strains as compared with the Zry cladding plate. The Zry cladding plate is significantly stiffer, causing higher stresses in the fuel zone and at the interface. Overall, employing Zry as an alternate cladding is not expected to produce a more favorable thermomechanical performance as compared to the performance of an Al alloy cladding plate.

Micro X-ray computed tomography examination of mini plate fuel with hot isostatic pressed aluminum cladding

In order to minimize proliferation risks and improve security of nuclear material, the United States high performance research and test reactors (USHPRR) program is tasked with converting nuclear reactors that are fueled with highly enriched uranium (HEU) fuels to operate with low-enriched uranium (LEU) nuclear fuels. One favorable LEU fuel configuration is plate fuel with a metallic uranium-molybdenum foil clad within an aluminum alloy (AA 6061). In this fuel, the aluminum cladding is bonded with a hot isostatic pressing (HIP) method to seal the cladding around the fuel meat. However, the HIP process parameters influence the cladding performance, as a defective or incomplete bond can cause a pathway for corrosion. Micro X-ray computed tomography (XCT), a nondestructive technique that provides volumetric imaging, can be applied to inspect fuel plate cladding at the engineering scale. In this work, XCT methodology was developed and successfully utilized to not only observe the bond line of unirradiated mini fuel plates, but to also identify subsurface abnormalities in the plates’ cladding. In future work, this technique could be applied to fuel plates, pre- and post-irradiation, to quantify irradiation effects on cladding defects and bond line integrity.

Preparation and performance testing of clad aluminum pigments

The organic pigment permanent red F3RK was precipitated on the surface of aluminum pigment by precipitating agent BaCl2·2H2O, and then carbon black was added to produce the organic pigment with metallic luster and strong covering power, and the performance of the coated aluminum pigment was analyzed by testing. Experiments show that the organic pigment firstly forms a uniform and dense coating layer on the surface of aluminum pigment, and the amount of hydrogen precipitation is stable at 30 mL after 48 h compared with that of unwrapped aluminum pigment under the weak alkaline environment of 40 °C, pH = 9. Test analysis showed that F3RK was oxidized and condensed during the reaction process, and bonded to the surface of the aluminum pigment, introducing new amino groups, attached to the surface of the aluminum pigment, and possessing better alkali resistance.

The high‐frequency phenomenon of copper clad aluminum wires which are lower the alternating current resistance than copper solid wires, and the application of copper clad aluminum wires to the electrical equipment

AbstractThe paper is proposed approximate formulas of the ac resistance of lead wires and coils which made by using copper clad aluminum (CCA) wires. There are the frequency range that the ac resistance of CCA wires is lower than it of cupper solid wires for lead wires and coils of an electrical equipment. It is shown that the application of CCA wires is economical as comparing with copper solid wires, if the design is due to successful calculation in the electrical equipment. The measured resistance is compared with the formula. CCA wires is an example of multiple conductors which shall be expected to apply in future.

Indentation modelling of aluminium cladding panels subjected to hailstone impact

In spite of colossal damage caused to aluminium panels in hailstorms, there is currently no rational design procedure found on research to regulate the design of building claddings or rooftops to withstand hail impact. Damage predictive models that have been reported in the literature are not suited to predicting hail induced damage. Thus, insurance premiums on damage to aluminium cladding caused by hail cannot be set to fairly distribute risks. In the current study, an analytical model for predicting permanent indentation generated by the impact of a hailstone is presented. The model was developed from a combination of plate theories and results from thirty-seven full scale impact experiments conducted on 900 mm ×900 mm aluminium panels. The model presented in this article takes into account strain rate effects and has been demonstrated to give predictions that are within some 10% difference from experimental measurements.

Cladding and Butt-Joining Dissimilar Aluminum Alloys Simultaneously via Shear Assisted Processing and Extrusion

Cladding and Butt-Joining Dissimilar Aluminum Alloys Simultaneously via Shear Assisted Processing and Extrusion

Improvement in heat resistance of electric heating alumite carriers

Alumite carriers were prepared by using Al/Ni-Cr-Alloy/Al clad materials with different Pore widening treatment (PWT) durations of 0, 2, 4, 6 and 8 h to observe its effect on the alumina surface structures and the overall heat resistance. Aluminum clad materials were first anodized in 298 K 4 wt% oxalic acid with 50 A/m2 electric current. Subsequently, PWT was carried out in the same oxalic acid solution at 298 K. After calcination at 623 K for 1 h, samples underwent Hot water treatment (HWT) in 358 K hot water for 2 h before lastly calcinated at 773 K for 3 h. It was found that heat resistivity improved drastically when PWT was carried out for longer than 6 h. Results also showed that alumite carriers’ surface structure changed drastically after 6 h of PWT from fragment structure into a sponge-like structure. By manipulating the PWT durations, alumite carriers produced successfully withstood up to 1223 K without needing to induce diffusion layers by preheating. Therefore, alumite carriers produced with 6 h and 8 h of PWT showed promising potential for the usage in high temperature steam reforming reactions with electric heating.

On the Springback and Load in Three-Point Air Bending of the AW-2024 Aluminium Alloy Sheet with AW-1050A Aluminium Cladding.

This article presents the results of an analysis of the bending load characteristics and the springback phenomenon occurring during three-point bending of 1.0 and 2.0 mm thick AW-2024 aluminium alloy sheets with rolled AW-1050A cladding. A new proprietary equation was proposed for determining the bending angle as a function of deflection, which takes into account the influence of the tool radius and the sheet thickness. The experimentally determined springback and bending load characteristics were compared with the results of numerical modelling using different models: Model I, a 2D model for a plane deformation state, disregarding the material properties of the clad layers; Model II, a 2D model for a plane deformation state, taking into account the material properties of the cladding layers; Model III, a 3D shell model with the Huber-von Mises isotropic plasticity condition; Model IV, a 3D shell model with the Hill anisotropic plasticity condition; and Model V, a 3D shell model with the Barlat anisotropic plasticity condition. The effectiveness of these five tested FEM models in predicting the bending load and springback characteristics was demonstrated. Model II was the most effective in predicting bending load, while Model III was the most effective in predicting the amount of springback after bending.

The High-frequency Phenomenon of Copper Clad Aluminum Wires which are Lower the Alternating Current Resistance than Copper Solid Wires, and the Application of Copper Clad Aluminum Wires to the Electrical Equipment

The paper is proposed approximate formulas of the ac resistance of lead wires and coils which made by using copper clad aluminum (CCA) wires. There are the frequency range that the ac resistance of CCA wires is lower than it of cupper solid wires for lead wires and coils of an electrical equipment. It is shown that the application of CCA wires is economical as comparing with copper solid wires, if the design is due to successful calculation in the electrical equipment. The measured resistance is compared with the formula. CCA wires is an example of multiple conductors which shall be expected to apply in future.

Technical basis for extended dry storage of aluminum-clad spent nuclear fuel

This paper presents the technical basis for extended dry storage of aluminum-clad spent nuclear fuel (ASNF). This basis addresses and closes five knowledge gaps defined by the U.S. Department of Energy (DOE) Spent Nuclear Fuel Working Group (SNFWG) in DOE-ID/RPT-1575 “Aluminum-clad Spent Nuclear Fuel: Technical Considerations and Challenges for Extended (>50 Years) Dry Storage.” The SNFWG's primary concern pertaining to dry storage of ASNF is rooted in the presence of (oxy)hydroxide layers adherent to the aluminum cladding of the spent fuel that formed in service, indicating a risk of radiolytic molecular hydrogen (H2) generation in a strong gamma radiation field—a process that can be associated with disintegration of (oxy)hydroxide and the molecular decomposition of chemisorbed and physisorbed water bonded to it. Potential consequences are overpressurization of sealed ASNF dry storage canisters and creation of a flammable atmosphere in sealed and vented canisters. Further, there is the concern that the generation of other chemical species due to chemical reactions, such as nitric acid (HNO3), could lead to canister component corrosion. To address these issues, experimental work was conducted, including investigations of the performance of surrogate aluminum specimens and actual ASNF material featuring adherent (oxy)hydroxide layers during wet or dry storage. Further, a comprehensive characterization of the sample material was completed. Drying experiments were executed, providing better estimations of the amount of residual, chemisorbed, and physisorbed water after ASNF dry storage canister conditioning. These empirical activities allowed for the development of predictive numerical models to simulate the chemical species yield within sealed and vented dry storage canisters for 50 years. The findings of these activities lead to the main conclusion that extending current ASNF dry storage durations by 50 years is both safe and viable.

Effect of Ni and Fe elements on microstructure and high temperature oxidation behavior of laser cladding aluminum bronze coating

In this work, two kinds of aluminum-bronze coatings were successfully prepared on 316 stainless steel substrate by laser cladding technology. The changes of microstructure and high temperature oxidation behavior of pure aluminum bronze laser cladding layer before and after adding Ni and Fe elements were studied and compared. The results show that a certain amount of κ phase and Fe–Cr phase are constituted in the modified coating with the addition of Ni and Fe elements, which refines the structure and grains. The main components of the oxide layer of the two coatings are Al2O3. In the high temperature oxidation process, both two coatings experienced the formation, spallation, and recovery of an oxide film. The time to form a stable oxide film on the surface of the modified coating is significantly shorter than that of the original coating. As a result of the formation of fine and dense oxide particles on the modified coating's surface, the stability and internal stress resistance of the oxide film is superior. Under the condition of 1000 °C oxidation for 100 h, the oxidation film thickness and oxidation rate constant (kp) of the modified coating are about 0.88 and 0.79 times of that of the original coating. The addition of Ni and Fe can greatly enhance the laser cladding aluminum bronze coating's resistance to high-temperature oxidation.