Aluminum Alloy AA Research Articles

Comparative electrochemical and thermodynamic study of cold-rolled steel, Al alloy AA5754, and Zn corrosion in fluoride and chloride solutions

This study investigates the effects of fluoride and chloride ions on the corrosion of cold-rolled steel, aluminium alloy AA5754, and zinc, using ammonium bicarbonate as a buffer at pH 4 and compares electrochemical findings with thermodynamic calculations of E-pH diagrams. The distinct electrochemical behaviours of fluoride and chloride ions were confirmed, with fluoride-induced corrosion leading to the significant complex formation on cold-rolled steel and AA5754, the latter leading to a narrowing of the Al passive region. However, a comprehensive analysis of all ionic species in the solution (F−, Cl−, NH4+ and HCO3−) and their complex equilibria reveals that zinc's corrosion is primarily influenced by the overall ionic strength of the solution and further complexation with the buffering agent at higher pH levels, should these conditions occur during corrosion. In addition, this analysis also highlights the subtle differences in the stabilization effects of open circuit potential on cold-rolled steel and AA5754. The results underscore the importance of considering the overall solution equilibrium in thermodynamic analyses and provide a foundation for further research on the role of F- and Cl- ions in zirconium conversion coatings.

Mechanical properties of layered composites based on AA1050 and AA5056 aluminum alloys produced by WAAM technology

Abstract The possibility of producing layered aluminum materials using wire-arc additive manufacturing (WAAM) technology has been investigated. Deformation characteristics of composites based on AA1050 and AA5056 aluminum alloys are considered. Mechanical tests of specimens with different orientations of AA1050 layers in AA5056 alloy matrix are presented. The results are analysed in the light of the structural characteristics of the composites.

Studies on air jet erosion behavior of plasma-sprayed Cr2C3 coatings on Al6061 alloy

This study assesses the efficacy of plasma-sprayed Cr2C3 coatings on AA6061 aluminum alloy in reducing erosion at different angles (30, 60, and 90°). The experimental setup involved maintaining a distance of 80 mm between the components, feeding the powder at a rate of 55 g/min, and applying a current density of 460 amps. Weight loss measurements and surface morphology analyses were performed using scanning electron and confocal microscopy. The findings suggest that the Cr2C3 coating significantly improves erosion resistance when compared to specimens without any coating. The erosion angle had a significant impact on the performance of the coating. The coating experienced the least weight loss at an angle of 30° (28.45 g), followed by increased losses at angles of 60° (30.34 g) and 90° (34.2 g). These findings emphasize the significance of the impact angle in determining the severity of material removal.

Correlated 4D-STEM and EDS for the classification of fine Beta-precipitates in aluminum alloy AA 6063-T6

Tuning the properties of aluminum alloys AA 6063-T6 involves artificial aging to induce precipitate formation, particularly β’’ and β’ phases. Previous characterization challenges due to their similar appearance are addressed here by correlating 4D scanning transmission electron microscopy (4DSTEM) and energy-dispersive spectroscopy (EDS) mapping. This approach allows us to analyze the structure and composition of precipitates individually, overcoming limitations of conventional imaging and structural analysis techniques when the precipitates appear simultaneously, as is often the case. We present detailed characterizations of needle-shaped Beta precipitates, revealing distinct diffraction patterns (DPs) and compositional differences. The method's applicability extends beyond aluminum alloys, offering a promising strategy for complex composite material characterization with multimodal scanning transmission electron microscopy (STEM) techniques.

Numerical Study on the Effect of Geometrical Changes on the Deformation Behaviour of Recycled Aluminium Alloy AA6061 undergoing High Velocity Impact using Hyperworks-Radioss

Numerical analysis is important to predict material behaviour without require an experimental implementation. This manuscript focuses on a numerical prediction establishment of a direct recycled aluminium alloys AA6061 undergoing Taylor Cylinder Impact test using Johnson-Cook model in HyperWorks Radioss. The numerical setup was first validated against the experimental data at the velocity range of 179 to 212 m/s. Good agreement between simulation and experimental data was obtained within the range that exhibits a mushrooming shape fracture mode. A parametric study was then conducted to study the deformation behaviour of the selected recycled aluminum alloys within the validated range at various geometrical settings. The analysis was made by focusing on the post-impact configuration of the projectile at different impact velocities in terms of residual length, deformed diameter, and the final length-to-diameter ratio. It was found that a broader projectile experienced a less significant reduction in its final length (Lf/Lo goes from 0.87 to 0.9 for projectile diameter 9mm to 34mm) and a smaller increase in the deformed diameter compared to a thinner projectile (Df/Do goes from 1.18 to 1.12 for projectile diameter 9mm to 34mm). It was found that a thinner projectile experienced more diameter expansion than length reduction post impact. In addition, a longer projectile experienced more residual length reduction (Lf/Lo goes from 0.92 to 0.87 for projectile length 2mm to 14mm) and more radial deformation compared to the one with a smaller initial length (Df/Do goes from 1.06 to 1.18 for projectile length 2mm to 14mm). All projectiles showed more significant changes on the deformed diameter compared to the changes in residual length post-impact. The results helped the understanding of a critical aspect of the deformation behaviour of recycled aluminum alloy AA6061 more effectively compared to experimental work implementation.

Electron Backscatter Diffraction Analysis of Microstructure in Spray Formed AA7050 Aluminium Alloy

Electron Backscatter Diffraction Analysis of Microstructure in Spray Formed AA7050 Aluminium Alloy

Characteristics analysis and monitoring of friction stir welded dissimilar AA5083/AA6061-T6 using acoustic emission technique

The joining of aluminum alloys using fusion welding often leads to issues such as hot tears, porosity, distortion, and solidifying cracks. To address these challenges, solid-state welding processes like Friction Stir Welding (FSW) are preferable. This study investigates the FSW of dissimilar aluminum alloys AA 5083 and AA 6061-T6, employing Acoustic Emission (AE) techniques for real-time monitoring. FSW was conducted under conditions with no defects, pinhole defects, and piping defects. The resulting joints were evaluated for their mechanical properties and metallurgical characteristics. Microstructural analysis was performed using an optical microscope, revealing that the defect-free condition achieved the highest tensile strength of 256 MPa and superior hardness of 93 HV at the stir zone. Tensile failure commonly manifested within the heat-affected zone (HAZ) of AA 6061-T6, primarily due to grain enlargement and the impact of Mg2Si precipitates. Examination of the fractured regions via scanning electron microscopy revealed ductile-mode fractures featuring elongated dimples and microvoids. AE parameters such as hits, amplitude RMS, and energy were analyzed, demonstrating that defect-free welds had consistent AE signal patterns, while significant variations were observed in pinhole and piping defect conditions due to larger defect areas. The findings suggest that AE monitoring is effective in detecting and analyzing welding defects, providing valuable insights into the FSW process for dissimilar aluminum alloys.

Surface Property Enhancement of Al–Si–Cu Alloy Coating by Fast Multiple Rotation Rolling

Herein, the effect of high rotational speed fast multiple rotations rolling (FMRR) on the microstructure, mechanical properties, and wear resistance of an Al–Si–Cu alloy coating friction surfaced on AA1050 aluminum alloy is investigated. The FMRR process is performed at a rotational speed of 3000 rpm with traverse speeds of 50, 80, 110, and 140 mm min−1. The microstructure, mechanical properties, and wear resistance are examined by optical microscope, scanning electron microscope, electron backscatter diffraction, transmission electron microscope, nanoindentation test, microhardness test, and pin‐on‐disc wear test. The results show that as the traverse speed increases from 50 to 140 mm min−1, surface roughness decreases from 6.3 ± 0.3 to 3.2 ± 0.2 μm. Additionally, with the increase in traverse speed, the coating height increases from 3.8 ± 0.3 to 4.7 ± 0.4 mm, while the coating width decreases from 37.1 ± 1.1 to 25.4 ± 1.3 mm. Furthermore, as the traverse speed increases from 50 to 140 mm min−1, the average hardness of the FMRR‐processed layer increases from 5.6 ± 0.6 to 10.2 ± 0.6 GPa. At a traverse speed of 140 mm min−1, the wear resistance of the FMRR‐processed layer increases by 20% compared to the Al–Si–Cu alloy consumable rod.

Effect Analysis of Process Parameters on Geometric Dimensions during Belt-Heated Incremental Sheet Forming of AA2024 Aluminum Alloy

The effect of process parameters on geometric dimensions is complex during belt-heated incremental sheet forming, leading to control difficulties in the geometric dimension of parts. In this study, the geometric errors were analyzed under the action of different process parameters, and the corresponding influence law was obtained through macro- and microexperiments. On this basis, the micromorphology of the deformation region section was analyzed in detail, and the effect of process parameters on micromorphology characteristics was obtained during belt-heated incremental sheet forming. Meanwhile, the dislocation density of the deformation region section was analyzed through XRD, and the change law of the dislocation density was revealed under the action of different process parameters. Therefore, the macro and micro effect mechanism of process parameters on geometric dimensions was verified, and then the control method of the geometric dimension was obtained in belt-heated incremental sheet forming.

Optimum heating time for warm forming of AA7075 aluminum alloy in T6 condition

Optimum heating time for warm forming of AA7075 aluminum alloy in T6 condition

Chelating agent stimulated LDH post-treatment of PEO coated AA2024

Layered double hydroxides (LDHs) are well known and broadly investigated on bare aluminum alloys, but not on PEO treated aluminum where source of aluminum ions is restricted. The additions of the chelating agents were tested in this work to stimulate the LDH formation on PEO (plasma electrolytic oxidation) coated aluminum alloy AA2024. 1,3-diamino-2-hydroxipropane-N,N,N’,N’-tetraacetic acid (DHPTA) was identified as the most effective one among tested additives. Its performance in terms of LDH growth stimulation was investigated. The DHPTA additive provides an increase of the pH of the LDH synthesis compared to previously known methods to achieve hydration of aluminum oxide from PEO as the initial stage of PEO etching, as well as the formation of soluble complex compounds of Zn-DHPTA, necessary for the formation of ZnAl LDH. The process of LDH formation was also followed by intercalation of DHPTA ions into LDH galleries. It was shown that LDH was formed both on the surface and insight the pores of parental PEO coating. Moreover, it imparted lubricating properties to the hybrid coating. Finally, PEO-LDH coating demonstrated higher corrosion resistance and long-term stability comparing to the PEO coated aluminum alloy.

General Method for Fitting Kinetics from the SECM Images of Reactive Sites on Flat Surfaces.

Scanning electrochemical microscopy (SECM) is a technique for imaging electrochemical reactions at a surface. The interaction between electrochemical reactions occurring at the sample and scanning electrode tip is quite complicated and requires computer modeling to obtain quantitative information from SECM images. Often, existing computer models must be modified, or a new model must be created from scratch to fit kinetic parameters for different reactive features. This work presents a method that can simulate the SECM image of a reactive feature of any shape on a flat surface which is coupled to a computer program which effectuates the automated fitting of kinetic information from these images. This fitting program is evaluated along with several methods for estimating the shapes of reactive features from their SECM images. Estimates of the reactive feature shape from SECM images were not sufficiently accurate and produced median relative errors for the surface rate constant that were >50%. Fortunately, more precise techniques for imaging the reactive features such as optical microscopy can supply sufficiently accurate shapes for the fitting procedure to produce accurate results. Fits of simulated SECM images using the actual shape from the simulation produced median relative errors for the surface rate constant that were <10% for the smallest reactive features tested. This method was applied to the SECM images of aluminum alloy AA7075 which revealed diffusion-limited kinetics for ferrocene methanol reduction over inclusions in the surface of the alloy.

Comparison between Mechanical Properties and Joint Performance of AA 2024-T351 Aluminum Alloy Welded by Friction Stir Welding, Metal Inert Gas and Tungsten Inert Gas Processes.

The aim of this work is to study joining Al 2024-T3 alloy plates with different welding procedures. Aluminum alloy AA 2024-T351 is especially used in the aerospace industry. Aluminum plates are welded by the TIG and MIG fusion welding process, as well as by the solid-state welding process, friction stir welding (FSW), which has recently become very important in aluminum and alloy welding. For welding AA2024-T35 with MIG and TIG fusion processes, the filler material ER 4043-AlSi5 was chosen because of reduced cracking. Different methods were used to evaluate the quality of the produced joints, including macro- and microstructure evaluation, in addition to hardness and tensile tests. The ultimate tensile strength (UTS) of the FSW sample was found to be 80% higher than that of MIG and TIG samples. The average hardness value of the weld zone of metal for the MIG- and TIG-produced AA2024-T3511 butt joints showed a significant decrease compared to the hardness of the base metal AA2024-T351 by 50%, while for FSW joints, in the nugget zone, the hardness is about 10% lower relative to the base metal AA2024-T3511.

Experimental investigation of friction stir welding with special spherical ball shoulder different probe tools and parameters for enhanced material properties of AA2219 aluminium alloy

This research investigates the impact of unique spherical ball shoulder enhancement tool pin configurations on the friction stir welding (FSW) of AA2219 aluminum alloy under various parameters. FSW was performed using three different pin shapes: square, hexagonal, and octagonal. Testing samples were prepared using an L9 orthogonal array layout with varying welding parameters. The material behavior in the three distinct weld zones was evaluated for each pin configuration. Results indicated superior microhardness values in the heat-affected zone (HAZ) and thermo-mechanically affected zone (TMAZ) compared to the weld nugget zone. Elemental composition analysis of the TMAZ revealed significant differences, highlighting the influence of thermal stress and material behavior due to the tool pin and shoulder configuration. The square-headed tool demonstrated improved tensile strength and microhardness. Optimal welding performance was achieved with a spindle speed of 1000 RPM, a travel speed of 25 mm/min, and a tilt angle of 3°. Variations in Cu content in the TMAZ and HAZ underscored localized modifications within the material structure, driven by the spherical ball spinning effects on the shoulder. Tensile tests showed that welds made with the square pin consistently exhibited higher tensile strength compared to those made with hexagonal and octagonal pins.

Grain Refinement and Texture Evolution of an AA5052 Aluminum Alloy during Flow Forming

Grain Refinement and Texture Evolution of an AA5052 Aluminum Alloy during Flow Forming

Enhancing strength and ductility of graphene and ZrO2 nanoparticles hybrid reinforced AA2024 composite fabricate by laser powder bed fusion

The AA2024 aluminum alloy is difficult to manufacture by laser powder bed fusion (L-PBF) due to its crack sensitivity. This work introduces a novel crack-free graphene nano-platelets (GNPs) and ZrO2 nanoparticles hybrid-modified AA2024 alloy suitable for laser powder bed fusion (L-PBF). The columnar-to-equiaxed transformation caused by nanoparticles-inducing nucleation sites eliminates the cracks. A bimodal microstructure consists of coarse columnar grains and ultrafine equiaxed grains, which are formed in the as-built composites. Compared with the L-PBF prepared AA2024 alloy and 1 wt% ZrO2/AA2024 composite, the (0.2 wt% GNPs + 1 wt% ZrO2)/AA2024 composite exhibit the highest tensile strength of 382 MPa and elongation of 16 %. The introduction of GNPs and ZrO2 nanoparticles provide dual increment in both tensile strength and ductility compared with single ZrO2 nanoparticles modified AA2024. Following further T6 heat treatment, the tensile strength increased significantly to 624 MPa, but the elongation decreased dramatically to 5.6 %. In-depth analysis was provided of the strength and ductility improvements induced by GNPs/ZrO2 nanofiller in this investigation.

Novel numerical approach toward hybrid nanofluid flow subject to Lorentz force and homogenous/heterogeneous chemical reaction across coaxial cylinders

The combination of AA7075 and Ti6Al4V aluminum alloys provides an effective balance of endurance, corrosion resistance, and lightness. Some potential applications include aviation components, marine structures with anti-corrosion characteristics, surgical instruments, and athletic apparel. Therefore, the hybrid nanofluid (Hnf) consists of aluminum alloys (AA7075-Ti6Al4V), water (50%), and ethylene glycol (EG-50%) in the current analysis. The Hnf flow subject to heat radiation and Lorentz force is studied through coaxial cylinders. In addition, the flow has been observed under the impacts of homogeneous-heterogeneous (HH) chemical reaction and exponential heat source/sink. The modeled equations (continuity, momentum, HH, and heat equations) are renovated into the non-dimensional form through the similarity approach, which are further numerically computed by employing the ND-solve technique coupling with the shooting method. It can be noticed from the graphical results that the flow rate of Hnf drops with the rising effect of porosity and magnetic field parameters. The addition of AA7075-Ti6Al4V nanoparticles (NPs) also reduces the fluid temperature and velocity profile. Furthermore, the concentration distribution diminishes with the flourishing effect of HH parameters.

Optimization of Ultrasonic-Assisted Incremental Sheet Forming.

Implementing the ultrasonic vibration-assisted incremental sheet-forming (UISF) process has been proven to significantly reduce the forming force, improve the surface quality, and enhance the accuracy of the sheet-forming process. However, such effectiveness has primarily focused on easily deformable materials (such as AA1050 and AA1060 aluminum alloys) and small step-down sizes (from 0.3 mm to 0.5 mm). To further enhance the process, it is crucial to study larger step-down sizes and harder materials. In this study, a series of UISF experiments were conducted, with step-down sizes ranging from 0.5 mm to 1.5 mm and feed rates ranging from 200 mm/min to 1200 mm/min. The influence of ultrasonic vibration on the effectiveness of force reduction and the optimal operation parameters was experimentally tested. Forming aluminum alloy AA5052, a difficult-to-deform material with two thicknesses of 0.5 mm and 1.0 mm, indicates that the axial force Fz and the tool movement resistance force Fy tend to decrease significantly with ultrasonic vibration assistance. Optimal equations for force reduction Fz and Fy have been developed for plate thickness based on the step-down size and feed rate. The optimal results show that for 1.0 mm thickness, reductions in Fz and Fy can reach 58.73% and 69.17%, respectively, and that of 64.17% and 71.98%, respectively, for 0.5 mm thickness.

Optimization of process parameters of metal inert gas welding process on aluminum alloy 6063 pipes using Taguchi-TOPSIS approach

To achieve a superior-quality weld, it is imperative to employ the appropriate welding parameters. In this study, the Taguchi-based technique for order of preference by similarity to ideal solution (TOPSIS) method has been used to improve the welding parameters such as current, voltage, and travel speed for metal inert gas (MIG) welding on the AA6063 aluminum alloy. Experiments have been performed to assess the hardness and strength characteristics of the joints. The assignment of the specimen was determined by the TOPSIS algorithm, which considers the specimen's performance score. The analysis of variance (ANOVA) approach was performed to identify the parameter with the highest significance level. A mathematical model has been established using a regression equation to establish a relationship between performance scores' signal-to-noise (S/N) ratio and process parameters. The optimal parameters for the butt joint welded using the MIG technique were determined to be a current of 120 A, a voltage of 20 V, and a travel speed of 3 cm/min. The ANOVA findings reveal that the current factor exhibits the highest level of statistical significance, accounting for 63 % of the observed variation. This was followed by voltage and travel speed, which contributed 24 % and 10.3 %, respectively. To ensure the validity of the findings, a confirmatory experiment was conducted using parameters optimized for analysis. The results of the confirmation indicate a strong alignment with the approach that was implemented.

EVALUATION OF SUPERPLASTIC PROPERTIES OF AA7075 ALUMINUM ALLOY SHEET FABRICATED BY THERMOMECHANICAL PROCESSING

The superplastic forming (SPF) process is the large plastic deformation ability of metals and alloys. However, SPF ability can only be achieved under certain conditions including ultrafine grain (UFG) microstructure, high temperature, and very small strain rate. In this work, the high-strength aluminum alloy AA7075 was selected for the experimental process due to its outstanding industrial application. First, thermomechanical processing (TMP) is performed to create a fine stable grain size for the studied alloy. The UFG microstructure was obtained after TMP with an average grain size of about 10 μm. Subsequently, the tensile test method and the bulging free-forming (BFF) method were used to evaluate the superplastic properties of the AA7075 aluminum alloy sheet fabricated by TMP. These two methods are performed at temperatures of 500ºC and 530ºC with strain rates from 10-4 (s-1) to 10-3 (s-1). The relative elongation and the strain rate sensitivity are the evaluation criteria. At the temperature of 530ºC and strain rate of 10-3 (s-1), the maximum relative elongation and flow stress were achieved at 280% and 7.6 MPa, respectively. The value of the coefficient m ranges from 0.3 to 0.6. The obtained results confirm the SPF properties of the aluminum alloy sheet AA7075.