AA6061 Alloy Research Articles

Life cycle assessment of direct recycling hot press forging of aluminium AA7075 metal matrix composite

The primary objective of this research is to investigate the process of direct recycling of AA7075 aluminium alloy, which is extensively utilised in the aerospace and flight sectors due to its exceptional strength and lightweight characteristics. Alumina (Al2O3) is used as a reinforcing agent and the effect of hot press forging (HPF) parameters on the mechanical characteristics and surface integrity of the metal matrix composite (MMC) constructed of AA7075 alloy with 1% Al2O3 has been studied. Furthermore, the utilisation of an integrated life cycle assessment (LCA) approach is implemented to assess the environmental impacts and economic expenses associated with the recycling of aluminium via high-pressure forming for both the metal matrix composite and AA7075 alloy. Response surface methodology (RSM) is applied to ascertain the optimal parameters for high-performance filtration. The findings suggest that employing a forging temperature of 532.34 °C and a holding time of 60 min produces favourable results. When comparing the characteristics of the MMC and recycled aluminium, it can be observed that they both demonstrate similar essential process attributes. The utilisation of HPF in conjunction with the Multi-Material Composite has the potential to yield a reduction of up to 24.97% in Global Warming Potential (GWP). This research demonstrates the efficacy of HPF as a viable approach for environmentally conscious and economically efficient recycling of AA7075 aluminium scrap, thereby improving product performance and promoting sustainability.

Impact of hot rolling temperature on the mechanical properties and microstructural evolution of hot/cold-rolled AA5083 with Sc and Zr microalloying

The impact of hot rolling temperature on the microstructure evolution and mechanical properties of hot/cold-rolled AA5083 alloy containing Sc and Zr was studied. The results revealed that low hot-rolling temperatures (LHRT: 400–425 oC) resulted in superior tensile properties compared to high hot-rolling temperatures (HHRT: 500–525 oC). The yield strength (YS) of the LHRT samples reached 450 MPa in the H18-temper and 291 MPa in the O-temper, which was respectively 20% and 39% higher relative to the HHRT samples. Microalloying with Sc/Zr and two-step homogenization promoted the formation of dispersed particles in the form of Mn-dispersoids and nanosized Al3(Sc,Zr) precipitates. The rolling temperature was found to have a profound impact on the characteristics of these dispersed particles and on the recrystallization resistance. The HHRT caused the coarsening of both dispersed particles during rolling. The LHRT preserved the deformed elongated grain structure due to a stronger retardation of recovery and recrystallization during hot rolling and post-annealing. The strengthening mechanisms of the Mn-dispersoids and Al3(Sc,Zr) precipitates were quantitatively analyzed based on particle characteristics. The predicted YS contributions in the O-temper were in good agreement with the measured YS difference between the LHRT and HHRT samples.

Optimization of wire electrical discharge machining parameters of AA6063/Al2O3 nanocomposite processed by multi axial forging using Taguchi technique

AbstractThe aluminium based matrix composites have excellent mechanical properties to use in automobile, aerospace, aviation, and military industries. The aluminium based matrix composite possesses desired characteristics like specific strength, excellent rigidity and wear resistance. The stir casting technique was used to fabricate the nanocomposite of AA6063 alloy reinforced with 5 weight % nano aluminium oxide particulate. To improve the microhardness of as cast and aluminium based nanocomposites, multiaxial forging was performed up to three passes for grain refinement. Wire electrical discharge machining was used to machine both as cast and “AA6063/Al2O3” (zero and three multi axial forging pass). The machining characteristics of samples were statistically examined using the Taguchi technique. The material removal rate in three multiaxial forging pass nanocomposite sample increased as peak current increases. However, increasing the pulse off time resulted in the lowest material removal rate. The surface roughness was found to be higher in the nanocomposite sample in comparison to as cast. The machining on nanocomposite multiaxial forged sample has a greater impact as compared to as cast. After machining, scanning electron microscopy was used to examine the surface morphology. The presence of different elements in the castings was validated using energy dispersive X‐ray spectroscopy.

A comparative study of machine learning in predicting the mechanical properties of the deposited AA6061 alloys via additive friction stir deposition

AbstractAdditive friction stir deposition (AFSD) provides strong flexibility and better performance in component design, which is controlled by the process parameters. It is an essential and difficult task to tune those parameters. The recent exploration of machine learning (ML) exhibits great potential to obtain a suitable balance between productivity and set parameters. In this study, ML techniques, including support vector machine (SVM), random forest (RF) and artificial neural network (ANN), are applied to predict the mechanical properties of the AFSD‐based AA6061 deposition. Expect for the stable parameters (temperature, force and torque) in situ monitored by the self‐developed process‐aware kit during the AFSD process and the other factors (rotation speed, traverse speed, feed rate and layer thickness) are also set as input variables. The output variables are microhardness and ultimate tensile strength (UTS). Prediction results show that the ANN model performs the best prediction accuracy with the highest R2 (0.9998) and the lowest mean absolute error (MAE, 0.0050) and root mean square error (RMSE, 0.0063). Furthermore, analysis suggests that the feed rate (24.8%/24.1%) and layer thickness (25.6%/26.6%) indicate a higher contribution that affects the mechanical properties.

Fabrication and Sliding Wear Characterization of Eggshell Particulate Reinforced AA6061 Alloy Metal Matrix Composites

In this work, AA6061 aluminum alloy composites reinforced with industrial wastes, i.e., eggshell particles are fabricated. The stir casting technique was used to fabricate the Al6061 metal matrix composites. The AA6061 matrix contains 3, 5, and 7 wt.% eggshell particles as reinforcement. Mechanical characterization i.e., hardness, toughness, and tensile strength was examined of the eggshell particle-reinforced composites. According to the experimental findings, adding eggshell particles significantly increased the material's hardness, tensile strength, and toughness. Moreover, the sliding wear resistance improved by adding eggshell particles as reinforcement. ANNOVA results predict that sliding velocity and load are the dominant factors for the sliding wear of composites.

Modeling of thrust force and torque in drilling aluminum 7050

Abstract The aluminum AA7050 alloy has high toughness and high strength. Despite the high machinability of the AA7050 alloy, hole quality can vary according to tool geometry and drilling parameters. This study investigated the effects of different cutting parameters and three different drill point angles on thrust force and torque. Numerical analyses for thrust force and torque were performed using the finite element method. The lowest thrust force and the highest torque were obtained with the drill at 130° drill point angle, while the highest cutting force and lowest torque were obtained with the drill at 118° drill point angle. There is an average difference of 5.37 and 6.9 % between the experimental and analysis values for thrust forces and torque, respectively, and the applicability of the finite element model has been proven. In the last part of the study, thrust force and torque are modeled with artificial neural networks. The statistical accuracy (R 2) values for the learning and testing values in the thrust force of the equation are 0.997797 and 0.995739, respectively. Torque’s learning and testing accuracy values are 0.987247 and 0.937909, respectively. The obtained equations have a high accuracy rate.

Laser butt welding of AA7075 aluminium alloy and Ti6Al4V titanium alloy using a Cu interlayer

Laser welding of AA7075 and Ti6Al4V, two very different aerospace alloys, was performed with a copper (Cu) interlayer to avoid the brittle Ti–Al intermetallics. The joint was formed owing to the diffusion of Cu into the AA7075 alloy and limited diffusion in Ti6Al4V alloy, followed by eutectic formation at the AA7075/Cu interface. Microstructural and energy dispersive spectroscopy (EDS) analyses of the joint area revealed the presence of eutectic phases at grain boundaries inside the AA7075 fusion zone (FZ). An interfacial Cu3Ti2 phase formed at the solid-state Ti6Al4V/Cu interface. A robust and sound joint was achieved through the effective utilisation of Cu as an interlayer.

A Study on the Optimization of Nano-B4C Content for the Best Wear and Corrosion Properties of the Al-Based Hybrid Nanocomposites

This investigation is dedicated to producing hybrid nanocomposites based on AA2024, achieved through the utilization of powder metallurgy methods encompassing mechanical milling and hot pressing. The research focused on studying how changes in B4C content influence the mechanical, wear, and corrosion behavior of AA2024/h-BN/B4C hybrid nanocomposites. The findings revealed that as the B4C content increased, the relative density values decreased, and higher porosity values were observed in the hybrid nanocomposite samples. Among the tested samples, the hybrid nanocomposite with 4 wt% B4C exhibited the most favorable properties. It demonstrated significantly higher hardness and ultimate tensile strength compared to AA2024 matrix alloy, with values of 161 HB and 372 MPa, respectively. In contrast, the matrix alloy showed hardness and ultimate tensile strength values of 105 HB and 237 MPa, respectively. Furthermore, the wear resistance of hybrid nanocomposite with 4 wt% B4C displayed approximately 14 times greater wear resistance under 40 N load compared to the unreinforced AA2024 matrix alloy. The corrosion test results have revealed that the corrosion resistance of the hybrid nanocomposite reinforced with 4wt% B4C is nearly 47% higher compared to the corrosion resistance of the unreinforced AA2024 alloy. This nanocomposite exhibits the highest polarization resistance of 5.21 Ω.cm2.

Microstructure Evolution and Mechanical Properties of Multilayer AA6061 Alloy Fabricated by Additive Friction Stir Deposition

Microstructure Evolution and Mechanical Properties of Multilayer AA6061 Alloy Fabricated by Additive Friction Stir Deposition

Microstructure, microhardness and mechanical behavior of dissimilar AA7075/AA6061 alloys under friction stir welding

Friction stir welding (FSW) of dissimilar AA6061 and AA7075 aluminum alloys faces challenges such as an unclear forming mechanism and low welding efficiency. In order to improve welding efficiency and elucidate the variations in metallography, Microhardness, and mechanical properties of dissimilar alloy FSW joints, this article designed FSW experiments using the Taguchi method with welding speeds ranging from 600 to 1000 mm/min. We studied the relationship between material mixing and welding defects through macroscopic metallography, microscopic metallography, and Microhardness, while the impact of welding parameters on the microstructure and properties was evaluated. The results show that void defects do not exist in dissimilar alloy FSW joints, and the Microhardness changes are “U” and “W” shaped. Material mixing played a decisive role in determining the microstructure and properties of dissimilar aluminum alloy FSW joints, with increased rotational speed enhancing material flow. The order of influence on the mechanical properties of the joint was found to be plunge depth, welding speed, and rotational speed. Under the conditions of 1000 mm/min, 2400 rpm, and 0.25 mm, the yield strength (YS) and ultimate tensile strength (UTS) of the dissimilar alloy FSW joints reached 87.3% and 73.4% of the AA6061-T6 alloy, respectively.

Tailoring precipitate distribution in 2024 aluminum alloy for improving strength and corrosion resistance

For the traditional peak-aged (PA) AA2024 alloy, the formation of large S-phase precipitates within the grains, wide precipitate-free zones (PFZs) near the grain boundaries (GBs), and continuous distribution of grain boundary precipitates (GBPs) can be observed. As a result, the PA alloy exhibits relatively high strength but poor corrosion resistance. However, with the application of cyclic plasticity treatment, high-density 1–2 nm clusters form within the matrix, and no PFZs form near GBs. In this study, this treatment yields the optimal balance between strength–elongation characteristics and corrosion resistance. By combining cyclic plasticity and ageing heat treatment with different heating rates, the nanoscale clusters play a crucial role as heterogeneous nucleation sites, resulting in the formation of finer and higher number density of S precipitates within the matrix. Additionally, the presence of these clusters reduces the formation of GBPs and minimizes the width of PFZs. Consequently, compared to the traditional PA sample, this approach achieves a significantly higher yield strength (increased by 46 %) and ultimate tensile strength (increased by 18 %), along with superior corrosion resistance. Although the influence of ageing heat treatment with different rates on mechanical properties is not significant, it notably affects the formation of GBPs and corrosion resistance. Specifically, a slower heating rate leads to an increase in the spacing between adjacent GBPs, resulting in improved corrosion resistance. In summary, cyclic strengthening, as a novel method for alloy strengthening, when combined with ageing heat treatment, modulates the distribution of S precipitates within the matrix and GBs. This optimization maximizes the effects of precipitation strengthening and breaks the inverse relationship between strength and corrosion resistance.

Generative adversarial network (GAN) enabled Statistically equivalent virtual microstructures (SEVM) for modeling cold spray formed bimodal polycrystals

Image-based micromechanical models, necessary for the development of structure-property-response relations, are far from mature for complex microstructures with multi-modal distributions of morphological and crystallographic features, such as those occurring with cold spray-formed (CSF) aluminum alloys. These materials have a bimodal polycrystalline microstructure composed of recrystallized ultra-fine grains (UFGs) and deformed coarse grains (CGs) within prior particles. A prime reason is the lack of robust approaches for generating statistically equivalent virtual microstructures (SEVM) capturing the statistics of characteristic morphological and crystallographic features, such as grain size, crystallographic orientations, and misorientations. This paper introduces an approach, strategically integrating Generative Adversarial Network-based approaches for producing bimodal CSF AA7050 alloy microstructures, with the synthetic microstructure builder Dream3D for packing prior particles with CGs having statistically equivalent morphological and crystallographic descriptors to electron backscatter diffraction (EBSD) maps. An efficient finite element (FE) simulation approach is developed for the SEVMs to generate local and overall response functions through the creation of sub-volume elements (SVEs).

Tribological and impact- toughness performance of friction stir processed AA7075

This technical investigation used friction stir processing to modify the AA7075- T6 alloy and aimed to analyze the wear and impact toughness properties of the modified surfaces. Effects of the input parameters of the friction stir process (FSP) were also studied. Initially, the as-received AA-7075 alloy was processed using FSP at the selected parameters to get defect-free processed specimens. Next, the microstructures of the base alloy and processed regions were examined through an optical microscope. Then, the impact toughness was measured using the Charpy test, and sliding wear behavior was evaluated on a pin-on-disc tribo-tester. The processed samples’ average impact energy was better than the base material’s. Also, their wear property, i.e., coefficient of friction and weight loss, were more promising than the parent metal. Finally, fractography of the fractured Charpy test sampleswas done to study the fracture behavior; andSEM micrographs and 2D profiles of wear tracks were analysed to examine the wear behaviour properly.

Grey-Taguchi Approach for Optimizing FSW Parameters in Joining AA6262 and AA5083 Alloys

T his study concentrates on the friction stir welding (FSW) joining of dissimilar AA6262 and AA5083 plates. Four input parameters, namely tool rotational speed (TRS), welding speed (WSP), tool tilt angle (TTA), and pin depth (PDP) are chosen to analyze the output responses of tensile strength (UTS), hardness (HBN), and wear rate (WTR) in welding. The primary objective is to optimize the variables of the FSW process for AA6262 and AA5083 alloys using a combination of Taguchi and Grey Relational Analysis (GRA) methods, while also comprehending the correlations among process variables through the application of these two methods. Utilizing the Taguchi approach, L27 orthogonal array is constructed for conducting FSW experiments. After this, the multi-objective optimization challenge is streamlined into a single-objective optimization task by leveraging the grey relational degree. The significance and impact of the distinct variables are elucidated through the application of Analysis of Variance (ANOVA). Confirmation tests and predictive analysis are performed to validate the optimal variables, which are then compared against the acquired outcomes. The results highlight the welding speed as the paramount parameter, exerting substantial influence over the output responses of the welds in contrast to the other variables under examination. The application of the Grey-Taguchi methodology yields enhancements in Tensile Strength (245.23 MPa) and Hardness (99.2 Hv), while concurrently decreasing the Wear Rate (0.00456 m3/Nm). Furthermore, the Grey Relational Grade exhibits an advancement of 0.1312. These findings collectively signify an increased operational efficiency in the welding process, particularly for dissimilar alloys.

Investigations on surface properties and surface morphology in dissimilar joining of WE43 and AA-7075 alloy

Joining Mg-Al hybrid structures through fusion welding often yields uneven weld surfaces with an excessive density of intermetallic compounds (IMCs). To mitigate this, solid-state welding methods were employed. In this investigation, Friction Stir Welding (FSW) was used to join WE43 and AA-7075 alloys. Optical microscopy (OM) and scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS) were used to evaluate the microstructural properties of the welded surfaces. Surface characteristics, including wear, microhardness, and corrosion, were assessed through wear testers, micro-hardness testers, and potentio-dynamic polarization tests. The results indicated a reduction in IMC content. These findings enhance our understanding of how ambient air and DM-water, as variable process parameters, influence the surface properties, strength, and morphology of Mg-Al dissimilar joints.

Evaluation of the Structural Characteristics and Wear Performance of the Novel ECAR-Processed AA5083 Alloy

Evaluation of the Structural Characteristics and Wear Performance of the Novel ECAR-Processed AA5083 Alloy

Modeling and Experimental Investigation of the Impact of the Hemispherical Tool on Heat Generation and Tensile Properties of Dissimilar Friction Stir Welded AA5083 and AA7075 Al Alloys.

This study investigated the effect of a hemispherical friction stir welding (FSW) tool on the heat generation and mechanical properties of dissimilar butt welded AA5083 and AA7075 alloys. FSW was performed on the dissimilar aluminum alloys AA5083-H111 and AA7075-T6 using welding speeds of 25, 50, and 75 mm/min. The tool rotation rate was kept constant at 500 rpm. An analytical model was developed to calculate heat generation and temperature distribution during the FSW process utilizing a hemispherical tool. The experimental results were compared to the calculated data. The latter confirms the accuracy of the analytical model, demonstrating a high degree of agreement. Sound FSW dissimilar joints were achieved at welding speeds of 50 and 25 mm/min. Meanwhile, joints created at a welding speed of 75 mm/min exhibited a tunnel-like defect, which can be attributed to the minimal heat generated at this particular welding speed. At a lower welding speed of 25 mm/min, a higher tensile strength of the dissimilar FSWed joints AA5083 and AA7075 was achieved with a joint efficiency of over 97%.

The effect of heat treatment on the microstructure and mechanical properties of multilayer AA6061 alloy fabricated by additive friction stir deposition

Multilayer AA6061 aluminum alloy components were successfully fabricated by the additive friction stir deposition (AFSD). The effect of heat treatment on the microstructure and mechanical behavior of the aluminum alloy components was studied. Due to dynamic recrystallization, AFSD AA6061 sample presented a 93.2% average reduction in grain size as compared to base material (BM) (∼ 39.13 µm). Abnormal grain growth was observed in the AFSD-HT sample, and the average grain size of AFSD-HT sample was 592 µm. There was an occurrence of texture formation in the AFSD and AFSD-HT samples, mainly due to severe shear deformation during AFSD process. The maximum texture density of AFSD-HT sample was increased to 17.84. In the BM sample, apart from the β" strengthening phases, hard-brittle intermetallic compounds of Al5FeSi aggregated along the boundaries of the coarser grains. Due to the high temperature generated during the process of AFSD, the β" strengthening phases dissolved into the matrix, and significantly reduced the strength and hardness. After heat treatment, the AFSD AA6016 alloy recovered 18% of its strength at a loss of 2.8% ductility. High density β" strengthening phases precipitated, resulting in increased strength and hardness.

Effect of Al–Fe–Mn–Si particle characteristics on the growth morphology and corrosion resistance of anodic oxide film on AA 3003 aluminium alloy

This study examines the impact of Al–Fe–Mn–Si particle characteristics in AA3003 alloy on the morphology and resistance of anodic oxide films against corrosion. The results show that low-silicon-content Al–Fe–Mn–Si particles oxidise simultaneously with the matrix to form a discontinuous porous oxide film, and complex small pores are formed in the porous layer; although high-silicon-content Al–Fe–Mn–Si particles have the same oxidation rate as the alloy matrix, the growth of the oxide film is hindered by unoxidised particles in the porous layer due to the influence of particle size and chemical composition, resulting in uneven growth of the oxide film and ultimately causing defects such as enlarged pores and cracks. A mechanism model for Al–Fe–Mn–Si particles affecting the morphology of oxide film growth was established. Electrochemical test results show that compared with the oxide film of the high-silicon-content alloy, the oxide film of the low-silicon-content alloy has better corrosion resistance performance, with a corrosion potential of −0.512V (compared with −0.836V for the high-silicon alloy) and a corrosion current density of 3.34 × 10−8A/cm2 (compared with 9.614 × 10−7 A/cm2 for high-silicon alloy). The barrier layer attained an elevated impedance value and exhibited self-repairing capabilities.

FE parametric evaluation of macro-to-microscale dry milling for sustainable manufacturing of aerospace alloys

Micro-end-milling of energy-efficient materials has gained prime significance in advanced manufacturing due to their excellent machining characteristics. Numerous experimental and numerical studies have been conducted to establish the optimum parameters of the micro-end-milling process. Because of the complex interaction at the tool-burr interface that involves high material strain rates, this study investigated an extensive parametric sensitivity analysis to evaluate the reliability of numerical simulations. The numerical simulations of AA2024 and Ti6Al4V alloy micro-end-milling are performed in Abaqus/Explicit using the thermo-viscoelastic Johnson-Cook damage model. The parametric sensitivity analysis of both materials is compared, and the burr morphologies are analyzed with changing material characteristics. Tool-burr interface temperature, cutting reaction forces, material plastic strain, and stresses are evaluated to analyze the effect of the change in material characteristics with cutting parameters. Computations are performed at different cutting speeds, tool edge radii, cutting feeds, and contact friction to analyze their effect on chip stress, temperature, material strain, and the tool's thrust force. Feed and contract friction demonstrated pronounced effects on the chip-tool interface temperature compared to the contact friction for both types of materials. The computational results are verified with the experimental data.