Alloy AA Research Articles

A Comprehensive Investigation of BN and VC Reinforcements on the Properties of FSP AA6061 Composites

This present study investigated the impact of incorporating boron nitride (BN) and vanadium carbide (VC) reinforcements on various properties of friction stir processed (FSP) AA6061 alloy composites, focusing specifically on grain structure, thermal conductivity, electrical conductivity, and compressive strength. The findings indicate that VC more effectively refines the grain structure of the AA6061 alloy during FSP compared to BN. The inclusion of BN particles in the metal matrix composites resulted in a decrease in both thermal and electrical conductivity. In contrast, the addition of VC particles led to an increase in both thermal and electrical conductivity. The AA6061/VC composite material exhibited the highest thermal conductivity among all composites tested. The electrical conductivity of the hybrid-composite AA6061/30%BN+70%VC showed a slight reduction, measuring only 2.8% lower than the base alloy AA6061. The mono-composite AA6061/VC exhibited a marginal decrease in thermal conductivity, with a measured value only 7.5% lower than the conventional alloy AA6061. However, the mono-composite AA6061/BN displayed a more significant decline, exhibiting a loss of 14.7% and 13.9% in electrical and thermal conductivity, respectively. The composite material comprising 30% BN and 70% VC reinforcement demonstrated the highest compressive strength compared to all other tested composites. The observed percentage enhancement in the mechanical properties of mono and hybrid composites, compared to the parent AA6061 alloy, ranged from 17.1% to 31.5%.

Influence of Clad Layer Thickness of Aluminium Alloy by Friction Surface Cladding Process

Friction Surface Cladding (FSC) is a process that enables the deposition of clad material on a substrate through a hollow rotating tool to create thin clad layers at sufficiently high temperatures. Heat is produced during the cladding process by friction at the tool-clad layer and the substrate. This study focus on the influence of clad layer thickness of aluminium alloy AA2024 at the control process temperature around 300℃ to 350℃. The material used is AA2024-T4 for the clad layer and AA2024-T351 for the substrate. A thermal model is built using COMSOL Multiphysics 6.0 and Heat Transfer in Solid (ht) with time-dependent study is used to study the heat transformation as well as optimize the rotational speed at different clad layer thicknesses. The major finding in this study indicates that the heat generated is proportional to the clad layer thickness. The highest heat transformation can be seen at the cladding region between the cladding rod and the substrate and the temperature reaches a maximum of 333.95℃.

Effect of TiC nano-treating on the fluidity and solidification behavior of aluminum alloy 6063

Wrought aluminum alloy AA 6063 is known for its favorable mechanical properties, corrosion resistance, and weldability in high-performance applications. Nonetheless, its limited fluidity hinders the cost-effective production of intricate structures through economical casting processes. To address this, a small fraction of TiC nanoparticles were dispersed into the AA 6063 melt to enhance its fluidity, eliminate hot cracking, and improve casting surface quality. Further investigation indicates that nanoparticles contribute to gradual latent heat release, grain growth restriction, and improved molten alloy wettability. The results demonstrate the potential of the emerging nano-treating technology in making traditionally difficult-to-cast alloys viable for low-cost casting operations to deliver products with enhanced high performance for numerous applications.

Development of polyamide 6‐graphene oxide nanocomposite and direct‐joining with aluminum alloy for lightweight engineering applications

AbstractLightweight polyamide composites and structures have been widely studied and employed in several industrial sectors. In this study, the development of a nanocomposite of polyamide 6 and graphene oxide (PA6‐GO) by melt‐compounding and the joining with aluminum alloy AA6061 through direct‐adhesion injection overmolding are addressed. PA6‐GO nanocomposite exhibited well‐dispersed thin (300 nm) GO platelets distributed within the PA6 matrix, which resulted in an increase of 21% in the tensile modulus and 16% in the yield stress for a filler loading of 0.5 wt%. PA6‐GO/AA6061 hybrid joints showed good mechanical anchorage through the complete filling of the polymer into micro‐scale grooves designed onto the metal surface, which ensured outstanding shear strength of 7.1 ± 1.0 MPa, comparable to other polyamide‐metal hybrid joints reported in the literature. This indicates that the processing routes and materials developed are promising for lightweight engineering applications.Highlights A PA6‐GO nanocomposite with enhanced tensile properties was developed. A joint of PA6‐GO and AA6061 with outstanding shear strength was obtained. Fast and efficient melt‐processing routes were employed. These materials are promising for lightweight engineering applications.

Characterization of friction stir-based linear continuous joining of aluminium alloy to structural polymer

Dissimilar continuous joining of lightweight metal alloys to structural polymer is a major manufacturing challenge, demanding feasible and reliable solutions. Through-slot extrusion joining (TSEJ) is a friction stir-based processing technique investigated in the manufacturing of continuous linear joints between aluminium alloy AA5754 overlapping structural polymer polyether ether ketone (PEEK). An intermediate rigid and thin titanium extrusion die protects the polymer locally from thermal degradation and promotes the formation of a continuous double hook-like feature of extruded aluminium into the polymer component along the joint path. The structure of the joint provides macro-mechanical interlocking between the joined components. A set of four tools, and other key process parameters, were investigated for process stability, tensile-shear strength, and microstructure. The best TSEJ condition is chosen for microstructural analysis via optical microscopy and scanning electron microscopy. Three distinct failure modes were identified. The best condition provided an average tensile-shear load of 110 kN/m. The tool position with bias toward the flow side of the extrusion slot shows to improve the strength of joints. The microstructural analysis along the interface of AA5754 to PEEK exhibits micro-mechanical interlocking, intercalated layers of these materials and adhesion as joining mechanisms.

Effect of process parameters on friction stir welding of aluminium alloy AA6082–T6 with an interlayer using response surface methodology

In the present study, the effects of variation of process parameters on the mechanical properties of friction stir welded A6082–T6 aluminium alloy joints with Zinc (Zn) interlayer are experimentally investigated. Four process parameters, viz. rotational speed, welding speed, interlayer thickness and tool pin diameter are selected to fabricate the Friction Stir Welding (FSW) joints. After filling the Zn particles into the gap maintained between the plates, FSW is performed using different process parameters. Thereafter, tensile and impact strength tests are performed to evaluate the performance of the joints. It is analyzed that the tensile and impact strength of the joints vary from 121 to 197 MPa and 6 to 17 J, respectively. Subsequently, mathematical models are developed using Response Surface Methodology (RSM) to predict the effect of FSW process parameters on the tensile and impact strength of joints. Analysis of Variance (ANOVA) is used to check the level and degree of direct effect of process variables on the tensile and impact strength of the joints. It is observed from the results that tool rotational speed is the most influential process parameter, which enhances the mechanical properties of FSW joints, whereas an increase in welding speed reduces the mechanical properties of the joints.

Electrochemical corrosion of aluminium alloy AA1050, processed by accumulative roll bonding

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Numerical Analysis of Recycled AA6061 Reinforced Alumina Oxide Undergoing Finite Strain Deformation Uniaxial Tensile and Taylor Cylinder Impact Tests

Recycling aluminum is a topic of high interest due to the global demand for aluminum-based products. This approach presents a great opportunity to address the environmental issues caused by the primary production of aluminum made from bauxite ore. In recent years, many researchers have explored the recycling of aluminum alloys, including reinforcement, to achieve better results and improve properties. However, there have been limited efforts to predict the deformation behaviour of such materials numerically. It is generally agreed that advancements in numerical analysis are important to accelerate progress and establish the application of newly developed materials. Therefore, this study aimed to numerically predict the deformation behaviour of recycled aluminum alloy AA6061 reinforced with Alumina Oxide, subjected to finite strain deformation of uniaxial tensile tests at different strain rates (6x10-1s-1 to 6x10-3s-1) and Taylor Cylinder Impact at different impact velocities (190ms-1 to 370ms-1) using the LS-DYNA simulation code. In this numerical analysis, a Simplified Johnson-Cook model is adopted and characterized. The simulation results, which were validated against published experimental data, showed good agreement, establishing appropriate numerical prediction capabilities for recycled aluminum alloys AA6061 reinforced with Alumina Oxide.

A Novel Method to Measure Equi-Biaxial Residual Stress by Nanoindentation

BackgroundThe accurate measurement of residual stresses (RS) is crucial for predicting the performance of mechanical components, as RS can significantly impact fatigue life, fracture, corrosion, and wear resistance. Different experimental methods were developed to measure RS, including non-destructive techniques. Among these methods, instrumented nanoindentation has emerged as a promising approach to assess equi- or non-equi-biaxial RS states. This technique analyzes variations in the mechanical response of indentation on a stressed or stress-free component to estimate residual stresses. Previous studies proposed different approaches to establish a relationship between RS and indentation parameters, such as contact area, peak load, mean contact pressure, indentation work, etc. However, the correlation between RS and peak load variation, commonly assumed to be linear, showed limitations, particularly when dealing with compressive RS.ObjectiveThe aim of this work is to develop a hybrid procedure, based on finite element (FEM) simulations and experimental analyses, to measure the equi-biaxial residual stresses. In particular, it is based on the analysis of the nanoindentation peak load variation generated by the presence of residual stresses on a component.MethodsTo overcome the limitations of the linear assumption, nanoindentation experiments were combined with finite element analyses (FEA). FEA simulations were used to estimate the correlation between RS and peak load variation, providing a better understanding of the non-linear relationship. A proper experimental setup, consisting in a stress generating jig, was designed and manufactured to perform nanoindentations on a sample, made by aluminium alloy AA 7050 T451, subjected to external mechanical stress with the aim to validate the FEA model. FEA and the digital image correlation (DIC) technique were also used to verify that the induced stress field was the expected one.ResultsObtained results revealed that the proposed method is a valid way to measure residual stresses. In fact, it offers an improved correlation between RS and peak load variation. In addition, by integrating nanoindentation experiments and FEA, a more accurate assessment of RS can be also achieved.ConclusionsThis research contributes to the development of a consistent methodology for RS measurement using instrumented nanoindentation.

Influence of synthesizing parameters on surface qualities of aluminium alloy AA5083/ CNT/MoS2 nanocomposite in powder metallurgy technique

Aluminium alloys are indispensable in all manufacturing industries, particularly mechanical engineering. The objective of this study is to enhance the mechanical, wear, and corrosion properties of aluminium alloy AA5083 by incorporating nanoparticles as reinforcements, thereby creating hybrid aluminium nanocomposites. The base material utilised in this study was AA5083, with the reinforcement nanoparticles selected as Carbon nanotubes (CNTs) and Molybdenum disulfide (MoS2) at concentrations of 5 % and 3 % respectively. Nanocomposites were fabricated using the Powder Metallurgy (PM) technique, employing specific contrasting parameters including Ball mill speed (280, 320, 360, and 400 rpm), Mixing time (20, 30, 40, and 50 min), Compaction pressure (300, 350, 400, and 450 MPa), and Sintering time (2, 3, 4, and 5 h). The operating parameters of powder metallurgy were assessed using the Design of Experiments (DOE) L16 Orthogonal Array, and their corresponding outcomes were analyzed. The results revealed that there is a significant correlation between the mixing time and microhardness of the nanocomposites. The wear and corrosion reduction rates had a significant impact on the sintering time parameter. The present study determined that the highest recorded microhardness value was 136 VHN, while the lowest observed rates of wear and corrosion were 0.192 mm3/m and 0.00081 mm/year, respectively. Scanning electron microscopy (SEM) images clearly depicted the presence of various structural defects, such as pits, cracks, delamination, voids, and cusps, in the wear and corrosion samples that exhibited reduced strength.

Phase-field simulation of the dendrite growth in aluminum alloy AA5754 during alternating current electromagnetic stirring laser beam welding

Electromagnetic stirring is known to promote material flow, reduce porosity, uniform elements distribution, and refine grain in laser beam welding (LBW), which enhances the applicability of LBW in various industries. In this study, a phase-field model of dendrite growth in AA5754 Al alloy electromagnetic stirring laser beam welding was established. The model considered the thermal electromagnetic Lorentz force resulting from the interaction between the electric field generated by the Seebeck effect and the magnetic field, as well as the temperature gradient and solidification rate of the solidification interface obtained from the computational fluid dynamics electromagnetic stirring LBW model. The variation rules of dendrite growth with different magnetic parameters and effects are analyzed. Comprehensively, the magnetic field promotes the solidification rate, thus promoting interfacial instability and a large magnetic flux density leads to a faster interface instability. The solidification rate as well as the temperature gradient affect the growth rate, and the accelerated growth caused by the solidification rate with a high frequency and a large magnetic flux density effectively inhibits the slow growth caused by the temperature gradient. The thermal electromagnetic Lorentz force is the main factor for the branch increment at low frequencies, while both thermal electromagnetic Lorentz force and temperature gradient increase the number of branches at high frequencies. The calculated average branch numbers considering various factors in the stable stage under different magnetic parameters were consistent with the results of the scanning electron microscope tests.

LCF behaviour of high strength aluminium alloys AA 6110A and AA 6086

The proposed research presents the comprehensive investigation of the Low Cycle Fatigue (LCF) behaviour of two high-strength aluminium alloys of series AA 6xxx: the conventional alloy AA 6110A and the newly developed alloy AA 6086. Both alloys were characterised in the as-cast condition after homogenisation, extrusion, and T6 heat treatment.The quasi-static strength and hardness of the aluminium alloy AA 6086 were found to be significantly higher if compared to the AA 6110A alloys, while the ductility was a little bit smaller. The LCF tests showed that the AA 6086 alloy is more suitable for the high-cycle fatigue regime. On the other hand, the engineering advantage of the AA 6110A alloy is only for low-cycle fatigue applications if less than 100 loading cycles are expected in the service life of the analysed structure. The fatigue cracks formed predominantly on the α-AlMnSi intermetallic particles in both alloys, and, during LCF tests, exhibited small crack propagation. The area of the fatigue crack growth was much smaller than the area of the forced fracture. At smaller amplitude strains the fatigue striations were present at the fracture surface, while, at higher amplitude strains, they were not present. The obtained experimental results represent a good basis for engineering design applications of the analysed alloys AA 6086 and AA 6110A.

Joining of dissimilar aluminum alloys AA5154 and AA2024 by cold roll bonding

Joining of dissimilar aluminum alloys AA5154 and AA2024 by cold roll bonding

Additive Friction Stir Deposition of AA7075-T6 Alloy: Impact of Process Parameters on the Microstructures and Properties of the Continuously Deposited Multilayered Parts

In the aircraft industry, the high-strength aluminum alloys AA7075 and AA2024 are extensively used for the manufacture of structural parts like stringers and skins, respectively. Additive manufacturing (AM) of the AA7075-T6 aluminum alloy via friction stir deposition to build continuously multilayered parts on a substrate of AA2024-T4 aluminum has not been attempted so far. Accordingly, the present work aimed to explore the applicability of building multilayers of AA7075-T6 alloy on a substrate sheet of AA2024-T4 alloy via the additive friction stir deposition (AFSD) technique and to optimize the deposition process parameters. The experiments were conducted over a wide range of feed rates (1–5 mm/min) and rotation speeds (200–1000 rpm). The axial deposition force and the thermal cycle were recorded. The heat input to achieve the AFSD was calculated. The AA7075 AFSD products were evaluated visually on the macroscale. The microstructures were also investigated utilizing an optical microscope and scanning electron microscope (SEM) equipped with an advanced EDS technique. As well as the presence phases, the mechanical performance of the deposited materials in terms of hardness and compressive strength was also examined. The results showed that the efficiency of the deposition process was closely related to the amount of heat generated, which was governed by the feeding rate, the rotational speed, and the downward force. AA7075 defect-free continuously multilayered parts were produced without any discontinuity defects at the interface with the substrate at deposition conditions of 1, 2, 3, and 4 mm/min and a constant 400 rpm consumable rod rotation speed (CRRS). The additively deposited AA7075-T6 layers exhibited a refined grain structure and uniformly distributed fragment precipitates compared to the base material (BM). The gain size decreased from 25 µm ± 4 for the AA7075-T6 BM to 1.75 µm ± 0.41 and 3.75 µm ± 0.78 for the AFSD materials fabricated at 1 and 4 mm/min deposition feeding rates, respectively, at 400 rpm/min. Among the feeding rates used, the 3 mm/min and 400 rpm rod rotation speed produced an AA7075 deposited part possessing the highest average hardness of 165 HV ± 5 and a compressive strength of 1320 MPa.

The Impact of Temperature Conditions on the Manufacturing Process and Mechanical Behavior of Beverage Can Ends during Operation.

This article investigates the impact of temperature regimes, corresponding to various climatic zones, on the manufacturing process and operation of beverage can ends made of aluminum alloy AA5182. The production process of aluminum beverage can ends involves multiple steps, including melting, rolling, and stamping, where different temperatures can influence both the production process and the properties of the final product. Furthermore, the mechanical behavior of the final product is affected by the aging process of alloy AA5182, which progresses at varying rates depending on the temperature conditions during storage. The objective of this study is to simulate the production process under various climatic conditions using the finite element method (FEM) and experimentally investigate the dependence of the strength of alloy AA5182 can ends on storage time and temperature. The findings of the study reveal that, under temperature conditions corresponding to warmer climates, the punching force can be reduced by approximately 15% compared to production in colder climates. Additionally, the strength of the finished can exhibits a decrease of about 10% during a month of storage in a warm climate, while no significant decrease was observed in colder climates. These results hold practical significance for the beverage production industry, as the manufacturing and operation of beverage cans are localized in diverse climatic zones.

Mechanical Properties of Welded by Friction Stir Welding Aluminium Alloy AA 5754

Friction stir welding is one of the most original methods for welding devised in recent years. As this welding method possesses advantages compared to conventional fusing welding methods, scientific research on its features and improvement is increasing. The advances in the knowledge of the process of friction stir welding allow its increasing application in different areas, such as aircraft and automotive industries, railway transport, nuclear industries etc. During friction stir welding the joined parts are in a solid state. This welding method is mainly used for joining aluminium and its alloys.The stirring and mixing of the material and the temperature during friction stir welding are the main factors that determine the possibility of obtaining weldments with precise mechanical properties.The present study aims to research the influence of the pin`s configuration on different quality aspects of the weldments at chosen parameters of the welding mode. To achieve this, pins with different geometry and coatings were used. Results that demonstrate the influence of the pin`s geometry and the process parameters on the temperature, structure, and mechanical properties of joined by friction stir welding weldments of aluminium alloy AA 5754 4 mm thick are presented. The influence of the pin`s geometry on defect formation during welding was determined.

Multiscale modeling of particle-induced damage in AA7075 aluminum sheet at large plastic strains

Large plastic deformation and ductile damage in precipitation hardening aluminum alloy AA7075 is driven by plastic flow in the vicinity of particles as well as fracture and decohesion of second phase particles embedded in the matrix. The current work investigates the deformation and damage characteristics of Fe-rich intermetallic particles, and η and θ precipitates in AA7075-O sheet. A multiscale model simulation methodology is presented and applied to analyze large-scale plastic deformation and damage characteristics. The methodology utilizes nanoscale molecular dynamics simulation to obtain matrix-particle interface strength properties and Weibull statistics to capture experimental fracture characteristics of particles. The above sub-models are incorporated within a 2-D real particle microstructure-based finite element model to conduct a comparative study of the roles of decohesion and fracture in the development of plasticity and void damage in AA7075-O sheet. In addition, in-situ SEM uniaxial tensile tests are carried out to assess the effectiveness of the simulation methodology and to compare the experimental and numerical results. Post-test high resolution X-ray computed tomography (HR-XCT) was also carried out to qualitatively observe particle-induced voiding in the material. The numerical methodology is shown to capture well the experimental trends in damage evolution of the individual particles. It is observed that particle damage is a function of inherent particle properties, their morphological features, and matrix strain localization characteristics. Larger-size Fe-rich particles are observed to undergo damage at an earlier stage, and consequently, affect the strain localization characteristics the most. In contrast, η precipitates are found to be most resistant to particle damage, followed by θ precipitates. Higher stresses inside strain localization bands, caused increased void damage initiation and growth of η and θ precipitates. Overall, particle fracture is observed to be marginally higher compared to particle decohesion, irrespective of the particle type.

Analysing the Influence of Tool Pin on Mechanical Properties of Friction Stir Welded Dissimilar Aluminium Alloys AA6082 & AA5052

Analysing the Influence of Tool Pin on Mechanical Properties of Friction Stir Welded Dissimilar Aluminium Alloys AA6082 & AA5052

Experimental study on high temperature tensile behaviour of aluminium alloy AA5083 with oscillating load

The flow behaviour of aluminium alloy AA5083 at 450 ^circ C has been investigated under quasi-static loading conditions with and without a superimposed oscillating load. Samples were placed under tensile load at constant strain rates ranging from 0.001 to 0.3 s^{-1}. A fixture was designed to generate the required sine-wave oscillation and was attached to the MTS tensile test machine along with a secondary, highly sensitive load cell. The frequencies of the imposed oscillations ranged from 5 to 100 Hz with an amplitude ranging from 0.02 to 0.5-N. It was observed that the imposition of oscillations influences the deformation behaviour of the material. Although the yield and tensile strength remain relatively constant, the total elongation is 8–23% higher under an imposed oscillating load. In addition, the thickness distribution profiles along the gauge length of the tensile specimens were investigated and it was observed that in the presence of oscillations the thickness distribution is more uniform. It was concluded that the presence of a superimposed oscillative load will result in greater deformation capabilities before fracture and postpone the occurrence of damage compared to conventional forming. This phenomenon was further explored utilising a user-defined material subroutine developed for the finite element solver LS-DYNA to simulate the conducted constant load tensile tests.

Investigation of the mechanisms on the abnormal features observed in thermal-mechanical testing of AA6061 under extrusion conditions

Hot extrusion is the most common forming technology for aluminium alloy AA6061 due to its good extrudability, and thus it is important to study its high-temperature deformation characteristics. In this study, three abnormal features are observed in thermal-mechanical testing under extrusion conditions of AA6061 specimens from one billet: 1) Two types of specimens with grey-coloured surface or silver-coloured surface appear after solution heat treatment (SHT); 2) The silver-coloured specimens show orange peel surface after hot compression tests; 3) The silver-coloured specimens have lower flow stresses than the grey-coloured specimens. This paper investigates the mechanisms behind the above abnormal features. A laser scanning confocal microscope is employed to examine the surface roughening, and electron back scatter diffraction is used to characterise microstructural changes. It is found that the main causes of the above behaviour are due to different initial grain morphologies and the evolution of dislocation density after SHT. The silver-coloured specimens initially have smaller columnar grains which undergo recrystallisation and extensive growth during SHT, and the dislocation density decreases significantly, leading to orange peel defect and low flow stress during compression tests, respectively. The grey-coloured specimens have larger columnar grains. After SHT, some grains undergo recrystallisation, but others still maintain the shape of the large columnar grains, and the dislocation density does not change significantly, resulting in surface oxidation with smooth surface after thermal-mechanical testing and 10–25 MPa (30–50%) higher flow stress compared to the silver-coloured specimens in compression tests.