Alloy Sheets Research Articles

Fabrication of three-layered aluminium-copper laminated composites using friction stir additive manufacturing

Abstract The current study employed the friction stir additive manufacturing (FSAM) method to fabricate three-layered laminated composite by utilizing 3 mm thick sheets of AA6061-T6 alloy (top and bottom layers) and pure Cu (middle layer). The feasibility of FSAM in producing high-performance Al/Cu/Al laminated composites was evaluated by analyzing the influence of tool rotational speed on the microstructure and mechanical properties. The composites were fabricated at rotational speeds of 900 rpm, 1200 rpm, and 1500 rpm; maintaining a traverse speed of 90 mm min−1 throughout the experiments. Changes in the weld morphology, macrostructure, microstructure, and intermetallic formation were noted and analyzed. The findings indicated that achieving macro defect-free joints is possible with a rotational speed of 1200 rpm. Detailed examinations via electron dispersive spectrum and x-ray diffraction revealed the presence of AlCu, Al2Cu and Al2Cu3 intermetallic compounds within the nugget zone. Significantly varied microhardness levels ranging from 59.4 to 143.7 HV0.1 were observed, corresponding to distinct microstructural features within the processed zone. The Al/Cu laminated composite exhibited an excellent combination of strength and ductility; a UTS of 214.6 MPa and an elongation of 23.4%. The findings showcase that utilizing FSAM presents an exceptional opportunity to fabricate novel Al/Cu multilayered composites with distinctive mechanical properties.

Formability Assessment Based on Q-Value for Optimizing the Deep Drawing Process of Automotive Parts Made from Aluminum Alloys Sheet

This paper presents a novel Q-value-based formability assessment for optimizing deep drawing processes. The Q-value, derived from thinning limit diagrams (TLDs), uses offset thinning and wrinkling limit curves to define severity levels. It is calculated by summing the product of Pascal’s triangle weighting factors and normalized element counts within each severity level. The effectiveness of this Q-value assessment was demonstrated using experimentally validated finite element analysis (FEA) to optimize blank size, tool geometry, and drawbead design (male bead height and contra-bead radius) for a deep-drawn AA5754-O automotive fuel tank. Validation of FEA results with experimental thickness measurements showed that the Barlat and Lian 1989 yield criterion provided higher accuracy than Hill’s 1948 model. An optimal condition, determined using the Q-value, consists of a 430 mm × 525 mm blank formed by a redesigned tool cooperated with optimized semi-circular drawbead geometries, achieving experimental significant formability improvements by minimizing wrinkling and thinning. During optimization, this study revealed a significant interaction between blank width and length, which influenced formability. Side-wall wrinkles were attributed to insufficient tool support for the blank during forming and were relieved through tool redesign. Furthermore, increasing the male drawbead height effectively reduced wrinkling but led to increased thinning, whereas increasing the contra-bead radius had the opposite effect.

Influence of Heat Treatment on Properties and Microstructure of EN AW-6082 Aluminium Alloy Drawpieces After Single-Point Incremental Sheet Forming

An EN AW-6082 aluminium alloy is one of the 6000 series aluminium alloys with the highest strength properties. Due to its favourable strength-to-density ratio, it is used, among others, in the automotive and aviation applications. It is also characterised by good formability, especially in the annealed condition. This article presents the results of investigations on the possibility of forming a 2 mm thick EN AW-6082 alloy sheet using the incremental sheet-forming process depending on the material condition (O, W, T4, T6). The microstructure of the material after heat treatment and the mechanical properties of the workpiece material in as-received state, as well as after forming, were examined. Additionally, for selected cases, additional heat treatment of the drawpieces was performed to improve their mechanical strength. The values of the limit-forming angle were determined for the materials tested. The values of this angle varied from 69° for the annealed sheet to 61° for the material in the T6 condition. The highest yield stress (YS) and ultimate tensile strength (UTS) were found for sheets (YS = 305 MPs and UTS = 324 MPa) and the artificially aged drawpieces (YS = 333 MPa and UTS = 390 MPa). Additional ageing after incremental sheet forming resulted in an increase in strength properties compared to drawpieces without additional heat treatment only in the case of drawpieces made of sheet metal after the solutionising and in T4 condition.

Optimizing microstructure for enhanced performance: A novel approach to EMI shielding with thin Mg98.5Zn0.5Y alloy sheets

Optimizing microstructure for enhanced performance: A novel approach to EMI shielding with thin Mg98.5Zn0.5Y alloy sheets

Experimental Validation of non-associated flow rule and hydraulic bulge forming simulation for a 6000 series aluminum alloy sheet

Experimental Validation of non-associated flow rule and hydraulic bulge forming simulation for a 6000 series aluminum alloy sheet

The deformation behavior of Mg-2Zn-0.1Ca alloy sheet: The role of strain rate

The deformation behavior of Mg-2Zn-0.1Ca alloy sheet: The role of strain rate

Computational study of pre-deformation influence on grain-scale deformation of AZ31 magnesium alloy sheet with bimodal non-basal texture undergoing uniaxial tension deformation at room temperature

Computational study of pre-deformation influence on grain-scale deformation of AZ31 magnesium alloy sheet with bimodal non-basal texture undergoing uniaxial tension deformation at room temperature

The effect of forming passes on the springback and microstructure of magnesium alloy sheets in roll bending

The effect of forming passes on the springback and microstructure of magnesium alloy sheets in roll bending

Numerical Study of Tungsten Cathode Characteristics During TIG Welding

Tungsten Inert Gas (TIG) is widely utilized across various industries. The understanding of tungsten electrode behavior, key component in this process, is vital for optimizing processes and enhancing weld quality. The shape of the electrode tip, influenced by its operational characteristics, significantly impacts the behavior of the electric arc and, consequently, the quality of the welded assembly. This study aims to analyze the influence of current intensity on the thermal and electrical characteristics of the cathode tip during TIG welding, using numerical simulations conducted with Comsol software. The analyses are carried out by applying Direct Current (DC) welding on an aluminum alloy sheet. The results show a similar evolution in the operational characteristics of the electrode as its tip angle varies. In contrast, the current intensity affects only the temperature, which increases with a higher tip angle, while the current density depends solely on the geometry of the electrode tip. The appropriate selection of welding parameters is imperative to preserve the electrode shape and ensure an efficient welding process.

On the drawability prediction of AA5754 aluminum alloy sheet

In order to study the drawability of AA5754 aluminum alloy blank, the numerical predictions of fracture failure behavior caused by cup drawing of metal sheet were carried out by using the GTN model and the thermodynamic-based continuous damage mechanics (CDM) model. The CDM model coupling the nonlinear isotropic and kinematic hardening laws with the isotropic ductile damage model was developed to carry out the numerical computation in the form of the user material subroutines. Although the forming limit curves predicted by GTN model and CDM model are distinctly different, but both of them are feasible to characterize the formability of metal sheets. The numerically predicted drawability of metal sheet is in good agreement with the experimental results in terms of strokes, sheet thinning and fracture failure location. The effects of sheet original thickness and friction coefficient between punch and sheet on the drawability of metal sheet were further investigated in detail.

Assessment of surface treatment methods for strengthening the interfacial adhesion in CARALL fiber metal laminates

Metal and polymer interface bonding significantly influences the mechanical performance of fiber metal laminates (FMLs). Therefore, the effect of surface treatments (mechanical abrasion, nitric acid etching, P2 etching, sulfuric acid anodizing (SAA), and electric discharge machine (EDM) texturing) carried on aluminum 2024-T3 alloy sheets was evaluated considering surface morphology, surface topography, and surface roughness. Further, the influence of surface treatments on interfacial adhesion strength and failure mode between the aluminum alloy and carbon fiber prepreg was investigated. The surface treatments increased the surface roughness of the aluminum substrates. Surfaces treated using SAA, nitric acid, and P2 etchant showed improved wettability, while mechanically abraded and EDM textured substrates showcased hydrophobic behavior. The selected surface treatments significantly affected interfacial adhesion between the epoxy polymer and aluminum alloy. SAA and EDM texturing greatly enhanced the interfacial peel strength of FMLs. In the case of interfacial shear strength, EDM textured substrate showed superior performance, followed by SAA. Moreover, untreated and mechanically abraded specimens exhibited weaker bonding and adhesive failure at the aluminum-epoxy interface, whilst chemical treatments resulted in mixed model failure. EDM textured surface underwent cohesive failure, while a dominant mixed mode failure and fiber adhesion were observed in the SAA-treated specimen.

Revolutionizing automotive lightweighting: a comparative analysis of electromagnetic free forming for clamped sheets

Reducing vehicle mass is a critical strategy for enhancing fuel economy and meeting the growing demand for lightweight materials in the automotive industry. Aluminum alloys have emerged as a promising solution due to their low density, but their limited formability compared to steel poses significant challenges. Electromagnetic Forming (EMF) is a high-speed process capable of significantly improving the formability of aluminum alloy sheets, enabling the production of lightweight structural components for automotive applications. This process operates within microseconds, which provides a unique advantage for rapid and efficient manufacturing. The numerical modeling of EMF plays a pivotal role in understanding the complex physics and deformation behaviors associated with this process. This research investigates the numerical modeling of EMF for various aluminum alloy sheets using a spiral coil. The results provide insights into the distinctive deformation behaviors and performance variations of different alloys under identical process conditions, which offers valuable guidance for material selection and process optimization in automotive applications.

Incremental sheet forming of dissimilar friction stir welded AA1100 and AA6061 blanks using single point tool

Recently, single point incremental forming (SPIF) gained popularity among researchers as well as in industry as a die - less flexible forming technique. In this work, two different metal sheets of Aluminium alloy, AA1100 and AA6061, each of thickness 1.2 mm is welded together to produce a tailor welded blank utilizing Friction Stir Welding (FSW) which is done by vertical milling machine and the forming operation is performed on the tailor welded blanks as well as base sheets. The main objective of this study is to identify the input factors affecting FSW process, compare the formability of the tailor welded sheets and to find out optimum step depth, feed and speed of SPIF. The single point incremental sheet forming is done using CNC Milling machine and optimized the experiment results using Taguchi method. After conducting the experiments, the spring back, surface roughness, wall angle, and formability is measured and Signal to Noise ratio, means were calculated. With the help of graphs, optimum parameter values were obtained using Minitab software. From analysing the results revealed that the step depth and spindle speed are the critical parameters affecting the incremental sheet forming process.

Application of Powder-Bed Fusion of Metals Using a Laser for Manufacturing of M300 Maraging Steel Tools Intended for Sheet Metal Bending.

This paper presents the results of a pilot application of Powder-Bed Fusion of Metals Using a Laser (PBF-LB/M) for the fabrication of M300 (1.2709) maraging steel sheet metal bending tools. S235 steel was used as a substrate for the fabrication of bending punches. The main goal of the research was to determine the usability of such tools without heat treatment, which would contribute to the increase in the cost of tool production. Industrial tests of tools were conducted during the forming of Inconel 625 and AW-6061 T0 aluminium alloy sheets. The punches were subjected to tests of surface roughness, hardness, microstructure, porosity, and geometric quality in order to verify the quality and accuracy of tools made by the PBF-LB/M technique before and after experimental investigations in industrial conditions in a selected manufacturing company. It was found that tools with an M300 steel working layer after the PBF-LB/M process without heat treatment show suitability for bending sheet metal in a certain range of force parameters, ensuring obtaining elements after bending from Inconel 625 and AW-6061 T0 aluminium alloy sheets of the required geometric quality.

Enhancing Welding Productivity and Mitigation of Distortion in Dissimilar Welding of Ferritic-Martensitic Steel and Austenitic Stainless Steel Using Robotic A-TIG Welding Process

The P91 martensitic steel and 304L austenitic stainless steels are two mainly used structural steels in power plants. The major problem in conventional multipass tungsten inert gas (TIG) welding of P91/304L steel is high heat input and joint distortion, increased cost and time associated with V groove preparation, filler rod requirement, preheating and welding in multiple passes, and labor efforts. Hence, in this study, a novel approach of robotically operated activated flux TIG (A-TIG) welding process and thin AlCoCrFeNi2.1 eutectic high entropy alloy (EHEA) sheet as the interlayer was used to weld 6.14 mm thick P91 and 304L steel plates with 02 passes in butt joint configuration. The joints were qualified using visual examination, macro-etching, X-ray radiography testing and angular distortion measurement. The angular distortion of the joints was measured using a coordinate measuring machine (CMM) integrated with Samiso 7.5 software. The quality of the A-TIG welded joints was compared to the joints made employing multipass-TIG welding process and Inconel 82 filler rod in 07 passes. The A-TIG welded joints showed significant reduction in angular distortion and higher productivity. It showed a 55% reduction in angular distortion and 80% reduction in welding cost and time compared to the multipass-TIG welded joints.

Effect of Al7Cu2Fe Particles on the Anisotropic Mechanical Properties and Formability of Al-Zn-Mg-Cu-Based Alloy Sheets.

The presence of Al7Cu2Fe particles, formed due to Fe impurities in Al-Zn-Mg-Cu alloys, significantly impacts mechanical properties and formability, which is crucial for the use of these alloys in the automotive and aerospace industries. In this study, we prepared Al-Zn-Mg-Cu-based alloy sheets with large (LF), small (SF), and no (NF) Al7Cu2Fe particles to explore their effects on recrystallization and mechanical behavior. These sheets were fabricated using controlled cooling rates and subsequent thermo-mechanical processing. Fine dispersion of Al7Cu2Fe particles in the SF sheet led to a substantial reduction in grain size (16.5 μm) and an increase in yield strength (168.6 MPa), albeit with lower ductility (24.6%). In contrast, the NF sheet exhibited a lower yield strength (141.5 MPa) but superior ductility (35.8%) due to the absence of Al7Cu2Fe particles, which prevented premature fracture. The SF sheet demonstrated lower anisotropy in ductility due to the uniform recrystallized grain orientations, while the LF and NF sheets exhibited significant anisotropy in yield strength. These findings indicate that optimizing Al7Cu2Fe particle dispersion is key to balancing the strength, ductility, and anisotropy in Al-Zn-Mg-Cu alloys.

Relationship Between Fracture Fractal and Mechanical Properties of 5083 Aluminum Alloy Sheet Prepared by Alternate Ring-Groove Pressing and Torsion

In this study, the tensile fracture morphology of a 5083 aluminum alloy sheet prepared by alternate ring-groove pressing torsion and torsional flattening at room temperature (ARPT-TF-R) under different numbers of torsional flattening passes was analyzed. The box dimension method was used to calculate the fractal dimension, and formulas for the quantitative relationships between the tensile properties and Vickers hardness of 5083 aluminum alloy sheet under different process conditions and the fractal dimension were established. The results indicated that the fracture mode of the sheet prepared by one pass was microporous aggregation fracture, and the number of large-sized dimples was small. The plate prepared by two passes had a greater number of micropores, and the dimple size was relatively small. The fractal dimension of the aluminum alloy sheet prepared by ARPT-TF-R at room temperature was 1.77–1.84. As the number of torsional flattening passes increased, the yield strength, tensile strength, Vickers hardness, and fractal dimension of the aluminum alloy sheet increased.

Achieving enhanced strength-ductility synergy in heterogeneous equiaxed structured Ti-6Al-4V alloy sheets by cryogenic pre-stretching

Achieving enhanced strength-ductility synergy in heterogeneous equiaxed structured Ti-6Al-4V alloy sheets by cryogenic pre-stretching

Achieving springback-free age forming via dislocation-enhanced stress relaxation in Al alloy

Obtaining zero springback and good post-form performance simultaneously is an ultimate pursuit in metal sheet forming. The stress-relaxation ageing (SRA) behavior and mechanical properties of a commercial 2219 aluminum alloy largely pre-deformed (LPD) by 80% have been systematically investigated. The stress relaxation ratio of the LPD alloy reaches approximately 94% regardless of the initial stress (50-350 MPa) after ageing for 12 h at 140°C. This relaxation ratio is about 2.9 and 1.8 times that in the T4 tempered alloy (27.6% under 50 MPa and 31.5% under 150 MPa) and T3 tempered alloy (37.6% under 50 MPa and 51.2% under 150 MPa), respectively. The microstructures, comprised of GP zones/θ' precipitates plus dislocation tangles, and tensile properties in the stress-relaxation-aged LPD alloys remain basically invariant with different initial stresses, as is vital importance for property consistency at different locations of the formed part. Under the same SRA condition, the LPD alloy has an increase of 150-230 MPa in yield strength relative to T3/T4 tempered alloy and obtains a uniform elongation of about 8%. A simple dislocation-based constitutive model accurately describing stress relaxation enhanced by the high dislocation density is established and embedded in the finite element package through a user subroutine. Simulations and experimental verifications show the LPD alloy sheet parts exhibit a nearly zero springback (< 5%) after unloading in contrast to the springback larger than 65% in the T3/T4 alloy sheet parts under the same condition. Our findings demonstrate the high-dislocation-density-enhanced SRA response enables a high-performance springback-free age forming of Al alloy sheet.

Tensile strength and failure behaviour of clinched joint in cross-tension specimens of similar aluminium alloy sheets

This research investigates experimentally the tensile strength and failure behaviour of clinched joints in cross-tensile specimens made of similar aluminium Al5457-H22 alloy sheets. The cross-tensile specimens were joined by clinching using different tool geometry parameters, and the tensile strength behaviours of the joined sheets were investigated under various tool geometry parameters. Meanwhile, the influence of the tool geometry parameters on the tensile strength was recorded experimentally. Additionally, the failure mechanism was studied under static loading conditions. As a result, macroscopic observation showed that clinched joints’ pull-out failure mode with a circumferential direction crack was observed on a punch fillet radius of 0.3 mm and a punch angle of 2o, which mainly failed due to kinked cracks through the upper sheet thickness. Thus, the cross-tensile specimen test can be an excellent method to analyse the failure behaviour of the clinched joint of aluminium sheets subjected to pure tension.